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Many attempts to write to an i2c slave to make rgb leds light up have failed.

The hardware in question is found at: https://learn.adafruit.com/adafruit-neotrellis

There is an arduino library and a python library, but its hard to find out what i2c register does what.

My attempt, in python, is as follows:

i2c.writeto(0x2E, bytes([0x0E,0x01,0x01]), stop=True) # pin = 1 (as it is PORT A Pin 1 ??
i2c.writeto(0x2E, bytes([0x0E,0x02,0x00,0x00]), stop=True) # speed = 400khz  ?
i2c.writeto(0x2E, bytes([0x0E,0x03,0x06,0x06]), stop=True) # buff length?
i2c.writeto(0x2E, bytes([0x0E,0x04, 0x00, i, 0xff,0xff,0xff]), stop=True) # buff?
i2c.writeto(0x2E, bytes([0x0E,0x05,0x01]), stop=True) # show

The slave address is correct, and I get a response. I got my register constants from the following c-header file: https://adafruit.github.io/Adafruit_Seesaw/html/_adafruit__seesaw_8h.html

I got my info from the following document on page 30 / 38

https://cdn-learn.adafruit.com/downloads/pdf/adafruit-seesaw-atsamd09-breakout.pdf enter image description here

Here is the log of the commands from a logic analysor enter image description here

What can I do to get the leds to light up? I've used i2cdump without success, is there some brute force method to try out all combinations? What suggests do you have?

EDIT I realized that SPEED is supposed to be 8 bit not 16 bit but thats not really an issue.

Flying Swissman
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1 Answers1

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The following code fixed things, 

time.sleep(0.5)
i2c.writeto(0x2E, bytes([0x00,0x7f,0xff]), stop=True)       # ???

time.sleep(0.5)
i2c.writeto(0x2E, bytes([0x00,0x01]), stop=True)       # read id
result = bytearray(1)
time.sleep(0.5)
i2c.readfrom_into(0x2E, result)
print("module id=")
print(''.join('{:02x}'.format(x) for x in result))

i2c.writeto(0x2E, bytes([0x0E,0x02,0x01]), stop=True)  # speed = 200khz
time.sleep(0.5)
i2c.writeto(0x2E, bytes([0x0E,0x03,0x00,0x30]), stop=True)  # buff length
time.sleep(0.5)
i2c.writeto(0x2E, bytes([0x0E,0x01,0x03]), stop=True)       # pin = 3

i2c.writeto(0x2E, bytes([0x00,0x01]), stop=True)       # read id
result = bytearray(1)
i2c.readfrom_into(0x2E, result)
print("module id=")
print(''.join('{:02x}'.format(x) for x in result))


for i in range(16):
    print("writing led %d"%i)
    i2c.writeto(0x2E, bytes([0x0E,0x04, 0x00,i*3, 0x00,0xff,0x00]), stop=True)      # buff
    time.sleep(0.05)
    i2c.writeto(0x2E, bytes([0x0E,0x05]), stop=True)       # show 
    time.sleep(0.05)
Flying Swissman
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