MD-219 Hardware Manual
Display Control Interface
5-4
In the above screenshot, the scalar firmware version (1.0) is outlined in red.
UART Command Format
The message format is as follows:
Byte #
0
1
2,3,4
5
6
7 + (LEN-1)
7+LEN
ATTN
ADDR
CMD
LEN
IHCHK
DATA
IDCHK
The minimum message size is 7 bytes, and the maximum size is 82 bytes.
Command Format Details
ATTN (Attention)
This byte is used to identify the start of a message; it can be one of three values:
ATTN
Description
0x07
Command (ASCII BELL) packet
0x06
Acknowledge (ASCII ACK) packet
0x15
Negative ACK (ASCII NAK) packet
A device sends a command with the 0x07 Attention Code. The unit will respond to the command with either an
ACK if the command completed successfully, or a NAK if the command failed.
ADDR (Address)
This byte is used to specify the address where a command will be sent.
ADDR
Description
0xFF
Broadcast the command to all units
0x00 to 0x0F
Address of a specific unit, 0 to 15 (max 16 units)
