touchpad | adafruit | Page 1

celest ember Feb 16, 2022, 2:13 AM

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also unplugging for a few minutes vs overnight should make no difference

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what version of CPy are you using?

unborn rain Feb 16, 2022, 2:14 AM

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adafruit-circuitpython-raspberry_pi_pico-en_GB-7.1.1

celest ember Feb 16, 2022, 2:16 AM

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that should be fine

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could you upload your program? Use the + on the left

unborn rain Feb 16, 2022, 2:17 AM

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📎 i2c_touchpad_code.txt

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maybe i spoke too soon I just tried to nuke it and it didn't reset the error

celest ember Feb 16, 2022, 2:20 AM

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you're powering the track pad from a GPIO pin?

unborn rain Feb 16, 2022, 2:20 AM

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ya so I can cycle power to the trackpad before starting my I2C connectionnn

celest ember Feb 16, 2022, 2:22 AM

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looking up something in the datasheet...

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the default drive strength of a GPIO pin on an RP2040 is only 4mA. Have you tried this when powering directly from 3.3V?

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and 5mA may be typical consumption, but if there are surges of consumption (like maybe when you are touching the pad), then the voltage could dip.

unborn rain Feb 16, 2022, 2:30 AM

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I have tried with using the 3.3 pin, but was having this issues, which is why I switched.

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l just looked up the active usage of the trackpad and it's 2.9 mA

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when I say this issue I mean the resistor error

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but their maybe multiple reasons for it

celest ember Feb 16, 2022, 2:32 AM

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if the I2C on the touchpad gets confused, then it could pull down the SCL or SDA lines (prob SDA) indefinitely, and then that would cause that error

unborn rain Feb 16, 2022, 2:32 AM

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but cycling power should fix the issue?

celest ember Feb 16, 2022, 2:32 AM

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we have seen this with various I2C sensors. They get wedged and hold down SDA indefinitely.

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It should

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there is no reset line, hunh, hmm

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what is "DR"

unborn rain Feb 16, 2022, 2:33 AM

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and what you are describing is exactly why I put the power on a gpio pin

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dr is data status

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as in data ready to read

celest ember Feb 16, 2022, 2:36 AM

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are R7 and R8 in place on your touchpad?

unborn rain Feb 16, 2022, 2:38 AM

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only resistor I have removed is R1

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I am lookign over the board though

celest ember Feb 16, 2022, 2:39 AM

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and you still have the 10k pullups?

unborn rain Feb 16, 2022, 2:39 AM

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4.7 k

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I found r7 and r8 they are on their

celest ember Feb 16, 2022, 2:46 AM

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looks like strong drive strength is on, so the power pin has 12mA drive

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I'm at a loss. If you had some other CircuitPython boards (not RP2040), I'd suggest trying one of those. The I2C problems you are seeing are unusual, and I'd suspect something unusual about the trackpad

unborn rain Feb 16, 2022, 2:48 AM

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I also tried the itsy bitsy as you previously suggested

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it worked for a while

celest ember Feb 16, 2022, 2:48 AM

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itsy bitsy what?

unborn rain Feb 16, 2022, 2:48 AM

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m4 express

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but it showed the same resistor error after a while

celest ember Feb 16, 2022, 2:49 AM

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that should be fine; this "worked for a while" business, and so forth is very odd, and I cannot explain it, except to blame the trackpad

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are you still using soldered connections, or did you wire it up on a breadboard?

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i would suspect a mechanical issue possibly as well (soldering, etc.)

unborn rain Feb 16, 2022, 2:52 AM

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I add the pin header to the pico, and added the female end to my touch pad wires. I should add I don't have 1 touch pad, but 3, I have wired them all up, and I have added the header to multiple picos,

celest ember Feb 16, 2022, 2:52 AM

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have you tried their arduino software on either the itsy or the RP2040

unborn rain Feb 16, 2022, 2:52 AM

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I tried the arduio on a teensey

celest ember Feb 16, 2022, 2:52 AM

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it should work on either of the other two with just pin changes

unborn rain Feb 16, 2022, 2:53 AM

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but when I tried to compile on a pico i ran into an errors I couldn't figure out

celest ember Feb 16, 2022, 2:53 AM

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the m4 would be more "standard". You still need to download our board support package. You can see the itsy guide for more info

unborn rain Feb 16, 2022, 2:55 AM

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what do you mean by a board support package ?

celest ember Feb 16, 2022, 2:56 AM

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arduino out of the box only supports mostly Arduino boards. For boards from other mfrs, you need to set a URL in the Preferences, and then download the Board Support Package for the mfr's fmaily of boards

unborn rain Feb 16, 2022, 2:56 AM

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oh I yes I downloaded the Pico support package

celest ember Feb 16, 2022, 2:56 AM

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This is all explained here: https://learn.adafruit.com/introducing-adafruit-itsybitsy-m4/setup

unborn rain Feb 16, 2022, 2:56 AM

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oh, your talking use Arduino on the m4 express

celest ember Feb 16, 2022, 2:57 AM

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for Pi Pico, it's a bit more complicated, and we have a guide: https://learn.adafruit.com/rp2040-arduino-with-the-earlephilhower-core

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make sure you set the board, etc.

unborn rain Feb 16, 2022, 2:57 AM

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ok, I am going to bed, thanks for the info

celest ember Feb 16, 2022, 2:58 AM

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good night!

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these are cheap enough, maybe I will order one or two to test

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you could also try using SPI instead of I2C

unborn rain Feb 16, 2022, 3:02 AM

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I thought of that, but then I would have to restart from scratch as I don't know the first think about SPI

celest ember Feb 16, 2022, 3:22 AM

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perhaps there is also an issue with the trackpad going to sleep at inopportune times

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there are some humidity sensors that go to sleep and you have to probe them to wake them up again.

unborn rain Feb 16, 2022, 11:14 AM

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If that were the issue. Unplugged it and plugging back it I would think would solve the issue at least temporarily

unborn rain Feb 17, 2022, 2:44 AM

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I read in an Arduino post someone had to manually toggle the pull down resistor to get it to start working. Is there a way for me to try this in circuit python? https://electronics.stackexchange.com/questions/228270/i2c-communication-wont-start-unless-sda-pullup-resistor-is-reinserted

Electrical Engineering Stack Exchange

I2C communication won't start unless SDA pullup resistor is reinserted

I'm working on a project where a PIC12LF1552 microprocessor is using I2C to talk to a TMP75 temperature sensor. Like the title says, a very strange issue keeps happening.

Overview

Every time I p...

celest ember Feb 17, 2022, 3:55 AM

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I think that problem is peculiar to that sensor. It's not true in general for I2C.

celest ember Feb 19, 2022, 8:10 PM

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From @unborn rain: Just wanted to let you know that I think I have the Trackpad working now. I have done two things. I plugged the trackpad back into the 3.3 v pin, rather then gpio, and I am not running Mu. I left it plugged in for a number of hours and it is still working, where as before it would only last a couple of minutes before kicking up an error.

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Glad to hear! I am not sure why leaving it connected to Mu would make any difference, but that may not have been the ultimate fix.

unborn rain Feb 19, 2022, 8:14 PM

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I was having other issues with mu, specific related to using serial connection. Maybe it is just power, will be able to test further later. For now I have a solution

unborn rain Feb 20, 2022, 2:05 AM

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Proof! It total it is MU! I just started up MU, and instantly the program failed, where it had been running flawlessly for hours...

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well that makes it hard to program and debug

celest ember Feb 20, 2022, 2:00 PM

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What exactly happens when it fails? What version of Mu are you using? What is your host computer and OS? And if you start the program with the Mu serial window open, do you see any errors printed?

#touchpad