#ATtiny8x7 breakout question

1 messages · Page 1 of 1 (latest)

grave quest
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Threading!

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Ok, so SCL and SDA. The pins.

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@viral sphinx oh tagging you, in case the thread isn't obvious.

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Ok, SCL/SDA. Not the STEMMA connectors.

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Are they clock and data pins for I2C?

viral sphinx
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👋

grave quest
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Or are they something else technically?

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They're vaguely called "address pins" in the product copy

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so I'm now second guessing my pinouts explanation

viral sphinx
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one sec. let me look.

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there are address pins and an interrupt pin

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that explains why no digital io on 14/15/16 (i think)

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i think on pin numbers...but can check

grave quest
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15-17

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I just had this conversation with Limor

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so how do I explain this? 😕

viral sphinx
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yep. those are special pins.

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could probably argue silk should be something other than the numbers

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15 = INT
16 = ADDR0
17 = ADDR1

grave quest
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Oh ok

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so like the ADR pins on the original board?

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    16 / AD0 - this is the ADDR0 pin. Connect this to ground to increment the devices I2C address by 1.
    17 / AD1 - this is the ADDR1 pin. Connect this to ground to increment the devices I2C addres by 2.
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or...?

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I don't even know what that means, heh

viral sphinx
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i think that info is original guide?

grave quest
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Ok

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I'll take a look

viral sphinx
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they probably add to a base value

grave quest
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at least I know I have it wrong so far

viral sphinx
grave quest
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Yeah that's what I pasted above

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from that spot in the original guide

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Ok, thanks Carter. I'll see to updating the pinout explanations.

viral sphinx
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it'd be worth having a little table or something to just say what they are

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ok...looking at SCL/SDA pins now...one sec...

grave quest
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I'm doing the same style pinouts page as original

viral sphinx
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they're just the same pins as the stemma connector

grave quest
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No they're not...

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STEMMA is 10 and 11

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so says product copy I think

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That's what made me ask

viral sphinx
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i'm looking at pcb in eagle

grave quest
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So am I now, and I'm more confused than before.

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oh

viral sphinx
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it's like other STEMMA breakouts

grave quest
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the pin numbers don't match the chip pins

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sigh

viral sphinx
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you can use either the STEMMA connector or the headers

grave quest
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Ok ok ok ok

viral sphinx
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Two STEMMA QT I2C connectors with 10K pullup resistors, connected to pins 10 and 11
grave quest
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That's not right

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it's 11 and 12.

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According to the schematic

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but there's all kinds of problems with that product copy

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I'll need to get Limor a list.

viral sphinx
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the numbers may be the arduino pin numbers

grave quest
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checking

viral sphinx
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11/12 are the phyiscal pin numbers on the JP3 header

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16/15 physical pins on the attiny

grave quest
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Isn't that what I should be listing is the silk?

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oi.

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(forgot for a moment this is a public thread.)

viral sphinx
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the arduino core is what maps these to different numbers

grave quest
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Then what is CircuitPython doing?

viral sphinx
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see how physical pin 24 is 18

grave quest
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Yes

viral sphinx
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and PA01 etc

grave quest
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Yes

viral sphinx
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the core does that

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and...i'm...not actually sure where the core is...tbh

grave quest
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yeah........

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this is so confusing again.

viral sphinx
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here's an example from the SAMD core

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for feather m4

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0 would be the first entry in that table

grave quest
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Yeah.

viral sphinx
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1 the next, etc

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so somewhere there's a similar thing for the attiny8x7 that maps PA01 (phyiscal pin 24) to 18

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at least i think there is

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and in there, the SCL/SDA pins would be the 10 and 11 entries in the table

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thus the product page verbiage

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(this is my guess)

grave quest
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sigh.

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I don't want to keep bugging Limor about this. But I guess I should.

viral sphinx
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can wait a bit. let me look a little more.

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but the PCB file doesn't lie in terms of what the SCL/SDA pins are attached to - so they are just the STEMMA connector pins broken out again

grave quest
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Ok.

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So you could use the pins to connect to a micro

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if you wanted

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like any other breakout

viral sphinx
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yep. don't need to use the STEMMA connector.

grave quest
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ok

viral sphinx
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yep. like other breakouts.

grave quest
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not going to show that

viral sphinx
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just options

grave quest
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but trying to understand

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wait

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it's flashed with seesaw firmware

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that's what must be mapping things

viral sphinx
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correct

grave quest
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right?

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not ArudinoCore

viral sphinx
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but the firmware is just an arduino sketch

grave quest
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oh seriously?

viral sphinx
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the core is used to build the sketch

grave quest
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ohhhh

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There's an avr core, but it's not in there

viral sphinx
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that's essentially the firmware for the board

grave quest
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ok..

viral sphinx
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there's very little code there, since all the work is down in the other files

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the hack being done is putting code in header files

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i think she mentioned this on a desk-of way back

grave quest
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Ah

viral sphinx
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it's just a C compiler limitation hack thing

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because there's a desire to be able to configure things via #defines

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like at the top of the sketch

grave quest
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Oh she pasted this code to me earlier. Or rather four lines of it.

viral sphinx
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and then just build and be done

grave quest
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Ok

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oi.

viral sphinx
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but...there are C quirk things...so the hack (code in header files)

grave quest
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right

viral sphinx
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the real code is in all the .h files in the root dir

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of the repo

grave quest
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hmm yeah.

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I mean, should I ask Limor what pins she wants used on the pinouts page? Silk or ATtiny? Or is that a red herring on my part

viral sphinx
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the one .cpp there is just to keep the compiler happy. it's just an empty shell essentially.

grave quest
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Looking at the product copy

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for the other types of pins listed

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looks like silk.

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Oh there's separate addr selection pins: 2 x I2C address selection pins - pins 16 and 17

viral sphinx
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yep. silk is the arduino numbers.

grave quest
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But like, activity LED, pin 5.

viral sphinx
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18 for example

grave quest
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Ok, I'll use silk then.

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Which I guess means not pointing out what pins SCL/SDA are even connected to in the first place.

viral sphinx
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nah, you should

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you could describe those just like any STEMMA breakout

grave quest
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I'm confused

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They're SCL/SDA on the silk. I don't explain that pin 20 is 3........

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So why go further with those two?

viral sphinx
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let me read those other "uses" (the 3 in 1 stuff)

grave quest
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oki

viral sphinx
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 you could use it as either an I2C controller or peripheral with plug-and play support
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hmm....not sure i've looked into what the "controller" option here is

grave quest
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So I should list all of the ATtiny pins?

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That's what's confusing me at this moment. Why only SCL/SDA?

viral sphinx
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they may come into play when used as a controller....but not sure

grave quest
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hmm

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ok

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I think Limor expects folks to use it as a seesaw

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but she made it so she could use it for other things.

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Is my guess from the tone of the copy

viral sphinx
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yah, i understand use case 1 and 2, but not 3

grave quest
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um

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I guess you could use it as an ATtiny817 micro with an I2C sensor wired up to it?

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controller vs peripheral

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Have to power it via throughhole but ...

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I think that's what it means?

viral sphinx
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could be. that implies you'd load your own firmware. which may be. the UPDI pin is broken out.

grave quest
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It says you can do whatever you want with it at the bottom

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there's a core listed there.

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hah

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Guess I could have read more carefully

viral sphinx
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compiled using the megaTinyCore

grave quest
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I kind of checked out by the end of the seesaw pins

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I found that core when searching, but figured I was off base

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guess not

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Ok, so at this point, I guess I have a better question to ask Limor - do you want me to list both the silk pins and the ATtiny pins, or only the silk pins?

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Or are we still figuring this out

viral sphinx
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just silk pins is my guess

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anyone wanting attiny pins would use schematic

grave quest
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I mean I feel like at this point it comes down to what folks are going to do with this thing

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ok

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I'll go with that then.

viral sphinx
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but i think worth asking limor exactly what (where) the megaTinyCore she used is

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and link it in guide

grave quest
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I think it's linked later?

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in the copy

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second to last paragraph maybe?

viral sphinx
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only seeing link to the sketch

grave quest
viral sphinx
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ooohhh...ok...see it

grave quest
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Screenshot took too long

viral sphinx
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text is odd

grave quest
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had an arrow and everything.

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Imma send it anyway.

viral sphinx
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duh. yah.

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ok. let me look in there for stuff.

grave quest
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My computer likes to take arbitrary amounts of time to save screenshots, up to 5 minutes. It's great.

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Ok

viral sphinx
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mac?

grave quest
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Yep.

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I can get rid of the delay entirely

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but not make it be quick like it used to be

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Gets better after reboots, but then does this oscillating timing thing...

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Over time.

viral sphinx
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first column is silk

grave quest
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Oh ho.

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They're sort of right?

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LED is on 5 on this one...

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or

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looks

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nm.

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wait

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Yes I'm right.

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LED Is on 5 on the silk.

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pin 6 of the connector... but I don't think that's what it's referring to?

viral sphinx
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yah, ignore that LED

grave quest
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oki

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I guess the rest follows

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I mean, it's not as bad as RP2040, but it's getting there.

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oops, address selection pins not mentioned.

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Not sure how to tell which is which.

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and which does which

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Assume they're the same?

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and paste it from the original?

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nothing coming up in the datasheet.

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for addr0, ad0

viral sphinx
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the address and interrupt are entirely seesaw features

grave quest
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ohhhhh

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Got it

viral sphinx
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for the attiny arduino core, they are just gpio

grave quest
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it's in the sketch

viral sphinx
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seesaw makes special use of them

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yep. in the sketch.

grave quest
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#define CONFIG_ADDR_0_PIN          16
#define CONFIG_ADDR_1_PIN          17```
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ok

viral sphinx
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^^ yep

grave quest
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Thank you!

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I think this is a good pinouts page now.

viral sphinx
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3 addresses, so yah, it's like a 2 bit number that gets added to the base address

grave quest
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No idea if that note about speed is useful, but it's accurate. So... eh.

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Figure someone will complain at some point without it. Limor can delete it if she doesn't like it. 😄

viral sphinx
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yep. just copy pasta the address description for now. like it doesn't mention grounding both to increment by 3.

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but neither did the other guide

grave quest
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I did exactly that.

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Can you take a gander?

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Or a goose I guess.

viral sphinx
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you may want to mention that 15/16/17 can not be used as GPIO

grave quest
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Though geese are terrible. Goslings are cute though.

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Ok

viral sphinx
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worth a callout even probably

grave quest
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I made a note after the GPIO pins section.

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It's not colored

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should I make it an alert?

viral sphinx
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Note that pins 15, 16 and 17 can NOT be used as GPIO pins! with the seesaw firmware

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it's only an issue with the seesaw firmware

grave quest
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Oh right

viral sphinx
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they could be GPIO if someone wanted to do option 3

grave quest
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Riiight.

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ok updated to alert and wording is more accurate now

viral sphinx
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i'd make it color box

grave quest
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blue already

viral sphinx
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given the silk doesn't indicate it

grave quest
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Yah

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Anything else?

viral sphinx
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pinout page looks good

grave quest
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This chip seems like a better option than the SAMD09. Pin-wise anyway. No reset button might be annoying....

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Thank you

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whew.

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You were immensely helpful, I really appreciate it

viral sphinx
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sure. np.

grave quest
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One of these days I'll be in your neck of the woods, and I owe you a beverage of your choice.

viral sphinx
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i learned to. finally figured out where the core being used was.

grave quest
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excellent.

viral sphinx
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yeah BOYC!