− 6 −
[1] Communications Format
The communication unit is a 4 (min)-24 (max) byte
packet.
・Communications Speed:
2400, 4800, 9600, 19200, 38400
9600 bps
(DEFAULT MD800 – 500)
* MD400 and MD300 cannot connect at 38400bps.
DEFAULT is 19200bps.
・
Data Length: 8 bit
・
Start Bit: 1 bit
・
Stop Bit: 1 bit
・
Parity: None
・
Flow Control: None
Packet Format
⁃
Header
Message
0
Message
1
Message
2
Checksum
Terminator
(0xFF)
Header Format
⁃
Bit 7
(MSB)
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 0
(LSB)
Bit 1
1 0/1 0/1 00000
・
Bit 0-2: Fixed [0]
*Reserved bit: Camera address
(0-7)
・
Bit 3: Fixed [0]
*Reserved bit: During broadcast
transmissions
・
Bit 4: Fixed [0]
・
Bit 5: During query commands [0], during settings
command [1]
・
Bit 6: During settings/query [0], during response to
query [1]
Terminator Format
⁃
Bit 7
(MSB)
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 0
(LSB)
Bit 1
111111 11
・
Bit 0-7: Fixed [1]
Message Format
⁃
Bit 7
(MSB)
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 0
(LSB)
Bit 1
0 0/1 0/1 0/1 0/1 0/1 0/10/1
・
Bit 0-6:Refer to the various commands (0-127)
・
Bit 7: Fixed [0]
Checksum Format
⁃
Bit 7
(MSB)
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 0
(LSB)
Bit 1
0 0/1 0/1 0/1 0/1 0/1 0/10/1
・
Bit 0-6: Take the value that sets the lower 7 bits of
the values added from the header to the
checksum to 0.
・
Bit 7: Fixed [0]
Response Command Format
⁃
Bit 7
(MSB)
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 0
(LSB)
Bit 1
11110/1 0/1 0/10/1
・
Bit 0-3: ACK(Ah) / NACK(Bh) / ERR(Ch)
・
Bit 4-7: Fixed [1]
・
ACK: This is the response when the process of the
received command is correctly completed after
receiving the data in the correct format.
・
NACK: This is the response when data is received in an
incorrect format.
・
ERR: Although the data is received in the correct format,
this is the response when the process regarding
the received command is incorrect or cannot be
conducted.
Communications Protocol