Arduino Help

[wary cloak]

And since the pins I remember I used 22,23 and so, instead of u8 they would be intergers

And what things let us do that -?

[coral geyser]

Pin<..., ...> structs that variable pins holds in main.rs

[wary cloak]

You mean input output ig

Because we could in main declares the pins to be input/output and then send them to the new function or something or we could create another struct/enum inside keypad

And get rid of the columns and rows fields

[coral geyser]

How about 2 arrays?

rows: [Pin<..., ...>; 4], cols: ...

[wary cloak]

What's that inside the array?

[coral geyser]

The Pin structs

[wary cloak]

I'm a little bit confused

[coral geyser]

That let you set and read the pin's state

[wary cloak]

So we are indeed making pin structs?

Let's go step by step then.

[coral geyser]

They already exist

[wary cloak]

What

Oh yes

Pins macro creates a struct?

[coral geyser]

https://rahix.github.io/avr-hal/arduino_hal/port/struct.Pins.html yep

[wary cloak]

Ok so..

The pins struct contains all the pins of my board

So you suggest

That rows and columns

Are arrays that contains the specific fields needed from the pins struct

Right?

[coral geyser]

Basically

You can take the pins out of the struct that holds them

Like we did for the i2c

[wary cloak]

And ig brackets for generics or something because I could connect them almost any where

[coral geyser]

And the serial

[wary cloak]

We did that (?

When(?

[coral geyser]

pins.xx.into_output()

[wary cloak]

do you agree with the idea to have the same key struct from the C code inside the Keypad struct?

[coral geyser]

Do we need it? Isn't that what matrix will do?

[wary cloak]

The key struct has a field for the bit combination and another for the ASCII character to represent each key, tho in my C example for readability I made the matrix with all my key const struct instances

To represent each key

Tho ig you could also have the ASCII in matrix and a bit field for any key needed set of bits in the display struct

[coral geyser]

So I guess the main question is, are we doing the individual pin or PORTA method?

[wary cloak]

Ig we will do our own struct or whatever to replace it unless it isn't that much of a huge pain

Tho I was really considering to use unsafe..

Because I know is safe we won't mess up and it saves up so much code

[coral geyser]

Because individual pins don't need bit combinations

[wary cloak]

But how do you track which key is it

[coral geyser]

In the loop

[wary cloak]

Idk how the condition would be because that would make like 64 conditions

[coral geyser]

for r, row in rows.enumerate() {
  for c, col in cols.enumerate() {
    
  }
}

[wary cloak]

If pin 1 is this and pin 2 is this and pin 3 is this.. And pin 8 is this

Else

If pin 1 is this..

[coral geyser]

Loops

[wary cloak]

Mm

I just don't get it ig we will see

Let's try do individual pins

If it's so much of a pain we will use unsafe

[coral geyser]

So we need somewhere to put the pins

[wary cloak]

Wait first

So no key struct and no bit field?

[coral geyser]

Yep

[wary cloak]

Just columns and rows which the pins Corresponding to them and the matrix

With"

[coral geyser]

matrix will handle it

[wary cloak]

Well ok ao

[wary cloak]

I don't understand this

[coral geyser]

You have 8 wires going to the keypad right?

[wary cloak]

Doesn't the pins are already contain in a struct and we are extracting the ones we are using for an array?

[wary cloak]

Yes

[coral geyser]

The pins struct in main holds the "handles" to those 8 wires so you can read write to them

[wary cloak]

handles?

[coral geyser]

We need to get them from pins and put them in Keypad for later use

[coral geyser]

A handle is like a pointer

It represents something else

[wary cloak]

Is there anything that isn't a pointer (?

[wary cloak]

Mmmm

The thing is also to the eventual new function we should send

Hey I will use this pins for this

And inside it should take them

[coral geyser]

And put them somewhere

[wary cloak]

In the arrays

[coral geyser]

Exactly

[wary cloak]

So you told me

That we get say ownership of the handle or whatever

By calling methods into them like into output

[coral geyser]

Or you could have 8 individual variables

[wary cloak]

Just how many lines you want to write-?

I thought we should avoid that kind of stuff, agroup related data, avoid writing extra lines

[coral geyser]

For the mega the Pins struct from arduino_hal has 50+ pins in it each as an individual field

[coral geyser]

Yes, arrays will make it easier

[wary cloak]

So what do we do-

Man it hurts so much the absence of a library this should've been the second easiest part

[coral geyser]

^

[wary cloak]

in the lcd there was a clear direction of what to do but here it's just from scratch

[wary cloak]

Yeah I don't get how that works is it for taking generic or something the angle brackets

[coral geyser]

Do you have the docs open?

Because you should have them open to look stuff like this up

cargo doc --open

[wary cloak]

Exactly what I mean idk if that's something you made yourself or your know it's the way idk

[wary cloak]

Actually I don't even have the PC open because I knew I wouldn't be writing code soon -

[coral geyser]

<T> indicates a generic type

[wary cloak]

So I may turn it now

[coral geyser]

https://doc.rust-lang.org/book/ch10-00-generics.html

[wary cloak]

Gosh finally

I know generics it's just I don't understand like, anyway we will see+

-*

Avr or Arduino?

[coral geyser]

Arduino_hal

[wary cloak]

Pins?

[coral geyser]

I have been meaning to ask what do the different characters before ? mean in your messages?

[coral geyser]

Yep

[wary cloak]

Which ones you mean

"-" And "(? "

[coral geyser]

Yeah

[wary cloak]

Mmm hard to explain

• is like maybe

Surprise like

When someone says something and stops at the last letter

What sound dry and serious or something

What- sound like you know how I imagine a confused what to sound

[coral geyser]

Okay, makes sense

[wary cloak]

It would be easier if I could make the sounds

Tho as the other probably it stuck because of me talking a lot to someone who did something similar or something made it stuck

Now about (?

[coral geyser]

I think that would be a "What!?" For how I normal type

[wary cloak]

It's not necessary a question sometimes I just don't want messages to be dry or I don't want them to be taken as seriously or idk, this one is really complicated and either I'm just use to it or it's use would have to be explained by a psychologist at this point (?

[wary cloak]

Mines like a silent one like another kind of shock, as I said with sound it would be so much easier to explain this one

[coral geyser]

Maybe it's like a /s tag

[wary cloak]

Maybe is a shield for insecure statements who knows

Like I mean it but I don't

70 fields-

[coral geyser]

we need more!!!

[coral geyser]

https://toneindicators.carrd.co/#masterlist you will see people in this server use tone indicators a lot

[coral geyser]

See how each field is a Pin<..., ...>?

[wary cloak]

Btw this project that it's peak has, matricial keyboard 4x4, LCD display with I2C, 2 relay modules, an RFID, 4 ultra sound(? ) sensors and one Infrared (?) Sensor

Could be done in the raspberry pi pico or there's a pin shortage?

[coral geyser]

100+ pins is the minimum I will accept /j

[wary cloak]

There are like a lot of nested angle brackets, why?

I need a raspberry Pi pico Mega..

[coral geyser]

They are generics in generics

Pin<[mode], [number]>

[wary cloak]

The first is for input/output the one inside for? And the one in the same brackets

What number?

[coral geyser]

The port number

PE0 is port E pin 0

[wary cloak]

So my pin has inside information of it's state as input output, it's port and number, right?

[coral geyser]

The one instead of Input is what type of input it is

[wary cloak]

That's a no btw?

[coral geyser]

Yep

[coral geyser]

I don't remember how many pins the pico has easily accessible

[wary cloak]

Wdy by type of input? That of pull up or pull down?

[coral geyser]

But I suspect not enough

[wary cloak]

Yeah me too :(

It's so sad

I have no clue what I'm going to use the raspberry Pi pico on

It's likely gonna get dusty

I need bigger boards pls raspberry don't do this to me-

[coral geyser]

Search "mode" in that docs window

[wary cloak]

I will ask you still to set up all so I could be able to work with it but I don't see use in it

[coral geyser]

Go to arduino_hal::port::mode

[wary cloak]

Why embedded need to be so expensive-

[wary cloak]

So I go back? Because there's no mode here

[wary cloak]

I only buy the micro because if needed and possible I want to work with it and I have to take my chance while it's still relatively cheap

[coral geyser]

You haven't even seen FPGAs

[wary cloak]

But I'm frustrated that I'm doing nothing on it

[coral geyser]

Those things can be 1000+ dollars

[wary cloak]

.

[coral geyser]

Hmm, that's what the path should be

https://rahix.github.io/avr-hal/arduino_hal/port/mode/index.html is the online one

[wary cloak]

As I showed you

[coral geyser]

Click "port" in the path at the top

[wary cloak]

Got there

Oh right

It could analog or digital

But..

The others..

Do I need to know what this modes are?

Pin<input/output<type of input/output>, port and pin number>

Right?

[coral geyser]

Yep

There is also a special thing you can have in the port and pin number position called Dynamic

Which let's it be any port and pin (the port and pin are stored inside the Pin struct)

[wary cloak]

Well that seems kinds convenient for us..

[coral geyser]

I know right

[wary cloak]

We know the type.. We just need a dynamic pin and port..

Blinky blinky

[coral geyser]

So what type should cols be?

And what type should rows be?

[wary cloak]

Column digital input and rows digital output

[coral geyser]

What type for each?

[wary cloak]

What do you mean there?

[coral geyser]

Or well mode I guess

[wary cloak]

Oh

As I said columns input and rows output

[coral geyser]

Input<?>

[wary cloak]

Digital?

Why isn't digital a thing

It's literally the default

You use 98% of the time

[coral geyser]

Because it's Floating or PullUp

[wary cloak]

What's the difference between the two?

[coral geyser]

Floating pins are basically completely disconnected from anything

PullUp ones will go to 5v by default

[wary cloak]

Well there's output at least for rows, that says is configured as digital output

Where would I use each one? Which one do I normally use?

So either empty or they work as Vcc? Or what?

[coral geyser]

Floating is the default one

[wary cloak]

And why would I use pull up instead of floating?

[coral geyser]

Well what happens if you attempt to read a floating pin not connected to anything? We don't know it can report as 1 or 0

[wary cloak]

Why would I read a pin that has nothing to read

[coral geyser]

You can actually change the state by just moving your hand around it sometimes

[coral geyser]

Are the pins going to the keypad connected to anything when the key isn't pressed?

[wary cloak]

Eh..

The columns

[coral geyser]

And by connected I mean to 0v or 5v

[wary cloak]

Which are inputs

[coral geyser]

But if it's not pressed...

[wary cloak]

Mmmm I don't remember ...

[coral geyser]

Then it isn't connected to the columns

[wary cloak]

Let's see if I can remember with this

This is when someone remembered me how a matricial keyboard worked

Well not "someone" My teacher

Tho this is in

Negative logic

But replace in your mind 0 and 1(?

By default rows are 0

Until you press it then it's 1

Columns start at 0 but we chose when and how many are 1

But ofc the way we use it

It's only have 1 at a time to have a 1 and then keep passing it to the right

Tho idk

How to answer your question

Because

There are wires connected to the pins

And also

In Arduino I just passed the pins without worrying about if they had or not to be pull up to know

[coral geyser]

Some ARM code I finally found from an old project

[wary cloak]

That seems long and complex (?

So you know what kind of pins they are and why(?

[coral geyser]

yeah, I can explain it if you want

[wary cloak]

If it ain't complicated

[coral geyser]

So these keypads assuming its one of these

[wary cloak]

What's GPIO btw

Yeah it's one of those

The third one

[coral geyser]

General-Purpose Input/Output

[coral geyser]

These are a matrix of switches

each switch connects the row wire with a column wire

[wary cloak]

This(?

[coral geyser]

yep

[coral geyser]

Do you have the connection to 5v as shown there?

the resistors to vcc

[wary cloak]

I don't use resistors I just connect the wires

[coral geyser]

or are they just connected to other pins

[wary cloak]

That

[coral geyser]

So in that case the inputs if they are set to floating don't have 0v or 5v to set that state

if no buttons are pressed

[wary cloak]

I realized I mixed input with output all this time here

I don't understand why resistors change that

[coral geyser]

The resistors in the diagram above "pull" the wires towards 5v

[wary cloak]

And why outputs don't need them?

[coral geyser]

The resistors are there to allow you to pull them to 0v to override them

[coral geyser]

Because they are outputs they control their own state

[wary cloak]

So this has to do with inputs needing to be either 0 or 5 volts and being controlled by whoever press them instead of internationally by code?

[coral geyser]

yes

If nothing external pulls an input to 0v or 5v we don't know what it will read

[wary cloak]

Oh because there noise that makes it unstable

[coral geyser]

yep

[wary cloak]

So the resistors avoid noise so it could be 0 until it's told to be 5 voy

Volt*

Ok got it

So columns are going to be digital output floating dynamic pins and rows are going to be digital pull up input dynamic pins

4 of each

[coral geyser]

Not quite

We should fix the whole accidentally shorting pins issue

[wary cloak]

Accidentally shorting?

[coral geyser]

I will pull the example from my microelectronics textbook

[wary cloak]

Oooh

[wary cloak]

You mean short circuit by pressing down two at a time

Right?

[coral geyser]

yep

[wary cloak]

Tho idk why that short circuits

[coral geyser]

as seen here we can short pins by accident

[wary cloak]

Let get a more base explanation

What would you define a short circuit to be

And what can cause it and what are the consequences

[coral geyser]

Say one row (I think this diagram is backwards to how you have done it) is set to output 1 and one is set to output 0

[coral geyser]

Then we connect these to pins together by pressing the correct set of buttons

[wary cloak]

Nah it's the same columns are the lower wires(?

[coral geyser]

connecting 5v to 0v

[wary cloak]

Oh wait

If columns are input yes

[wary cloak]

[coral geyser]

one one side, maybe it just causes your micro controller to restart, on the other ... dead micro controller

[wary cloak]

So..

[coral geyser]

if you connect 5v to 0v directly without any resistance, and infinite amount of current will flow

[wary cloak]

Ok I get that

[coral geyser]

which is very bad for electronics

[wary cloak]

And micro components would heat and be useless?

[coral geyser]

yep, they can basically explode internally

[wary cloak]

In what case does this reset the micro instead of killing it?

[coral geyser]

though luckily the arduino pins are protected somewhat against this

[wary cloak]

I heard there were internal resistors in the pins

That you could use instead of your own with pull up

[coral geyser]

That's the thing protecting the chip

[wary cloak]

Ok so now that we more or less understand what a short circuit it's and what it does continue on why two inputs at a time short circuit this

[coral geyser]

So how we fix this issue of 0v connecting 5v is just not have 5v being directly connected to the keypad through output pins

[coral geyser]

You can connect 2 outputs together accidentally

[coral geyser]

^

[wary cloak]

I don't see how at all..

Because

So my outputs would normally

Have a 1 constantly moving

And the rest 0

And the then the inputs

Also be all 0

[coral geyser]

you can connect the 1 output to a 0 output

[wary cloak]

Until I press something

Ok I get that now

But how would that while thing work?

Like..

They have to be two buttons of the same column

Or whichever

If they are from the same column we have the column with 1 and two rows in the same column with 1

If it's from another the row would be 1 but column 0 at least me I can't see the connection that allows that to happen

[coral geyser]

I am confused by these two messages

[wary cloak]

I just can't see why pressing a second key

Connects one column to another

Because I only see the connection between a column and it's four rows

[coral geyser]

press 2 keys in the same row

that will connect 2 different columns together

[wary cloak]

This the kind of thing it's impossible to explain without a whiteboard-

[coral geyser]

https://witeboard.com/bc66e2b0-1536-11ed-aae1-b1393404fc0e

you should be able to draw on that

[wary cloak]

i am really bad so let s see..

ok so

do you see me or it is for me to take a screenshot?

[coral geyser]

are we doing rows or columns as input?

[coral geyser]

I can see it live

[wary cloak]

as I learn it columns as outputs i control and rows like inputs

so

say we pressed..

row 3 and the 1 is in column 2

ok so now

we also press r2

so..

it is like the same

two rows in 1 but to the same column

[coral geyser]

what happens if you now press R3,C3

[wary cloak]

it makes the same path of

ok lets see

do i erase r3 c2?

[coral geyser]

keep them

say the 3 in green are pressed

[wary cloak]

three at a time_?

well then..

[coral geyser]

what is R3's state?

[wary cloak]

i could see a connection there

by pressing two from different columns

but not from the same

[coral geyser]

^

[wary cloak]

so it is not garanteed short circuit but kinda likely and in any case there should not be even the slightless chance of shortcircuit, right

[coral geyser]

yeah, we don't want it to accidentally happen

[wary cloak]

Ok understood

So how do we avoid it?

[coral geyser]

So what if instead of using 0 on the output we just made the pin disconnected from the microcontroller

[wary cloak]

Well that makes sense logically because there wouldn't be any Posible 5v to 0v but rather 5v to nothing

Tho wouldn't resistors technically do it also?

[coral geyser]

cool, so we do that

[wary cloak]

But how do we make them disconnected?

[coral geyser]

it's fine if it's through a big reistor

like the ones inside the microcontroller

[wary cloak]

So why don't we use those?

[coral geyser]

That would be the open-drain mode

[wary cloak]

.

[coral geyser]

They aren't connected by default when you set it to output

[wary cloak]

I read the description btw and it says

OpenDrain Pin is configured as a digital output with open drain behaviour

What's open drain behavior and how it works is the thing

[coral geyser]

Open drain acts to connect to 0v when set to low, and disconnect the pin when set to high

[wary cloak]

And we can't set them?

[wary cloak]

What-

[coral geyser]

only some pins can

[wary cloak]

But I would disconnect it when I want to use it

Or I would have to

So negative logic?

Do*

[coral geyser]

but, what if we made the input default to being high

[wary cloak]

Noooo negative logiiiic

But I understand

That's why the examples seem to always be with negative logic I see

[coral geyser]

Its setup this way because transistors that pull to 0v are smaller than transistors that pull to 5v

[wary cloak]

But 0v would do? Don't we kinda need 5?

[coral geyser]

because chemistry

[coral geyser]

we let the inputs pull to 5v by default, aka PullUp inputs

[wary cloak]

I didn't understand that part honestly

First

Pull up wasn't to use the resistors inside?

[coral geyser]

A pullup input is configured to connect a high value resistor to the pin and 5v

[wary cloak]

Second are we specifying two types for one pin?

[wary cloak]

So it's low is 5 volt as a default state?

[coral geyser]

Input<PullUp> for inputs, Output<OpenDrain> for outputs

[wary cloak]

But..

[coral geyser]

yes, we will consider 5v (high) as a logic false

[wary cloak]

Let's start with inputs

So

I thought we used pull up on inputs

Because of the noise

[coral geyser]

that to

[wary cloak]

So it could be set to 0 and then to 5 when asked

Not that also

[coral geyser]

but it just happens to also fit perfectly for using OpenDrain

[wary cloak]

It made it constantly 5 volts

[coral geyser]

it defaults to 5v but doesn't force it to be 5v

[wary cloak]

So inputs pull up uses the pin resistor and a default 5 volt state to avoid noise and work with negative logic?

And then the outputs would be open drain so there's never a 5v to 0v connection

But

If the maximum outputs can be is 0 volt

What about passing a one as we did before? Like

[coral geyser]

yep

[wary cloak]

Before two 1's needed to match so

I guess when I press it down it would be 0 the row and the column would be either nothing or 0

So I guess two 0's would need to match

[coral geyser]

you will see a 0 on the input only when the column is set to 0 and the button connecting them is pressed

[wary cloak]

Ok so now that we talked all of this

How we implement it on the struct?

[coral geyser]

rows: [Pin<Input<PullUp>, Dynamic>; 4],
columns: [Pin<OpenDrain, Dynamic>; 4],

[coral geyser]

I had an extra >

[wary cloak]

..

Where?

I don't see it

[coral geyser]

after OpenDrain

should just be a ,

[wary cloak]

I thought it should be like input pull up above

[coral geyser]

for some reason it's not

No idea why

[wary cloak]

Ok now that we finally had been through all this logic and how it works and we made the struct that holds that matrix of possible ASCII characters with the fixed sizes of 4x4 and the pins for the columns and rows so it could be what ever pin from whatever port but with the fixed size of 4 pins that have the configuration to work as we need them too and avoid short circuits.. What now?

struct Keypad {
    rows: [Pin<Input<PullUp>, Dynamic>; 4],
    columns: [Pin<OpenDrain, Dynamic>; 4],
    matrix: [[char; 4]; 4]
}

[coral geyser]

shouldn't X and Y be 4

[wary cloak]

Oh yeah I could swear I changed that

[coral geyser]

next step: we need a new function to make these things

[wary cloak]

So

New would receive

I anotate the types the same way?

We could use an alias maybe for the pin types of rows and columns

Like

[coral geyser]

yep

type ColumnPin = Pin<OpenDrain, Dynamic>;

[wary cloak]

Type [Pin<Input<PullUp>, Dynamic; 4] = row_pins

I forgot how it was

But yeah that

[coral geyser]

go ahead

if it will help you manage it and read it then its good

[wary cloak]

Shouldn't we use snake case?

[coral geyser]

types are camel case

[wary cloak]

Oh ok

?

[coral geyser]

you need to name them rows: ...

[wary cloak]

Btw maybe I need a more descriptive name for matrix if any suggestions

[wary cloak]

In the struct use the alias you mean?

[coral geyser]

also either you need to make the type aliases arrays or put the arrays in the function signature

[coral geyser]

fn new(rows: RowPins, columns: ColumnPins, matrix: Matrix) -> Self {
  ...
}

[wary cloak]

Oh

[coral geyser]

and that also

I am going to switch to Windows real quick

[wary cloak]

By change have any better idea for the matrix type alias?

Because matrix is kind of an already existing thing so idk

struct Keypad {
    rows: Rowpins,
    columns: ColumnPins,
    matrix: matrix
}

type ColumnPins = [Pin<OpenDrain, Dynamic>; 4];

type Rowpins = [Pin<Input<PullUp>, Dynamic>; 4];

type matrix = [[char; 4]; 4];

impl Keypad {
    fn new(row: Rowpins, column: ColumnPins, matrix: matrix) -> Self {

    }
}

[coral geyser]

and back

[coral geyser]

seems fine

naming is hard

[wary cloak]

Ok so

I'm still not used to making new functions

I know how to do constructors but I don't remember new function being the same in syntax

How do I complete new?

[coral geyser]

Self {
  rows,
  columns,
  matrix,
}

[coral geyser]

Rowpins should be RowPins

[wary cloak]

Solved

[coral geyser]

and matrix should be Matrix

[wary cloak]

impl Keypad {
    fn new(row: RowPins, column: ColumnPins, matrix: Matrix) -> Self {
        Self {
            rows,
            columns,
            matrix,
        }
    }
}

Ok so know we have a keypad struct with a matrix of the possible ASCII characters and the pins with the already correct setup of rows and columns and a new function

Two questions

First

That means when I declare the pins I want to use I won't be calling into_output and stuff?

[coral geyser]

You will, then you will pass them to the new function

[wary cloak]

Also I made the struct and new function public this time I ain't forgetting

[wary cloak]

But didn't already tell how I wanted the pins to be in the types?

[coral geyser]

yes, but they start as Input<Floating>

[wary cloak]

Well what's next now?

I guess we should

Work with ok we have this data

[coral geyser]

what methods do you want this struct to have

?

[wary cloak]

How with this data can we make a function to detect the pressed key and return it?

Tho to be honest

The only thing I really need and use

It's waitForKey

But I think is very basic to have that functionality also ig

So a getKey method and waitForKey method should be enough

At least for the purposes and scope of this project

Tho

There one other use this will have

[coral geyser]

alright setup their signatures

[wary cloak]

I will tell you in case maaaaybe

[coral geyser]

and just put todo!() in the body of them

[wary cloak]

Another function would do

Did I told you about master mode and passwords?

[coral geyser]

you did

[wary cloak]

That is where the current project is stucked but

Because of the rfid

Because I successfully

Obtained the password from the user and compare it to another

Well if there's a function that would help like allowing use to write a string or give back a char array and we pass it as a parameters how many letter we want to write

That could help and sound useful

Or it could be not necessary enough for me it sounds really cool but what do you think?

[coral geyser]

put all the methods you want

[wary cloak]

Should we call it..

getCharArray?

Btw it's likely the two above would call getKey to do the dirty job and then add to it

[coral geyser]

make sure the types make sense

[wary cloak]

So the actually tricky thing is to do getKey

[wary cloak]

Wdym?

[coral geyser]

for the functions, what they take and what the return

[wary cloak]

Well for what they return that's easy

First two return a char and last one a char array

... Tho..

Since it's of unknown size actually a vector

pub fn getKey() -> char {
        todo!()
    }

    pub fn waitForKey() -> char {
        todo!()
    }

    pub fn getCharArray() -> Vec<char> {
        todo!()
    }

And about receiving

[coral geyser]

do you have Vec without std?

[wary cloak]

An instance of -

[wary cloak]

Oh no..

I mean it showed me no error so I ain't sure..

[coral geyser]

did you do a mod ...; in the main.rs

?

[wary cloak]

No, that error because of unused serial

Warning*

So since there's no error we are fine with vectors..?

[coral geyser]

so you didn't make it a module?

if it's not a module you won't get errors for it

[wary cloak]

Oh

...

It was better when I didn't import as a mod and it didn't have +9 errors(?

error[E0412]: cannot find type `matrix` in this scope
  --> src\Keypad.rs:4:13
   |
4  |     matrix: matrix
   |             ^^^^^^ help: a type alias with a similar name exists: `Matrix`
...
11 | type Matrix = [[char; 4]; 4];
   | ----------------------------- similarly named type alias `Matrix` defined here

error[E0412]: cannot find type `Pin` in this scope
 --> src\Keypad.rs:7:20
  |
7 | type ColumnPins = [Pin<OpenDrain, Dynamic>; 4];
  |                    ^^^ not found in this scope
  |
help: consider importing one of these items
  |
1 | use arduino_hal::port::Pin;
  |
1 | use core::pin::Pin;
  |

error[E0412]: cannot find type `OpenDrain` in this scope
 --> src\Keypad.rs:7:24
  |
7 | type ColumnPins = [Pin<OpenDrain, Dynamic>; 4];
  |                        ^^^^^^^^^ not found in this scope
  |
help: consider importing this struct
  |
1 | use arduino_hal::port::mode::OpenDrain;
  |

error[E0412]: cannot find type `Dynamic` in this scope
 --> src\Keypad.rs:7:35
  |
7 | type ColumnPins = [Pin<OpenDrain, Dynamic>; 4];
  |                -                  ^^^^^^^ not found in this scope
  |                |
  |                help: you might be missing a type parameter: `<Dynamic>`

error[E0412]: cannot find type `Pin` in this scope
 --> src\Keypad.rs:9:17
  |
9 | type RowPins = [Pin<Input<PullUp>, Dynamic>; 4];
  |                 ^^^ not found in this scope
  |
help: consider importing one of these items
  |
1 | use arduino_hal::port::Pin;
  |
1 | use core::pin::Pin;
  |

error[E0412]: cannot find type `Input` in this scope
 --> src\Keypad.rs:9:21
  |
9 | type RowPins = [Pin<Input<PullUp>, Dynamic>; 4];
  |                     ^^^^^ not found in this scope
  |
help: consider importing this struct
  |
1 | use arduino_hal::port::mode::Input;
  |

error[E0412]: cannot find type `PullUp` in this scope
 --> src\Keypad.rs:9:27
  |
9 | type RowPins = [Pin<Input<PullUp>, Dynamic>; 4];
  |                           ^^^^^^ not found in this scope
  |
help: consider importing this struct
  |
1 | use arduino_hal::port::mode::PullUp;
  |

error[E0412]: cannot find type `Dynamic` in this scope
 --> src\Keypad.rs:9:36
  |
9 | type RowPins = [Pin<Input<PullUp>, Dynamic>; 4];
  |             -                      ^^^^^^^ not found in this scope
  |             |
  |             help: you might be missing a type parameter: `<Dynamic>`

error[E0425]: cannot find value `rows` in this scope
  --> src\Keypad.rs:16:13
   |
16 |             rows,
   |             ^^^^
   |             |
   |             a field by this name exists in `Self`
   |             help: a local variable with a similar name exists: `row`

error[E0425]: cannot find value `columns` in this scope
  --> src\Keypad.rs:17:13
   |
17 |             columns,
   |             ^^^^^^^
   |             |
   |             a field by this name exists in `Self`
   |             help: a local variable with a similar name exists: `column`

error[E0412]: cannot find type `Vec` in this scope
  --> src\Keypad.rs:30:30
   |
30 |     pub fn getCharArray() -> Vec<char> {
   |                              ^^^ not found in this scope

Some errors have detailed explanations: E0412, E0425.
For more information about an error, try `rustc --explain E0412`.
error: could not compile `keypad` due to 11 previous errors

Ok the first I forgot the capital

About Matrix, what do we call it then?

[coral geyser]

Matrix is fine

[wary cloak]

it says there it already exist one called that

[coral geyser]

It's trying to be helpful and say what you probably ment

[wary cloak]

oh

so what about the others

use arduino_hal::port::Pin;
|
1 | use core::pin::Pin;

which of the two i need?

[coral geyser]

use arduino_hal::port::Pin;

considering that is what we have been looking at the docs for

[wary cloak]

what do i return in getCharArray? how do i do dibamic size arrays without vec, is malloc here a thing?

[coral geyser]

do you need it to be dynamic?

[wary cloak]

I want getCharArray to do the following

I want you to be able to write more than one char at a time and that it return all those characters as a char array , not a string because with a char array I can compare it with another index by index so when I do this password thing is going to be reaaaally useful

And I wanted to take as a parameter an interger to say

Ok I want a char array of size 5 because that how many characters long is the password

So you are available to write as much as you want

[coral geyser]

what if you set a max length of the password and use an array of that length?

[wary cloak]

Well that works too

So how do I say I give back a char array? Because about the max that's something of the implementation so I would see that later

[coral geyser]

how about ```
fn get_chars(&mut self, buffer: &mut [char]) -> usize {

}

[wary cloak]

eh..

I'm kind of confused

First what was usize?

[coral geyser]

usize is for counting things

[wary cloak]

Because for example that isn't giving me back a char array, and it's asking me a char array and I want to make one not ask for one so I don't understand at all

[coral geyser]

it's the size of the memory space

[wary cloak]

So..

Usize tells me the memory space something needs?

[coral geyser]

?eval 1usize

Ferris !!!

[wary cloak]

[coral geyser]

its just a number

[wary cloak]

And that number is the number of bytes of memory needed for a certain variable?

[coral geyser]

no

[wary cloak]

Then idk what it is but

Why are you return that and not a char array as the idea was?

Returning*

[coral geyser]

do you know about u8, u16, u32, u64, u128, i8, i16, i32, i64, i128?

the types of numbers

[wary cloak]

Eh I guess so, signed and usigned ints that have different ranges of numbers they can cover

[coral geyser]

usize is u16, u32, or u64 depending on the platform

[wary cloak]

So why not type just for example u16?

[coral geyser]

because indexing arr[index] expects a usize

[wary cloak]

It's weird that they are the same but aren't used for the same-

[coral geyser]

We are returning the chars, just not as the return value

[wary cloak]

A usize for the index?

[coral geyser]

yeah, because usize::MAX is the max number of things you could possibly have in memory

[wary cloak]

So it expectes to be have a limit size of for example u32?

[wary cloak]

How (?

[coral geyser]

buffer

we stuff them in buffer

[wary cloak]

And why are we giving a char array as a parameter if I want the char array to be created there and give it back?

[wary cloak]

Wdym by stuff?

[coral geyser]

the caller gives us a slice of chars, we put the chars the user types into it

then return how many the user typed

[wary cloak]

But why would I want to return how many he typed if that's not data I'm interested in?

[coral geyser]

so you know how many chars where replaced in buffer

[wary cloak]

Oh wait so.

My function getCharArray

Would recieve as a parameter a buffer to store what I write when calling it?

And also I was going to say that all functions would need to recieve the instance of my struct that has the relevant data but now that I think about that would be with a mutable reference to self so that's fine I understand that very first part

[coral geyser]

yep

[wary cloak]

But again why I would want to know that(?

The only thing I want

Is to write my characters and have all of them in a char array

How many, I don't care ig

[coral geyser]

what about when the user enters a new password?

[wary cloak]

So you say to also compare the lengths of the passwords?

[coral geyser]

well you can but thats not the main point

[wary cloak]

Then what is it

I know you can't return a char array I tried

[coral geyser]

so you know how long the actual password is

[wary cloak]

But that's what I want to do

[wary cloak]

I just care that the password I send and the on that would be compared to are equal, length doesn't matter excepting ofc for the fact that if it's longer or shorter is wron-

Oh

It return the size

So I can compare it to the maximum size I established

Right?

[coral geyser]

sorry, we went into overtime in my rocket league match, the size is needed because say buffer has length 15 chars. And the user types in 4 chars for the password. You need to know that the password in the buffer is only 4 of the 15 chars

Unless the password never changes

[wary cloak]

No need to apologize

Say I understand but

Oh

I understand

Since I borrow a mutable reference to buffer

By calling the function the buffer would have what I write to it

Ooh

Well so

We know the signature of this function now for the others

I think the only needed parameter would be an instance to hour struct that has all the important data, aka, a mutable reference to self, do you agree?

[coral geyser]

sure

[wary cloak]

Ok now I will send the remaining errors

Checking keypad v0.1.0 (C:\Users\fuchi\OneDrive\Documentos\Codigos_Rust\keypad)
error[E0412]: cannot find type `Dynamic` in this scope
 --> src\Keypad.rs:9:35
  |
9 | type ColumnPins = [Pin<OpenDrain, Dynamic>; 4];
  |                -                  ^^^^^^^ not found in this scope
  |                |
  |                help: you might be missing a type parameter: `<Dynamic>`

error[E0412]: cannot find type `Dynamic` in this scope
  --> src\Keypad.rs:11:36
   |
11 | type RowPins = [Pin<Input<PullUp>, Dynamic>; 4];
   |             -                      ^^^^^^^ not found in this scope
   |             |
   |             help: you might be missing a type parameter: `<Dynamic>`

error[E0425]: cannot find value `rows` in this scope
  --> src\Keypad.rs:18:13
   |
18 |             rows,
   |             ^^^^
   |             |
   |             a field by this name exists in `Self`
   |             help: a local variable with a similar name exists: `row`

error[E0425]: cannot find value `columns` in this scope
  --> src\Keypad.rs:19:13
   |
19 |             columns,
   |             ^^^^^^^
   |             |
   |             a field by this name exists in `Self`
   |             help: a local variable with a similar name exists: `column`

Some errors have detailed explanations: E0412, E0425.
For more information about an error, try `rustc --explain E0412`.
error: could not compile `keypad` due to 4 previous errors

[coral geyser]

you need to add a use ... for Dynamic

[wary cloak]

What use exactly?

I thought it would be in mode like that other but it wasn't

[coral geyser]

search in the docs for Dynamic

[wary cloak]

Mmm

It seems it isn't in pins

Neither in modes

Mode*

Ah there you are bastard

So..

use atmega_hal::port::Dynamic

?

[coral geyser]

yep

[wary cloak]

And what about the other errors?

[coral geyser]

the names are just wrong

[coral geyser]

"
a field by this name exists in Self
| help: a local variable with a similar name exists: row
"

[wary cloak]

If I put row and column

It says no such field

[coral geyser]

rows: row

[wary cloak]

?

[coral geyser]

in the struct you called it rows, in the function you called it row

[wary cloak]

And also the import failed

[wary cloak]

No it is rows

Because row says no such field

Rows says

Cannot find value in this scope

[coral geyser]

try use arduino_hal::hal::port::Dynamic;

[wary cloak]

It worked

error[E0425]: cannot find value `rows` in this scope
  --> src\Keypad.rs:19:13
   |
19 |             rows,
   |             ^^^^
   |             |
   |             a field by this name exists in `Self`
   |             help: a local variable with a similar name exists: `row`

error[E0425]: cannot find value `columns` in this scope
  --> src\Keypad.rs:20:13
   |
20 |             columns,
   |             ^^^^^^^
   |             |
   |             a field by this name exists in `Self`
   |             help: a local variable with a similar name exists: `column`

For more information about this error, try `rustc --explain E0425`.
error: could not compile `keypad` due to 2 previous errors

only this left

[wary cloak]

That one?

I don't understand why but ok

[coral geyser]

you put row there not rows

[wary cloak]

But that'st the name of the function parameter

Anyways now that everything works

We have the last more or less complicated task

Making the getKey function

[coral geyser]

it didn't match what you had here

[wary cloak]

We know the logic and there's my C example but my C example do it another way

So we will see how to do that function

Then waitForKey would call getKey inside but do it so it blocks

An getCharArray call it multiple times or smth and store the chars it receives

The point is, this is the last "key" Part

So how do we do it?

[coral geyser]

how about we add 2 helper functions

[wary cloak]

What were helper functions?

[coral geyser]

one to enable one of the columns and one to read a row

actually, doing it as one function will probably work better

[wary cloak]

Like I did in my C code?

[coral geyser]

functions that aren't pub

[wary cloak]

Oh I see

[coral geyser]

a function that checks one column row pair

fn check_row_col(&mut self, row: usize, col: usize) -> bool {
  ...
}

[wary cloak]

Why row and col of usize here?

And a bool to true if it finds a match?

[coral geyser]

because self.rows[row] can work nicely without casts

[wary cloak]

and what's inside the array rows is usize?

[coral geyser]

It will return true if the button at row, col is pressed

[wary cloak]

I thought they were the pins(?

[coral geyser]

rows is the pins

we index with a number

self.rows[0], self.rows[1], ...

[wary cloak]

Oh so it is one pair at a time but I guess we will call it in loop to for each iteration call a different row and column and so

[coral geyser]

yep

[wary cloak]

I declare this function below the getCharArray one still in the impl block?

[coral geyser]

yep

[coral geyser]

also functions are snake case

[wary cloak]

Oh I did them like in C++ sorry (?

Ok done

What do we write inside the new check function?

[coral geyser]

so first we need to set one of the output pins low

whichever col is

[wary cloak]

I thought we wouod start with an iterator or for

[coral geyser]

and make sure the rest are high

[wary cloak]

And then inside the for turn that one and then the other in the next iteration

Would"

[coral geyser]

for (i, pin) in self.columns.iter_mut().enumerate() {
  if i == col {
    pin.set_low();
  } else {
    pin.set_high();
  }
}

[wary cloak]

...

Explain it to me I understand it a 70% or so

[coral geyser]

we go through each column pin, and set all to high except for the column we want to check

[wary cloak]

So I would be the current pin

So like for pin 1,2,3,4 (example ) in

[coral geyser]

yep

[wary cloak]

Self.cols you wanted to say self.columns?

[coral geyser]

oh yeah

[wary cloak]

Turn it into an iterator so it is iterable

But way a mutable one?

Why*

[coral geyser]

so you can call set_low, set_high

those mutate the pin

[wary cloak]

Oh

And enumerate if I remember correctly..

Gave back a touple with the index and element at said index?

[coral geyser]

yep

[wary cloak]

Which is what you are iterating through so it makes sense

So if the current iteration of the loop is equal to the col sended set it high and the rest set them low

I understand

Ok so now we have set the col sended to high and the rest to low

I guess we will then in getKey

[coral geyser]

wait we didn't check the row yet

[wary cloak]

Call this function in a for loop to iterate to each posible row in a column and then the next column and so

[wary cloak]

Ik

[coral geyser]

yes we will

[wary cloak]

How do we check the row?

[coral geyser]

self.rows[row].is_low()

[wary cloak]

Remember me

Why row needed to be low

I remember column

If low was disconnected

And if high it was 0

And row..

It had 5v by default..

[coral geyser]

row is high by default

[wary cloak]

Oh

[coral geyser]

it goes low when connected to the column we set to low

[wary cloak]

So pressing it is low

[coral geyser]

yep

[wary cloak]

Tho we are asking there for what pin? All of them?

[coral geyser]

the pin for index row

we don't need to check the others

[wary cloak]

Oh yeah

So

I pass a certain col and row

I guarantee only the col I pass is high by setting it in any case

And I ask if the row I send is low for that col, right?

[coral geyser]

yep

[wary cloak]

And you said I would only see a 0, low, not when I press it but rather when I press it and also it matches with the col?

[coral geyser]

yep

because it only goes low if it gets connected to ground

which only the one output set to low can do

[wary cloak]

And it's ground because it's 0v?

[coral geyser]

yep

[wary cloak]

But also the other thing would be 0v

[coral geyser]

ground by definition is 0v

[wary cloak]

It's like two ground or smth

So now we go to get key where we would basically do a for loop using this function?

[coral geyser]

sort of related, https://www.youtube.com/watch?v=Bine_PbyFSQ

[wary cloak]

That explains why it works even tho the 2 are 0 volts?

[coral geyser]

its more a general how transistors work

[coral geyser]

yep

[coral geyser]

try doing that one by yourself first

[wary cloak]

Oh I am supposed to know but you know supposed even tho I still use them when I learnt about them it was pandemic

So I couldn't say if I know enough

[wary cloak]

But my answer is correct(?

Ok then let's see

Since the function waits for a usize

I pass as a parameter the index?

[coral geyser]

yep

[wary cloak]

pub fn get_key(&mut self)  {
        for (col, pin) in self.columns.iter().enumerate() {
            for (row, pin) in self.rows.iter().enumerate() {
                if self.check_row_col(row, col) == true {
                    return 
                }
            }
        }
    }

Two issues

First

Idk how to return

The key pressed

...

Mmm..

wait

I had an idea

Why not in matrix

Instead of 4,4

Do

Rows columns

So

[coral geyser]

||self.matrix[row][col] ||

[wary cloak]

I could call the matrix at the current row and col

[wary cloak]

What I thought but , would that work as it is right now? Shouldn't I change what I said?

[coral geyser]

why

[coral geyser]

not sure what you mean here

[wary cloak]

If it works as you said forget it(?

[coral geyser]

it should work as is

[wary cloak]

[coral geyser]

add a ; after the return and the continue is wrong

[wary cloak]

The error is the same

[coral geyser]

and then at the end of the function you need to return a default char

or .... use Option<char>

[wary cloak]

So it could return none if it never finds one

[coral geyser]

yep

[wary cloak]

Still

[coral geyser]

you need to return the None

[coral geyser]

also the continue is still wrong

[wary cloak]

Where?

[wary cloak]

Why?

[coral geyser]

At the end of the function just put None

[wary cloak]

If it doesn't match

Ask for the next

[coral geyser]

because it will only check the first row of each column

[coral geyser]

for that you just do ... nothing

[wary cloak]

And when it's done asking the rows then it goes to the next column iteration

[wary cloak]

Shouldn't it skip in the for it's used "for"?

[coral geyser]

okay it's not wrong, just not needed

[coral geyser]

yeah it will, my bad there

if ... {
...
}

behaves the same way

[wary cloak]

Anyways

You are right

Last issue

Borrow checker

Maybe I would need to use a smart pointer

But lemme run cargo check first

error[E0502]: cannot borrow `*self` as mutable because it is also borrowed as immutable
  --> src\Keypad.rs:28:20
   |
26 |         for (col, pin) in self.columns.iter().enumerate() {
   |                           -------------------------------
   |                           |
   |                           immutable borrow occurs here
   |                           immutable borrow later used here
27 |             for (row, pin) in self.rows.iter().enumerate() {
28 |                 if self.check_row_col(row, col) == true {
   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ mutable borrow occurs here

For more information about this error, try `rustc --explain E0502`.
warning: `keypad` (bin "keypad") generated 4 warnings
error: could not compile `keypad` due to previous error; 4 warnings emitted

[coral geyser]

ah, we need to use 0..len instead

for col in 0..self.columns.len() {
  for row in 0..self.rows.len() {
    ...
  }
}

[wary cloak]

Can you so len in columns and rows?

Now that I think about it

They are an array

So yeah

Dooone

So next wait_for_key

Can we easily just make something blockable?

[coral geyser]

loop {
  if let Some(key) = self.get_key() {
    return key;
  }
}

[wary cloak]

I mean I thought we were using nb::block

But I think that also works

[coral geyser]

we could do that if you want to

[wary cloak]

Nah if it's not needed

Well finally only one method left

get_char_array

Tho two quick questiona first

Do you know what firmware is? i heard is software that operates ok hardware or modifies hardware or smth like that, like drivers, but you know seemed like embedded development was also that

[coral geyser]

what you are making can be considered firmware

[wary cloak]

So my definition is correct?

[coral geyser]

firmware is usually characterized by being indirectly influenced by a user. In other words, its software that just makes hardware do stuff

[wary cloak]

And also

[coral geyser]

its also usually unchangeable or hard to change

[wary cloak]

What else so you know to make in rust aside from embedded development? Apps with yew? Web dev with tauri, dino or webAssembly?

do you*

[coral geyser]

You can use Rust for basically anything you want, I have done all the above in some form before

Games is a growing one

[wary cloak]

Because you know since embedded development is kinda hard to do as hobby, cheap, and stuff it's like I would have nothing else to do with rust , after finishing the original project and this re write the idea was starting my adventure to learn C++ to a decent extent while finishing my python course and Django project, when all of that is settle on wanna finally dive into the web development world and learn HTML, CSS and JS, because they seems base knowledge nowadays, for example when I saw the real time chat app with rust with I thought hey interesting it used them

So I thought well I could in that future use rust as my backend

Be it for webs or apps

I want to use rust and that's the only other idea I have (?

And also..

To be fair I don't know for sure if I would use rust embedded again until it grows an ecosystem good enough ig, or I should see

So well I wanted to know of someone who also knew

Is it easier or harder than this web development?

At least the rust ecosystem there should be a lot bigger

[coral geyser]

that would be better answered by #net-and-web , i don't do much web right now

[wary cloak]

Oh ok

Having said that

How so we begin the get_char-
_array function?

I guess we could

Enter a for loop for the len of the buffer

[coral geyser]

I need to go to bed 💤

[wary cloak]

And add to the index i so it changes which each iteration the result of calling getKey

[wary cloak]

Oh ok, guten natch and thanks for the help today

I will do maybe a small prototype or smth (maybe not) and leave it here

pub fn get_char_array(&mut self, buffer: &mut [char]) -> usize {
        for i in 0..buffer.len() {
            if let Some(key) = self.get_key() {
                buffer[i] = key;
            }
        }

        return buffer.len()
    }

More or less that

Idk if I have to deal with /0 here

I tried to do

buffer[i] = '/0'

Below for loop but it didn't let me do it so

And also I know I'm not properly giving back the len of the actual used buffer and all that but this is kinda prototype to see how to better this later

[old mango]

Btw it's \0, not /0, although idk the api requires NUL termination or no

[wary cloak]

Well I'm used to the C way that all strings ends with the end string character therefore char arrays too

So idk if here I have to mark the end of the string with said character or not

[wary cloak]

Good afternoon @coral geyser are you available?

[coral geyser]

yep

[wary cloak]

Ok then today likely we can finish this project

[wary cloak]

This is what I thought tho there's likely more job to do

But for the time being, is it fine for now?

[coral geyser]

wont this just instantly fill up the buffer with the same char

because get_key doesn't wait

[wary cloak]

I didn't understand that at all the idea was for it to start the loop, click get key, if it's the some variant and to the current index them move to the next and you know

And then return buffer.len() just for the compiler not to shout at me

[coral geyser]

but you need to wait for no key being pressed between checking for the key pressed

[wary cloak]

Would the be fixed by making the exact same thing but with wait for key without the need for a if let.

*?

[coral geyser]

otherwise you will just get something like
aaaaaaaaaaaaaaaaaaaaaaa

[coral geyser]

no, because we need to wait for a key pressed, and no key pressed

[wary cloak]

So I replace get key with wait for key leaving the if let as it is?

Because

Wait for key return a char not an option char

[coral geyser]

we need something like

let mut index = 0;
loop {
  match self.get_key() {
    None => { /* no key pressed just check again */ }
    Some('a') => {
      // enter key pressed (here I use 'a' for enter)
      // we don't write the char to the buffer and return what we have written
      return index;
    }
    Some(key) => {
      // put key in the buffer
      buffer[index] = key;
      // move to the next char in the buffer
      index += 1;

      // check if we reached the end of the buffer
      if index == buffer.len() {
        return index;
      }
      
      // wait for key to be not pressed
      while let Some(_) = self.get_key() {}
    }
  }
}

[wary cloak]

I didn't understand at all(?

Why are we using a loop instead of a for?

[coral geyser]

because we are waiting for the user to press a specific key to stop

[wary cloak]

So we will tell him that he can write as much as he wants and then use a key to finish the loop?

[coral geyser]

yep

though we probably want to stop it before the user writes more than the size of buffer

[wary cloak]

So we have a mutable variable index to know how long is the array and also

For indexing

[coral geyser]

for index in 0..buffer.len() {
  match self.get_key() {
    None => { /* no key pressed just check again */ }
    Some(key) => {
      // put key in the buffer
      buffer[index] = key;
      
      // wait for key to be not pressed
      while let Some(_) = self.get_key() {}
    }
  }
}

would be the version for a fixed input size, aka the user always has to type in the amount buffer expects

[coral geyser]

yep

[wary cloak]

So we use a loop so he's not forced to write a set amount nor less neither more?

[coral geyser]

yeah, though we can do the first version as a for loop also

[wary cloak]

Now I don't understand the first match so.

[coral geyser]

for index in 0..buffer.len() {
  match self.get_key() {
    None => { /* no key pressed just check again */ }
    Some('a') => { return index; },
    Some(key) => {
      // put key in the buffer
      buffer[index] = key;
      
      delay_ms(100); // delay to debounce input

      // wait for key to be not pressed
      while let Some(_) = self.get_key() {}
    }
  }
}
buffer.len()

[wary cloak]

We call get for key and match it to the none variant and some variant

With an specific key

So if there's nothing pressed yet

Just keep going and asking

But if the specific key is presses end the loop and return the index so we know how long is the char array

Oh they are from the same match

I get it now

[coral geyser]

maybe we should add

// wait for key to be not pressed
while let Some(_) = self.get_key() {}

to wait for key

that would simplify this somewhat and help in other spots

[wary cloak]

And if another key is pressed it would be bind to "key" and stored in the current index of the buffer, then b
Index+1, and of that index is already the length of the buffer we go back

Now I just don't understand the last part of while let

Let me see if I understand

While the Some variant isn't an underscore (none I would suppose) it will keep going, since it's a while it will stay there and it needs a {}

It's that correct?

[coral geyser]

_ in a pattern means: "something but I don't care about it"

[wary cloak]

Then I don't understand how that line works

How does that waits until nothing else is pressed

Wait*

[coral geyser]

what does get_key return when no keys are pressed?

[wary cloak]

none

[coral geyser]

Does None match Some(_)?

[wary cloak]

Eh I guess so but that also matches any other pressed key

Why not ask for None?

[coral geyser]

we could do it as

while !matches!(self.get_key(), None) {}

[wary cloak]

But I want to be able to understand the one above first

[coral geyser]

the while loop spins in the {} while the condition is true

[wary cloak]

Oh so

If whatever key is pressed

It continues

I don't care which key

That's why _

But when none is there it won't match and I know it's not pressed

Excellent

Now..

[wary cloak]

Explain this (?

[coral geyser]

matches!() takes a value (self.get_key()) and checks if it matches the pattern (None) if it does match it returns true

[wary cloak]

So the other ! It's so that when it return true it's false and it breaks the loop

Both of them are cool so idk which one to use..

Which one you think is cooler or you prefer?

[coral geyser]

I like the while let one

[wary cloak]

Oh ok

So here it's the function up until now

pub fn get_char_array(&mut self, buffer: &mut [char]) -> usize {
        let mut index = 0;
        loop {
            match self.get_key() {
                None => { /* no key pressed just check again */ }
                Some('#') => {
      // enter key pressed (here I use 'a' for enter)
      // we don't write the char to the buffer and return what we have written
                return index;
    }
                Some(key) => {
      // put key in the buffer
                    buffer[index] = key;
      // move to the next char in the buffer
                    index += 1;

      // check if we reached the end of the buffer
                    if index == buffer.len() {
                        return index;
                }
      // wait for key to be not pressed
                    while let Some(_) = self.get_key() {}
            }
        }
    }
}

Is it done?

[coral geyser]

I think we should move

// wait for key to be not pressed
while let Some(_) = self.get_key() {}

to wait for key

That will make wait for key behave better

[wary cloak]

pub fn wait_for_Key(&mut self) -> char {
        loop {
            if let Some(key) = self.get_key() {
                return key;
            }
        }
    }

In which part?

[wary cloak]

Btw, is it?

[coral geyser]

yeah

[wary cloak]

.

[coral geyser]

pub fn wait_for_Key(&mut self) -> char {
    loop {
        if let Some(key) = self.get_key() {
            delay_ms(100); // debounce the key

            // wait for key to be not pressed
            while let Some(_) = self.get_key() {}
            
            return key;
        }
    }
}

Is what I am thinking

[wary cloak]

Tho I don't get why is it needed

[coral geyser]

this will make wait for key wait for a single press then release

[wary cloak]

So we aren't only dealing which short circuit but also

"Anti-rebote"idk how you call that in English

[coral geyser]

Anti-bounce

or debounce

[wary cloak]

How did you actually write the delay?

[coral geyser]

well delay_ms is in arduino_hal::delay_ms

[wary cloak]

That