added README and debug.py

Author: rokiden

README.md

@@ -1,3 +1,6 @@
+# Tuya CO2 Sensor firmware located at 'user' directory
+Original library README below.
+
 # About
 
 FwLib_STC8 is a lite firmware library for STC8G/STC8H series MCU.

user/README.md

@@ -0,0 +1,3 @@
+https://developer.tuya.com/en/docs/iot/zt3l-module-datasheet?id=Ka438n1j8nuvu
+https://developer.tuya.com/en/docs/iot/tuya-zigbee-module-uart-communication-protocol?id=K9ear5khsqoty#dataFormat
+https://www.tinytronics.nl/index.php?route=product/product/get_file&file=4660/MTP40-F-CO2-sensor-module-single-channel.pdf

user/debug.py

@@ -0,0 +1,153 @@
+import serial
+import time
+
+log = bytearray()
+
+
+def get_bytes(n):
+    d = ser.read(n)
+    log.extend(d)
+    # print(d.hex())
+    return d
+
+
+def log_flush():
+    print(len(log), log.hex())
+    log.clear()
+
+
+def get_byte():
+    return get_bytes(1)[0]
+
+
+def get_int(n):
+    return int.from_bytes(get_bytes(n))
+
+
+prev_time = None
+
+
+def get_time():
+    global prev_time
+    t = time.time()
+    if prev_time is None:
+        d = 0
+    else:
+        d = t - prev_time
+    prev_time = t
+    return f'[{d:.03f}]'
+
+
+class Tuya:
+    CMDS = {
+        0x1: 'QPI',
+        0x2: 'RNS',
+        0x3: 'CZM',
+        0x6: 'RSP',
+        0x20: 'QZS'
+    }
+
+    @staticmethod
+    def wait_start():
+        b = None
+        i = 0
+        while True:
+            bp = b
+            b = get_byte()
+            i += 1
+            if (bp, b) == (0x55, 0xaa):
+                skipped = i - 2
+                if skipped:
+                    print('skipped', skipped)
+                return
+
+    @staticmethod
+    def main():
+        while True:
+            Tuya.wait_start()
+            ver = get_byte()
+            assert ver == 2
+            seq = get_int(2)
+            cmd = get_byte()
+            len = get_int(2)
+            data = get_bytes(len)
+
+            csum = sum(log) % 256
+
+            check = get_byte()
+
+            cmd_name = Tuya.CMDS.get(cmd, '')
+            if cmd == 0x6 and len == 8:
+                parsed = f'CO2:{int.from_bytes(data[-4:])}'
+            elif cmd == 0x1 and len == 28:
+                parsed = data.decode()
+            elif cmd == 0x2 and len == 1:
+                parsed = {0: 'not paired', 1: 'paired', 2: 'exc', 3: 'pairing'}[data[0]]
+            else:
+                parsed = ''
+            log_flush()
+            print(f'{seq:04X} {cmd:02X}:{cmd_name} {len:3d}[{data.hex()}] {parsed} {csum == check}')
+
+
+class Sensor:
+    @staticmethod
+    def wait_start():
+        b = None
+        i = 0
+        while True:
+            bp = b
+            b = get_byte()
+            i += 1
+            if (bp, b) == (0x42, 0x4d):
+                skipped = i - 2
+                if skipped:
+                    print('skipped', skipped)
+                return
+
+    @staticmethod
+    def main():
+        while True:
+            Sensor.wait_start()
+            inst = get_byte()
+            assert inst == 0xA0
+            cmd = get_int(2)
+            len = get_int(2)
+            data = get_bytes(len)
+            csum = sum(log)
+            check = get_int(2)
+            cmd_name = Sensor.CMDS.get(cmd, '')
+            if cmd == 0x3 and len == 5:
+                parsed = f'CO2:{int.from_bytes(data[:-1])} V:{data[-1]}'
+            else:
+                parsed = ''
+            log_flush()
+            print(f'{get_time()} {cmd:02X}:{cmd_name} {len:3d}[{data.hex()}] {parsed} {csum == check}')
+
+
+class Trim:
+    @staticmethod
+    def main():
+        tp = None
+        ts = None
+        avg_sum = 0
+        avg_num = 0
+        while True:
+            b = get_byte()
+            t = time.time_ns()
+            if ts is None:
+                ts = t
+            if tp is not None:
+                d = t - tp
+                avg_sum += d
+                avg_num += 1
+                avg = avg_sum / avg_num
+                avg2 = (t - ts) / avg_num
+                print(d, avg, avg2, avg_num, b)
+            tp = t
+
+
+if __name__ == '__main__':
+    ser = serial.Serial('/dev/ttyUSB1', baudrate=9600)
+
+    Sensor.main()
+    # Tuya.main()