Pioneer PDP505CMX - HD Plasma Display, Справочник по командам

Страница: 16 / 22

16
RS-232C Adjustment Mode
7
Check Sum
The Check Sum is data to which 2-Byte ASCII code is added to a data group that is returned by a GET command.
STX
02 (hex) 2 Byte 3 Byte 03 (hex)
ID GET command ETX
STX
02 (hex)
GET command
3 Byte
Data
*Byte
Check sum
2 Byte
ETX
03 (hex)
PC side
Set side
.
Example) Check Sum value that is added when the GET command [GAA] returns the following 6-Byte data
GET command
GAA
Data (6 Byte)
100128
Data
100128
Check sum
0B
ETX
03 (hex)
Check sum
xx (before calculation)
Data group (ASCII)
+ check sum
47 41 41 31 30 30 31 32 38
when these values are added the result is 1F5 (hex)
as the data format, OB is converted to ASCII code and sent
The following data is output from the plasma display side.
xx, where xx is 0B (hex), is added to 1F5 so the last two digits are 00 (in this case 200)
≠
≠
≠
≠
STX
02 (hex)
GET command
GAA
The data group is put into binary code
one character at a time then displayed.
Only the last two digits are displayed.
7
Examples of check sum applications
Example 1) When the data is missing 1 Byte
47 41 31 30 30 32 38
check sum [OB (hex)] and the calculated [3C (hex)] do not match
Data
100 (missing data) 28
Check sum
0B
ETX
03 (hex)
STX
02 (hex)
GET command
GAA
data group is calculated according to rules set by a PC application
when these values are added, the result is 1C4 (hex)
≠
≠
≠
value xx, where xx is 3C (hex), is added to 1C4 such that the last
two digits are 00 (in this case 200)
Since they do not match, the PC application repeats the GET command
and retrieves the data again.
Example 2) When 1 Byte of data in the data is unreadable
47 41 31 30 33 30 32 38
check sum [OB (hex)] and the calculated [09 (hex)] do not match.
Data
100328
Check sum
0B
ETX
03 (hex)
STX
02 (hex)
GET command
GAA
data group is calculated according to rules by a PC application
when these values are added, the result is 1F7 (hex)
≠
≠
≠
value xx, where xx is 09 (hex), is added to 1F7 such that the last
two digits are 00 (in this case 200)
Since they do not match, the PC application repeats the GET command
and retrieves the data again.
* The returned data group is in capital English letters. Please keep this in mind when introducing it into
the binary code. .