VT82C686B
XD Interface
Signal Name
Pin #
I/O Signal Description
/ PCS0# / GPO12
T5
O
(Rx76[1]=0) Asserted low for all I/O read cycles and for
X-Bus Data Direction.
XDIR
memory read cycles to the programmed BIOS address space. XDIR is tied
directly to the direction control of a 74F245 transceiver that buffers the X-Bus
data and ISA-Bus data. The transceiver output enable may be grounded. SD0-7
connect to the “A” side of the transceiver and XD0-7 connect to the “B” side.
XDIR high indicates that SD0-7 drives XD0-7.
Serial IRQ
Signal Name
Pin #
I/O Signal Description
/ DRQ2
/ GPO24
/ FDCDRQ / USBOC1#
H3
I
(Rx68[3] = 1, Rx74[6] = 0 and Rx75[3] = 1)
(Rx68[3] = 1 and Rx74[6] = 1)
SERIRQ
Serial IRQ
/ DACK5#
L4
I
SERIRQ
Serial IRQ
/ GPO19 / MC97IRQ
Revision 1.71 June 9, 2000
-20-
Pinouts
ETC [ ETC ]
