import Adafruit_PureIO.smbus as smbus import time class I2C: MASTER = 0 SLAVE = 1 _baudrate = None _mode = None _i2c_bus = None def __init__(self, bus_num, mode=MASTER, baudrate=None): if mode != self.MASTER: raise NotImplementedError("Only I2C Master supported!") _mode = self.MASTER #if baudrate != None: # print("I2C frequency is not settable in python, ignoring!") try: self._i2c_bus = smbus.SMBus(bus_num) except FileNotFoundError: raise RuntimeError("I2C Bus #%d not found, check if enabled in config!" % bus_num) def scan(self): """Try to read a byte from each address, if you get an OSError it means the device isnt there""" found = [] for addr in range(0,0x80): try: self._i2c_bus.read_byte(addr) except OSError: continue found.append(addr) return found def writeto(self, address, buffer, *, start=0, end=None, stop=True): if end is None: end = len(buffer) self._i2c_bus.write_bytes(address, buffer[start:end]) def readfrom_into(self, address, buffer, *, start=0, end=None, stop=True): if end is None: end = len(buffer) readin = self._i2c_bus.read_bytes(address, end-start) for i in range(end-start): buffer[i+start] = readin[i] def writeto_then_readfrom(self, address, buffer_out, buffer_in, *, out_start=0, out_end=None, in_start=0, in_end=None, stop=False): if out_end is None: out_end = len(buffer_out) if in_end is None: in_end = len(buffer_in) if stop: # To generate a stop in linux, do in two transactions self.writeto(address, buffer_out, start=out_start, end=out_end, stop=True) self.readfrom_into(address, buffer_in, start=in_start, end=in_end) else: # To generate without a stop, do in one block transaction if out_end-out_start != 1: raise NotImplementedError("Currently can only write a single byte in writeto_then_readfrom") readin = self._i2c_bus.read_i2c_block_data(address, buffer_out[out_start:out_end][0], in_end-in_start) for i in range(in_end-in_start): buffer_in[i+in_start] = readin[i]