Manual Number: 00650-148-1
Page 18
PCI-ICOM485/4 Manual
Transmission
RS-485 transmission is simple to implement. To transmit a string of data, the transmitter must first
check Bit 5 of the Line Status Register at Base A5. That bit is the
transmitter-holding-register-empty flag. If it is high, the transmitter has sent the data. The process
of checking the bit until it goes high, followed by a write, is repeated until no data remains.
The following C code fragment demonstrates this process:
while(data[i]);
/*While there is data to send*/
{
while(!(inportb(BA5)&0x20)); /*Wait until
transmitter is empty*/
outportb(BASEADDR,data[i]);
i++;
}
Summary of Contents for PCI-ICOM485/4
Page 1: ...Model PCI ICOM485 4 PCI ICOM485 2 Product Manual MANUAL NUMBER 00650 148 1C...
Page 3: ...Page iv This page intentionally left blank...
Page 7: ...Page viii This page intentionally left blank...
Page 14: ...ManualNumber 00650 148 1 Page 6 PCI ICOM485 4 Manual This page intentionally left blank...
Page 19: ...ManualNumber 00650 148 1 Page 11 PCI ICOM485 4 2 OPTION SELECTION MAP...
Page 20: ...ManualNumber 00650 148 1 Page 12 PCI ICOM485 4 Manual This page intentionally left blank...
Page 22: ...ManualNumber 00650 148 1 Page 14 PCI ICOM485 4 Manual This page intentionally left blank...
Page 28: ...ManualNumber 00650 148 1 Page 20 PCI ICOM485 4 Manual This page intentionally left blank...
Page 30: ...ManualNumber 00650 148 1 Page 22 PCI ICOM485 4 Manual This page intentionally left blank...