Convert binary string to a binary integer in Python

Question

I want to send binary data via SPI, so I structured my code as constants of binary strings, representing various commands and registers on the SPI device.

RD = '01'
WR = '10'

MDR0 = '001'
MDR1 = '010'

so for example, if I want to write to MDR0 I add both strings and format them with a constant length:

msg = WR + MDR0
msg = int(msg, 2)

msg = [format(msg, '#010b')]
print(msg)
>> ['0b00010001']

My problem is, now msg has a str data not an int so it can't be sent using spidev package.

bin(int(msg[0],2))

The above code results in a string data type as well! How can I have this binary string as a binary integer where I might as well do binary operations on it?

Answer 1

Make integer bit masks. OR the bits to make IR register values:

import spidev

RD = 0b01 << 6  # bits 6-7
WR = 0b10 << 6

MDR0 = 0b001 << 3  # bits 3-5
MDR1 = 0b010 << 3

spi = spidev.SpiDev()
spi.open(bus, device)
msg = [WR | MDR0]
spi.xfer(msg)