While many BX boards have a connector on the motherboard, many do not. For those that do not, yet you still want to run a PCI card using these signals (for maximum compatibility), this information should prove useful.

In Intel i440BX motherboards without this connector, you need to solder some wires to the PIIX4E 82371EB southbridge chipset to get this working. There are two components in the 5-pin connector, Serial IRQ and PC/PCI for DMA.

The pinouts of the PC/PCI connector are as follows:

REQ# 1 2 GND
4 GNT#
GND 5 6 SERIRQ

On the PIIX4E 82371EB, the appropriate signals will be found as follows:

REQ#A - M01 GNT#A - N01
REQ#B - N02 GNT#B - P02
REQ#C - P03 GNT#C - P04

SERIRQ - J19

Please refer to the datasheet of the PIIX4E 82371EB for the locations of the pins on the underside of the motherboard.

It does not matter which pair of PC/PCI REQ and GNT signals you use, so long as both are As, Bs, or Cs.

See this post regarding these signals with the Yamaha YMF-7xx chips:

http://queststudios.com/smf/index.php/topic,3041.0.html

You should attach 8.2K resistors between the REQ and GNT lines and VCC3 and a 2.7K resistor between the SERIRQ and VCC3.