Pixel Bydgoszcz flip-dot display

pixel-poc.py

#!/usr/bin/env python3
import serial
import time
import struct
import sys

s = serial.Serial('/dev/serial0', 4800, parity='E') # parity is important here

device_id = '2' # usually can be chosen using selector on PCB
# preamble configured as per https://github.com/domints/PythonPixelBydgoszcz/blob/master/pixel2.py
preamble = '00 00 01 01 00 01 1A 00 00 00 30 22' 
payload = sys.argv[1]   # bitmap 1bit/pixel, starting in bottom-left and scanning up (MSB = bottom), hex-encoded string
message = preamble.replace(' ', '') + payload

def get_crc16(data: bytes):
    crc = 0x0000
    for i in range(0, len(data)):
        crc ^= data[i] << 8
        for j in range(0,8):
            if (crc & 0x8000) > 0:
                crc =(crc << 1) ^ 0x1021
            else:
                crc = crc << 1
    return struct.pack('<H', crc & 0xFFFF).hex().upper()

def initialize():
    send_raw('01SAT " 11"')
    send_raw(f"2{device_id}DPM 01FF57")

def send_packet(data):
    # first byte in the command specifies packet length
    data_len = struct.pack("B", len(data)//2+3).hex().upper() # +1 for length, +2 for CRC = +3
    data = data_len + data
    crc = get_crc16(bytes.fromhex(data))
    send_raw(f"2{device_id}DDB {data}{crc}")

def send_raw(data):
    print(data)
    # 0x01 - packet start; \r\n + 0x04 - packet ending
    s.write(bytes(f"\x01{data}\x0d\x0a\x04", 'ascii'))
    time.sleep(0.5)


initialize()
send_packet(message)