Acces PCI-ICM422/2, Руководство пользователя

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PCI-ICM422/2(4) and 485/2(4) Manual
Page 5-4
Manual MPCI-ICM4S.F1b
The handler would first read the Interrupt Identification Register at Base A2. If the interrupt
is for Received Data Available, the handler then reads the data. If no interrupt is pending, control
exits the routine. A sample handler, written in C, is as follows:
readback = inportb(BA2);
if (readback & 4)
/*Readback will be set to 4 if data are available*/
data[i++]=inportb(BASEADDR);
outportb(0x20,0x20);
/*Write EOI to 8259 Interrupt Controller*/
return;
Transmission
RS485 transmission is simple to implement. The AUTO feature of the PCI-ICM422/485 card
automatically enables the transmitter when data are ready to send. No software enabling is required.
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++;
}