System; Communication Control; Message Report - Planar VM55LX-X User Manual

System

6.

Communication Control

This defines the feedback command from the monitor to the host controller. When the device
receives a display command from the host controller the command reported to host controller
will be ACK, NAK or NAV.
Note: There is no reply message when the wrong ID address is used.
6.1

Message Report

Number of Field
Byte 1
Byte 2
Byte3
Byte4
Byte5
Byte6
Byte7
Byte8~Byte8+(N-1)
Byte 8+N
Example ACK Reply: (Display Address 01)
Header Monitor ID Category Page Length Control Data[0] Data[1]
0x21 0x01 0x00
Example NAK Reply: (Display Address 01)
Header Monitor ID Category Page Length Control Data[0] Data[1]
0x21 0x01 0x00
Example NAV Reply: (Display Address 01)
Header Monitor ID Category Page Length Control Data[0] Data[1] Checksum
0x21 0x01 0x00
VM Series Displays RS232 User Guide
020-1359-00A
Name of Field
Header Header = 0x21
Monitor ID
Monitor ID
Range: 1 ~ 255
Category 0x00
Page 0x00
Length of message plus Checksum code.
MsgLen Calculate the length from Control Byte to
Checksum Byte.
Control 0x01
Data[0] Copy the received Command code
Data[1]~Data[N] Returned data associated with command code
XOR of all byte in reply/report packet (except
Checksum
checksum itself)
0x00 0x04 0x01 0x00
0x00 0x04 0x01 0x00
0x00 0x04 0x01 0x00
Description
Checksum
0x00 0x25 Command is well executed.
Checksum
If the command code is
0x03 0x26 Data(0), the system will reply
"NAK."
Checksum error- "NAV".
0x04 0x21
Command Code Data(1)-"NAV".
Description
Description
Description
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