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NeoTrellis 8x8 Kit - Maybe DOA Neotrellis boards
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Please be positive and constructive with your questions and comments.

NeoTrellis 8x8 Kit - Maybe DOA Neotrellis boards

by imnotjames on Sat May 21, 2022 12:15 pm

Order 2845210-3721189948
Neotrellis 8x8 Kit with Feather M4 - https://www.adafruit.com/product/1929

I'm trying to figure out if these boards are bad, if I did something to damage them, or if there's something else I'm missing.

After receiving the kit, I made the mistake of only testing one of the boards with the circuit playground. We soldered the boards, and while the solder joints could have been better I was able to confirm with a multimeter that all of them made connections.

Image

However, once the board was assembled, the code in the example didn't work as expected. Hooking up the serial I saw the error message as such:

Code: Select all | TOGGLE FULL SIZE
No I2C device at address: 0x2e


I checked all of the solder joints, tried a few different stemma plug points on the boards, no luck.

I updated the code to instead print out an I2C bus scan.

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import time
import board
from board import SCL, SDA
import busio

i2c_bus = busio.I2C(SCL, SDA)
i2c = i2c_bus
while not i2c.try_lock():
    pass

try:
    while True:
        print(
            "I2C addresses found:",
            [hex(device_address) for device_address in i2c.scan()],
        )
        time.sleep(2)
finally:
    i2c.unlock()


No matter what board I plugged into this always listed out only `0x30` and `0x31` - even when I was plugged into `0x2E`! So the board itself was fine but the I2C wasn't enumerating.

I checked again with the multimeter, and after some chatting on the adafruit discord I decided to pick up 2 more neotrellis boards since my guess was that these two were no good. Worst case, I'd end up with 2 extra cool boards. The horror. :)

So, those arrived and THIS TIME I tested them before soldering anything. Both of the new boards worked! I desoldered the two old boards that weren't working and set up the two new boards. Everything worked perfectly, and I was able to assemble the kit and play with it. This time I even used my new flux pen I bought from adafruit and everything looked so much nicer.

But that leaves the two other boards. I desoldered everything from them and un-did the shorted addressing pins.

I hooked them up to the playground in the same way that I did the new boards that I'd tested and no luck!

Code: Select all | TOGGLE FULL SIZE
I2C addresses found: []


Image

Is there anything else I can do to debug these? Are they DOA? ):

imnotjames
 
Posts: 4
Joined: Wed Jan 05, 2022 2:47 pm

Re: NeoTrellis 8x8 Kit - Maybe DOA Neotrellis boards

by dastels on Sat May 21, 2022 1:27 pm

I would first clean off the solder on the edge pads and check that there are no shorts between any of I2C, Vcc, and Gnd.

Dave

dastels
 
Posts: 10141
Joined: Tue Oct 20, 2015 3:22 pm

Re: NeoTrellis 8x8 Kit - Maybe DOA Neotrellis boards

by imnotjames on Sat May 21, 2022 8:39 pm

I cleaned off some of it but can't quite get all of it. I don't have solder wick (yet), so I did what I could.

Image

I tested with the multimeter between every edge pad (eg, between VIN and SDA, GND and SDA, etc). Only the pads I'd expect to have connections (GND to GND) had connections. Is that what you meant?

imnotjames
 
Posts: 4
Joined: Wed Jan 05, 2022 2:47 pm

Re: NeoTrellis 8x8 Kit - Maybe DOA Neotrellis boards

by dastels on Sun May 22, 2022 1:23 pm

That's exactly what I meant. It still doesn't work?

I'd be nice if they can be salvaged. Worst case, you should be able to tap into the DataIn of the first NeoPixel and have an 8x8 NeoPixel matrix.

Dave

dastels
 
Posts: 10141
Joined: Tue Oct 20, 2015 3:22 pm

Re: NeoTrellis 8x8 Kit - Maybe DOA Neotrellis boards

by imnotjames on Sun May 22, 2022 3:05 pm

Nope, still doesn't work. Like I'd said, I2C worked for OTHER boards when I was hooked into the BAD board. EG, I'd be hooked into 0x2E but couldn't see it listed - and still see 0x30 and 0x31.

I'm not super sure how to work with the neopixel matrices directly. Hardware isn't my forte (yet!) Like I said, I bought 2 new ones just off Adafruit's shop directly instead.

I'm in NYC all the time so I could drop them off if someone else might have better luck salvaging them. I'd really feel bad tossing them or something, they're so nice. :) The working 8x8 is gorgeous and so easy to work with in software.

imnotjames
 
Posts: 4
Joined: Wed Jan 05, 2022 2:47 pm

Re: NeoTrellis 8x8 Kit - Maybe DOA Neotrellis boards

by imnotjames on Fri May 27, 2022 6:42 pm

I used some desoldering wick to clean up one of them. Still the same as far as connections between pads.

Still no i2c but if I make connections to working boards the working boards show up even though I'm going through the i2c of the bad board.

Is it possible to get these replaced or refunded in some way? or does the fact that I've soldered them already prevent that?

imnotjames
 
Posts: 4
Joined: Wed Jan 05, 2022 2:47 pm

Re: NeoTrellis 8x8 Kit - Maybe DOA Neotrellis boards

by dastels on Fri May 27, 2022 6:47 pm

I2C is a parallel bus, so it doesn't go through anything... all SDA connections are connected together, etc.

Dave

dastels
 
Posts: 10141
Joined: Tue Oct 20, 2015 3:22 pm

Re: NeoTrellis 8x8 Kit - Maybe DOA Neotrellis boards

by dastels on Fri May 27, 2022 7:27 pm

As for replacement, it's pretty much impossible to tell if they were DOA, but let's assume they were. The work you did looked reasonably neat and shouldn't have caused problems. You seem to have learned and taken to heart the lesson to test boards before using them :) If nothing else it saves hassle and frustration having to undo/redo work.

Please email support@adafruit.com with a link to this thread, your order number, and request the replacement of 2 NeoTrellis 8x8 PCBs.

Dave

dastels
 
Posts: 10141
Joined: Tue Oct 20, 2015 3:22 pm

Please be positive and constructive with your questions and comments.