Protocol

Information about UART communication protocol

Information extracted from another Cubic sensor pdf. Reference: Laser Particle Sensor Module datasheet Model: PM2016 Version: V0.2, Date: June 25, 2021

UART Communication Protocol 1

1. General Statement

1. The data in this protocol is all hexadecimal data. For example,“46” for decimal [70].
2. [xx] is for single-byte data (unsigned, 0-255); for double data, high byte is in front of low byte.
3. Baud rate: 9600; Data Bits: 8; Stop Bits: 1; Parity: No
4. After power on the sensor, command shall be sent within 4 seconds.

2. Format of Serial Communication Protocol

Sending format to software:

Start	Symbol	Length	Command	Data 1	...	Data n.	Check Sum
HEAD	LEN	CMD	DATA1	....	...	DATAn	CS
11H	XXH	XXH	XXH	....	...	XXH	XXH

Detail description on protocol format:

Protocol Format	Description
Start symbol	Sending by software is fixed as [11H], module respond is fixed as [16H]
Length	Length of frame bytes= data length +1 (including CMD+DATA)
Command	Command
Data	Data of writing or reading, length is not fixed
Check sum	Cumulative sum of data = 256- (HEAD+LEN+CMD+DATA)

3. Command Table of Serial Protocol

Item No.	Function Description	Command
1	Read particle measurement result	0x0B
2	Open/close particle measurement	0x0C
3	Set up and read particle calibrated coefficient	0x07
4	Read software version number	0x1E
5	Read serial number	0x1F

4. Detail Description of UART Protocol

This part is my own interpretation of PM1003A sensor data from received messages in berry console at Tasmota. Note: The checksum last byte is a checksum type sum with 2-complement of all other bytes.

after sent 11 01 1E D0 many times I've got:

bytes('16110B000003E800000B05000003E80000006286')
bytes('16110B000003E800000B07000003E80000006284')
bytes('16110B000003E800000B09000003E80000006282')
bytes('16110B000003E800000B0B000003E80000006280')
bytes('16110B000003E800000B0D000003E8000000627E')
bytes('16110B000003E800000B0F000003E8000000627C')
bytes('16110B000003E800000B12000003E80000006279')
bytes('16110B000003E800000B15000003E80000006276')
bytes('16110B000003E800000B18000003E80000006273')
bytes('16110B000003E800000B1B000003E80000006270')
bytes('16110B000003E800000B1E000003E8000000626D')

from last message as example, we get:

16 11 0B	00 00 03 E8	00 00 0B 1E	00 00 03 E8	00 00 00 62	6D
HEADER: Start symbol num bytes cmd	DF1 DF2 DF3 DF4	DF5 DF6 DF7 DF8	DF9 DF10 DF11 DF12	DF13 DF14 DF15 DF16	Checksum

The information is the hexadecimal values 0x03 0xE8 which appears in other parts of the message for some unknown reason. The datasheet informs that bytes DF3 and DF4 are the PM 2.5 measurement, depicted as 256*DF3 + DF4