Rockwell Automation 5370 Color CVIM Communications Manual - Manual (Page 136)

Chapter 5
Using the RS–232 Ports
5–68
df1_bcc = –df1_bcc;
if (( (ch & 0xFF) == df1_bcc ) && !err )
{
_bios_serialcom(_COM_SEND,portnum–1,DLE);
_bios_serialcom(_COM_SEND,portnum–1,ACK);
good_string = 1;
}
else
{
_bios_serialcom(_COM_SEND,portnum–1,DLE);
_bios_serialcom(_COM_SEND,portnum–1,NAK);
if ( ––retry )
{
err = 0;
length = 0;
df1_bcc = 0;
msg = msg_start_ptr;
}
}
break;
case DLE:
if ( message_started )
{
if ( ++length > 128 )
{
_bios_serialcom(_COM_SEND,portnum–1,DLE);
_bios_serialcom(_COM_SEND,portnum–1,NAK);
message_started = 0;
err = 0;
length = 0;
df1_bcc = 0;
msg = msg_start_ptr;
}
else
{
*msg++ = ( ch & 0xFF );
df1_bcc += ( ch & 0xFF );
}
}
break;
default:
break;
}
}
else if ( message_started )
{
if ( ++length > 128 )