INIT_SEQ = {

"CRSF": [0xEC,0x04,0x32,ord('b'),ord('l')],

"GHST": [0x89,0x04,0x32,ord('b'),ord('l')],

}

BIND_SEQ = {

"CRSF": [0xEC,0x04,0x32,ord('b'),ord('d')],

"GHST": [0x89,0x04,0x32,ord('b'),ord('d')],

}

MODEL_SEQ = [0xEC,0x04,0x32,ord('m'),ord('m')]

def calc_crc8(payload, poly=0xD5):

crc = 0

for data in payload:

crc ^= data

for _ in range(8):

if crc & 0x80:

crc = (crc << 1) ^ poly

else:

crc = crc << 1

return crc & 0xFF

def get_telemetry_seq(seq, key=None):

payload = list(seq)

if payload:

if key:

if type(key) == str:

key = [ord(x) for x in key]

payload += key

payload[1] += len(key)

payload += [calc_crc8(payload[2:])]

return bytes(payload)

def get_init_seq(module, key=None):

return get_telemetry_seq(INIT_SEQ.get(module, []), key)

def get_bind_seq(module, key=None):

return get_telemetry_seq(BIND_SEQ.get(module, []), key)

def get_model_seq(model):

return get_telemetry_seq(MODEL_SEQ, model)

if __name__ == '__main__':

print("CRC: %s" % get_init_seq('CRSF', [ord(x) for x in 'R9MM']))

print("CRC: %s" % get_init_seq('CRSF', 'R9MM'))