Issue Reading from I2C Register

[sageduggal]

Hello there,

I am attempting to write to a specific register, however when I check the register after writing, I am getting an odd output.

i2c.writeto_mem(i2caddress, PWR_MGMT_1, bytearray([0b00000000]))
print(i2c.readfrom_mem(i2caddress, PWR_MGMT_1, 1))
i2c.writeto_mem(i2caddress, PWR_MGMT_1, bytearray([0b00101000]))
print(i2c.readfrom_mem(i2caddress, PWR_MGMT_1, 1))

The first print output is correct:

b'\x00'

The second one, however, I do not understand:

b'('

Has anyone experienced this before? I must be doing something wrong but not sure what is going on. Thank you in advance.

[peterhinch]

The '(' character corresponds to 0x28 (try hex(ord(b'('))). Is this an unreasonable response?

[sageduggal]

Amazing, thank you! I was pulling my hair out trying to figure out what was happening. Thanks again.

[peterhinch]

The way that Python prints bytes and bytarray objects is a frequent cause of confusion. It's worth spending a bit of time getting really familiar with it so that this makes sense:

>>> bytearray((1,9,10,13,64))
bytearray(b'\x01\t\n\r@')