import fcntl import io import logging import pigpio import struct import time logger = logging.getLogger(__name__) actions = { "getnodeid": [0x90, 0xE0], "getserial": [0x90, 0xE1], "getdatatype": [0xA4, 0x00], "getdatalog": [0xA4, 0x01], "getsetting": [0xA4, 0x10], } class I2CRaw: def __init__(self, address, bus): I2C_SLAVE = 0x0703 self.fr = io.open(f"/dev/i2c-{bus}", "rb", buffering=0) self.fw = io.open(f"/dev/i2c-{bus}", "wb", buffering=0) fcntl.ioctl(self.fr, I2C_SLAVE, address) fcntl.ioctl(self.fw, I2C_SLAVE, address) def write_i2c_block_data(self, data): if type(data) is not list: return -1 data = bytearray(data) self.fw.write(data) return 0 def read_i2c_block_data(self, n_bytes): data_raw = self.fr.read(n_bytes) unpack_format = "B" * n_bytes return list(struct.unpack(unpack_format, data_raw)) def close(self): self.fr.close() self.fw.close() class I2CMaster: def __init__(self, address, bus, queue): self.i = I2CRaw(address=address, bus=bus) self.queue = queue def compose_request(self, action, identifier): if action == "getsetting": request = ( [0x80] + actions[action] + [0x04, 0x13] # read, length + [0x00, 0x00, 0x00, 0x00] # current + [0x00, 0x00, 0x00, 0x00] # min + [0x00, 0x00, 0x00, 0x00] # max + [0x00, 0x00, 0x00, 0x00] # step + [0x00, identifier, 0x00] ) else: # 0x80 = source, 0x04 = msg_type, 0x00 = length request = [0x80] + actions[action] + [0x04, 0x00] request.append(self.calculate_checksum(request)) return request def calculate_checksum(self, request): s = 0x82 for i in request: s += i checksum = 256 - (s % 256) if checksum == 256: checksum = 0 return checksum def execute_action(self, action, identifier): request = self.compose_request(action, identifier) request_in_hex = [hex(c) for c in request] logger.debug(f"Request: {request_in_hex}") result = None for i in range(0, 20): logger.debug(f"Executing action: {action}") self.i.write_i2c_block_data(request) time.sleep(0.21) logger.debug("Queue size: {}".format(self.queue.qsize())) if self.queue.qsize() > 0: result = self.queue.get() break if result is None: logger.error("No valid result in 20 requests") return result def close(self): self.i.close() class I2CSlave: def __init__(self, address, queue): self.address = address self.queue = queue self.pi = pigpio.pi() if not self.pi.connected: logger.error("not pi.connected") return def set_callback(self): logger.debug("set_callback()") self.event_callback = self.pi.event_callback(pigpio.EVENT_BSC, self.callback) self.pi.bsc_i2c(self.address) def callback(self, id, tick): logger.debug(f"callback({id}, {tick})") s, b, d = self.pi.bsc_i2c(self.address) result = None if b: logger.debug(f"Received {b} bytes! Status {s}") result = [hex(c) for c in d] logger.debug(f"Callback Response: {result}") if self.is_checksum_valid(result) and self.is_length_valid(result): self.queue.put(result) else: logger.debug(f"Received number of bytes was {b}") def is_checksum_valid(self, b): s = 0x80 for i in b[:-1]: s += int(i, 0) checksum = 256 - (s % 256) if checksum == 256: checksum = 0 if checksum != int(b[-1], 0): logger.debug(f"Checksum invalid (0x{checksum:02x} != {b[-1]})") return False return True def is_length_valid(self, b): length_in_msg = int(b[4], 0) actual_length = len(b) - 6 if length_in_msg != actual_length: logger.debug(f"Length invalid ({length_in_msg} != {actual_length})") return False return True def close(self): self.event_callback.cancel() self.pi.bsc_i2c(0) self.pi.stop()