Ublox NINA-B1 Series, Руководство по системной интеграции

Страница: 56 / 63

NINA-B1 series - System integration manual
UBX-15026175 - R16 Appendix Page 56 of 63
C1-Public
C XMODEM code example
Example that shows a basic XMODEM implementation and a CRC calculation in C#.
private const int XMODEM_ACK = 6;
private const int XMODEM_NAK = 21;
private const int XMODEM_EOT = 4;
public Boolean XModemSend ( Stream inputStream )
{
byte blockCnt = 0;
Boolean result = false ;
BufferedStream bufferedInput = new BufferedStream ( inputStream );
byte [] block = new Byte [133];
int bytesRead ;
do {
for ( int i = 0; i < 133; i ++) {
block [ i ] = 0;
}
bytesRead = bufferedInput . Read ( block , 3, 128);
blockCnt ++;
block [0] = 1;
block [1] = blockCnt ;
block [2] = ( byte )(255 - blockCnt );
ushort crc = xmodemCalcrc ( block , 3, 128);
block [131] = ( Byte )(( crc >> 8) & 0xFF);
block [132] = ( Byte )( crc & 0xFF);
try {
this . Write ( block , 0, block . Length );
} catch ( Exception ) {
result = false ;
break ;
}
try {
Byte res = ( Byte ) this . ReadByte ();
while ( res == 'C' ) {
res = ( Byte ) this . ReadByte ();
}
if ( res == XMODEM_ACK ) {
DebugPrint ( “Bytes sent {0}”, bytesRead ));
if ( bytesRead < 128) {
byte [] eot = new byte [1];
eot [0] = XMODEM_EOT ;
this . Write ( eot , 0, 1);
res = ( Byte ) this . ReadByte ();
if ( res == XMODEM_ACK ) {
/* File sent ok */
result = true ;
} else {
result = false ;
}
}
} else {
// No ACK received, stop transmission no retransmission implemented
result = false ;
break ;
}
} catch ( TimeoutException ) {
result = false ;
break ;
}
}
while ( bytesRead == 128);
DebugPrint ( “Bytes sent {0}”, bytesRead ));
bufferedInput . Close ();