Title: Dflex Enabling UART Interrupts to ISA Bus
Keywords: Interrupts Out2 Dflex
Date: November 29 1996
KDB: KDB-047
Revision: 0.00
Author: AES
Distribution: External
This KDB only applies to customers who are developing their own serial driver for the Dflex. Any standard serial driver will do this already. The following describes how to enable the generation of interrupts on a typical dumb serial board (including our Dflex products).
Typically a 16450 or 16550 type UART will power up with its ability to generate interrupts disabled. To enable a port’s interrupts at the chip level the OUT2 pin must be raised.
The suggested 8086 assembly language to do this is as follows:
mov dx,UARTbase+4
in al,dx
or al,08h
out dx,al
For more information on the use of interrupts and UARTS consult the: National Semiconductor – Data Communications Local Area Networks UARTs Handbook
End of KDB-047