Due to high demand and inclement weather, expect some shipping delays at this time, orders may not ship for 4-5 business days.
0

is31fl3731 With Pimoroni Led Shim
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

is31fl3731 With Pimoroni Led Shim

by Toldcodger on Tue Nov 30, 2021 6:23 pm

Hi,
I’m trying to get the CircuitPython is31fl3731 LedShim Rainbow example to run on a Pico.
I get various error such as SDA not defined and No pull-up resistors found. I added a2.2k resistor to the sda and scl lines but it made no difference.

I am using GP0 and GP1

Toldcodger
 
Posts: 28
Joined: Mon Nov 04, 2019 4:52 pm

Re: is31fl3731 With Pimoroni Led Shim

by mikeysklar on Thu Dec 02, 2021 7:33 pm

Post your code and errors in CODE blocks please.

This sounds like you need to modify the Pico specific pins naming conventions.

https://learn.adafruit.com/getting-star ... on/pinouts

mikeysklar
 
Posts: 6570
Joined: Mon Aug 01, 2016 8:10 pm

Re: is31fl3731 With Pimoroni Led Shim

by Toldcodger on Fri Dec 03, 2021 4:28 pm

Hi,
Thanks for the response.
i started by using the is31fl3731_ledshim_rainbow.py script from the circuitpython examples folder. That's when I got the SCL not defined error. I did a little digging and found this,
https://learn.adafruit.com/getting-star ... on/pinouts
Basically it says;
import board
i2c = board.I2C() # Does not work on the Pico.
Try this
import board
import busio
i2c = busio.I2C(scl=board.GP1, sda=board.GP0)

I've attached the file I modified. The original file is identical apart from this line:
i2c = busio.I2C(board.SCL, board.SDA)
Attachments
is31fl3731_ledshim_rainbow.py
(1.13 KiB) Downloaded 3 times

Toldcodger
 
Posts: 28
Joined: Mon Nov 04, 2019 4:52 pm

Re: is31fl3731 With Pimoroni Led Shim

by Toldcodger on Fri Dec 03, 2021 4:38 pm

Sorry,
I forgot to show the full error:

Traceback (most recent call last):
File "<stdin>", line 9, in <module>
RuntimeError: No pull up found on SDA or SCL; check your wiring

Toldcodger
 
Posts: 28
Joined: Mon Nov 04, 2019 4:52 pm

Re: is31fl3731 With Pimoroni Led Shim

by mikeysklar on Sat Dec 04, 2021 7:09 pm

Yep, you got the right syntax now for the i2c pins.

Can you post a photo of how you have connected the SHIM to the Pico? It seems like it might not be connected to the proper pins.

mikeysklar
 
Posts: 6570
Joined: Mon Aug 01, 2016 8:10 pm

Re: is31fl3731 With Pimoroni Led Shim

by Toldcodger on Sun Dec 05, 2021 7:39 am

I’ve added a photo of the ledshim and Pico. The photo shows it set for 5v but i’ve tried it with 3.3 with the same results.

The ledshim is on a double row of pins as it would be on a RPi. I’ve checked for continuity and cross connections, everything is fine.

As the shim literally slots on the gpio pins, I’m wondering if it’s just a poor connection. When my Grandson goes home I’ll try soldering the connections on the ledshim.
Attachments
975F3138-27CE-45A2-B3FA-60DF46964944.jpeg
975F3138-27CE-45A2-B3FA-60DF46964944.jpeg (756.57 KiB) Viewed 116 times
12F4A8D6-F608-48C3-BB86-5BCD20ED0D20.jpeg
12F4A8D6-F608-48C3-BB86-5BCD20ED0D20.jpeg (652.12 KiB) Viewed 116 times

Toldcodger
 
Posts: 28
Joined: Mon Nov 04, 2019 4:52 pm

Re: is31fl3731 With Pimoroni Led Shim

by mikeysklar on Sun Dec 05, 2021 3:24 pm

I have not seen anyone try to use the LED shim with a pico only a Raspberry Pi based board, but it's i2c so should be possible.

You will want to keep the voltage at 3v3 to avoid damaging your Pico.

You posted an image of a Raspberry Pi pinout, but you are using a Pico Pi which is not the same.

At this point I'm going to refer you over to the Pimoroni forums as they support the usage of their hardware.

http://forums.pimoroni.com/

Screen Shot 2021-12-05 at 11.20.50 AM.png
Screen Shot 2021-12-05 at 11.20.50 AM.png (177.31 KiB) Viewed 111 times

mikeysklar
 
Posts: 6570
Joined: Mon Aug 01, 2016 8:10 pm

Re: is31fl3731 With Pimoroni Led Shim

by Toldcodger on Sun Dec 05, 2021 4:49 pm

Thanks for your assistance mikeysklar.
I posted the pinouts for the ledshim to show that I had taken the correct connections for the sda & scl connections.

I found some code on the Adafruit site to get the I2C address. That doesn’t work either and comes back with an I2C not defined error. I have used an I2C display on the GP0 & GP1 pins so I will try that again tomorrow to prove those pins work. I’ll try the I2C detector code too.

I tried to get a Pimoroni Blinkt working on the Pico. The problem with that is getting a 102apa library for either micropython or circuitpython. Someone on there said I needed to use 3.3v. Another responder said the Raspberry Pi is 3.3 logic and the Blinkt works OK on the Pi so 5v won’t cause a problem on the Pico. I presumed the LEDshim would be the same. I have tried using 3.3v but got the same errors.

Toldcodger
 
Posts: 28
Joined: Mon Nov 04, 2019 4:52 pm

Re: is31fl3731 With Pimoroni Led Shim

by mikeysklar on Mon Dec 06, 2021 5:30 pm

@Toldcodger,

You need to start a thread with Pimoroni on connecting a Pico with their LED Shim. Pimoroni handles their own hardware support.

The Pico is not 5v tolerant on the i2c pins so 5v is a bad idea. Keep it 3v3.

mikeysklar
 
Posts: 6570
Joined: Mon Aug 01, 2016 8:10 pm

Please be positive and constructive with your questions and comments.