How to use SparkFun TCA9534 GPIO Expander with CircuitPython (CircuitPlayground Bluefruit for example)

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drmikegreen
 
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How to use SparkFun TCA9534 GPIO Expander with CircuitPython (CircuitPlayground Bluefruit for example)

Post by drmikegreen »

I need additional GPIO pins and happen to have several SparkFun TCA9534 boards and a variety of CircuitPython boards (Gemma M0, CircuitPlayground Bluefruit for example). What driver (if any) could I use?

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Franklin97355
 
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Re: How to use SparkFun TCA9534 GPIO Expander with CircuitPython (CircuitPlayground Bluefruit for example)

Post by Franklin97355 »

Sparkfun has python examples and packages that might help to give you a path. If you try and have problems you can ask specific questions here.

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drmikegreen
 
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Re: How to use SparkFun TCA9534 GPIO Expander with CircuitPython (CircuitPlayground Bluefruit for example)

Post by drmikegreen »

Alas, the SparkFun Python I2C package only supports the Raspberry Pi and only on a few hardware platforms. The TCA9523 is supposed to be a similar GPIO expander for which there is an Adafruit driver (Adafruit_AW9523). The default I2C address for this is 0x58. If I override this with "address=0x27", I get an I/O error when I try to create an instance of the GPIO expander using a CircuitPlayground Bluefruit board.

code.py output:
]0;🐍BLE:Off | code.py | 8.1.0-rc.0\Traceback (most recent call last):
File "code.py", line 7, in <module>
File "adafruit_aw9523.py", line 91, in __init__
File "adafruit_register/i2c_struct.py", line 81, in __get__
OSError: [Errno 5] Input/output error
]0;🐍BLE:Off | 81@adafruit_register/i2c_struct.py OSError | 8.1.0-rc.0\
Code done running.

import time
import busio
import board
import adafruit_aw9523

i2c = busio.I2C(board.SCL, board.SDA)
aw = adafruit_aw9523.AW9523(i2c,address=0x27)
print("Found AW9523")

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drmikegreen
 
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Re: How to use SparkFun TCA9534 GPIO Expander with CircuitPython (CircuitPlayground Bluefruit for example)

Post by drmikegreen »

I've found the Community driver library and there is a driver for the TCA9555 which is a "close relative" of the TCA9534 written by Gabriele Pongelli.

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drmikegreen
 
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Re: How to use SparkFun TCA9534 GPIO Expander with CircuitPython (CircuitPlayground Bluefruit for example)

Post by drmikegreen »

I'm giving up. I'm doing fine with "ready-made" CircuitPython library routines for a variety of devices. I just don't have the fluency either in Python or the internal structure and assumptions of the I/O library to do what I want without more "hand holding".

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Franklin97355
 
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Re: How to use SparkFun TCA9534 GPIO Expander with CircuitPython (CircuitPlayground Bluefruit for example)

Post by Franklin97355 »

You might try the Discord Adafruit Forum for the "help with Circuitpython" group

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adafruit2
 
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Re: How to use SparkFun TCA9534 GPIO Expander with CircuitPython (CircuitPlayground Bluefruit for example)

Post by adafruit2 »

its a totally different chip - your best bet is to ask Sparkfun to write a library for you since its their hardware (we dont own this chip)

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