pba_i2c.py

from machine import I2C
import logging as logging

###########################
# PBA I2C
###########################
#
# Command protocol:
#
# 0b1xxxxxxx: Get/set config data
# 0b10000001: Get module ID - Pico lights should return 0b00000010
# 0b10000010: Get version

class pba_i2c_hub:
    """
    Pico Boatman I2C hub device, polls I2C responder modules to control or
    return information as sensors.
    """
    def __init__(self, i2c: I2C) -> None:
        # Init logging
        self.log = logging.getLogger('pba_i2c')
        self.log.info("Init I2C Hub")
        self.i2c = i2c
        self.get_module_id_byte = 0b10000001
        self.get_version_byte = 0b10000010

    def send_data(self, data: list, address: int) -> None:
        """
        Send one byte of data over I2C, padding as needed to byte boundary.
        """
        # Pad data to protocol length
        while len(data) < 8:
            data.append(0)

        sendData = bytearray(data)
        self.i2c.writeto(address, sendData)

    def get_i2c_module_id(self, address: int) -> int:
        """
        Query I2C module for its one byte module ID and return, provide the i2c
        object to communicate via and the target address
        """
        command_byte = self.get_module_id_byte
        data = []
        data.append(command_byte)
        self.send_data(data, address)
        #Expect one byte status return
        returnData = self.i2c.readfrom(address, 1)
        returnData = int(returnData[0])
        return returnData
    
    def get_version(self, address: int) -> str:
        command_byte = self.get_version_byte
        data = []
        data.append(command_byte)
        self.send_data(data, address)        
        #Expect 1 byte length data return
        returnData = self.i2c.readfrom(address, 1)
        length = int.from_bytes(returnData, "big")
        #Expect immediate send of the version string, byte count specified above
        returnData = self.i2c.readfrom(address, length)
        returnData = returnData.decode('ansi')
        return returnData