Intel 8253 - Page 582

XA User Guide 7-6 4/17/98
Figure 7.4 Typical XA External Bus Connections for 8-Bit Peripheral Devices
Figure 7.5 Typical XA External Bus Connections for 16-Bit Peripheral Devices
8-bit address latch
8-bit
peripheral
device
XA
A4 - A11
D0 - D7
A3 - A0,
(A12 - A19)
Address
decode
CS
A4D0-
A11D7
A3 - A0,
(A12 - A19)
ALE
RD
WR
LE
RD
WR
PSEN OE
for data
device
for code
device
16-bit address latch
XA
A4 - A19
Address
decode
CS
ALE
LE
for data
device
for code
device
(low byte)
A4D0-
A19D15
8-bit
Device
A3 - A1
WRH
WRL
RD
PSEN
D0 - D7
A3 - A1
WR
RD
OE
A4 - A19
CS
for data
device
for code
device
(high byte)
8-bit
Device
D8 - D15
A3 - A1
WR
RD
OE