Редактирование: Mindset (раздел)

=== Step-By-Step Guide to Parsing a Packet ===
1. Keep reading bytes from the stream until a [SYNC] byte (0xAA) is encountered.

2. Read the next byte and ensure it is also a [SYNC] byte

• If not a [SYNC] byte, return to step 1.

• Otherwise, continue to step 3.

3. Read the next byte from the stream as the [PLENGTH].

• If [PLENGTH] is 170 ([SYNC]), then repeat step 3.

• If [PLENGTH] is greater than 170, then return to step 1 (PLENGTH TOO LARGE).

• Otherwise, continue to step 4.

4. Read the next [PLENGTH] bytes of the [PAYLOAD…] from the stream, saving them into a storage

area (such as an unsigned char payload[256] array). Sum up each byte as it is read by

incrementing a checksum accumulator (checksum += byte).

5. Take the lowest 8 bits of the checksum accumulator and invert them. Here is the C code:

checksum &= 0xFF;

checksum = ~checksum & 0xFF;

6. Read the next byte from the stream as the[CHKSUM] byte.

• If the [CHKSUM] does not match your calculated chksum (CHKSUM FAILED).

• Otherwise, you may now parse the contents of the Payload into DataRows to obtain the

Data Values, as described below.

• In either case, return to step 1.