Marine PC MPC-ML2DVR, Руководство пользователя, Страница: 48 / 64

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MPC-ML2DVR-UM(A) 3/2015
CoMMunICAtIon ProtoCoL (ContInueD)
Checksum Calculation
unsigned char ComputeChecksum(string text)
{
unsigned char startInx, endInx, result;
startInx = Pos(‘$’, text) + 1; //start at character after ‘$’ in string
endInx = Pos(‘*’, text) - 1; //end at character before ‘*’ in string
result = 0;
for(int n = startInx; n < = endInx; n++)
{
result = result ^ text[n];
}
return result;
}
Commands
The following table references the commands the DVR supports (Table 13). (Table continues
on the next page.)
CoMManD DiReCtion ReSPonSe DeSCRiPtion
DSKDn from DVr n/A Key pressed
DSKuP from DVr n/A Key released (from press)
DSCDV to DVr DSACK/DSnAK Change Display Video
DSIBt to DVr DSBtr/DSnAK Initiates IBIt System test (PSM)
DSBtQ to DVr DSBtr/DSnAK requests last IBIt System test results
DSBtr from DVr n/A IBIt System test response
DSfwQ to DVr DSfwr/DSnAK request firmware Version
DSfwr from DVr n/A firmware Version response
DSPKM to DVr DSACK/DSnAK Program Key Mode
DSPKD to DVr DSACK/DSnAK Program Key Down text Msg
DSPKu to DVr DSACK/DSnAK Program Key up text Msg
table 13