Matrix Orbital LK202-24-USB - Manual (Page 30)

6.4.1 Transaction command (254 C8 1 [flags] [Send Bits] [Recieve bits]
[Send data])
The transaction command will perform a single transaction on the 1-wire bus in this order;
1. Bus Reset.
2. Transmit data onto the bus.
3. Receive data from the bus.
Table 15: 1-Wire Transaction
Offset
(Bytes) Length
(Bytes) Name Description
0 1 Flags The flags byte controls the optional
components of the transaction.
1 1 Send Bits The number of bits that will be
transmitted onto the bus. The actual
bits to be transmitted are held in the
Send Data section.
2 1 Recieve Bits The number of bits to read off the
bus after the data to be put on the
bus has been sent.
3 Variable Send Data The data to be transmitted onto the
bus. The data is transmitted MSB
to LSB in the order that they are re-
ceived.
Table 16: 1-Wire Flags
Bit Description
7
6
Unused
5 (0 for future compatibility)
4
3
Add a CRC8 to the end of the transmitted data
2 (0 for future compatibility)
1 Assume last received byte is a CRC8 and validate it
0 Reset bus before transaction
The received data is sent back using the “Display return protocol”.
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