63
Organization of banks
The I/O digital bank has a total of 24 I/O lines connected to a 26-pin header. The
lines are configured into three groups: ports A, B and C, each group consisting of 8
bits. Any of the lines at ports A, B or C can be configured individually as inputs or
outputs.
Figure 8–2
Organization of banks
Port addressing
Ports A, B, C and the control register are addressable. The base I/O address is
selectable in Setup as either 120h or 320h (120h default). Ports A, B, C and the
control register are addressable, with reference to the base address.
I/O lines pulled low
The I/O lines at ports A, B, and C are always pulled low. This allows a known state
upon powerup. 10K ohm resistor networks are used to configure the I/O lines as
low.
J6, Digital I/O
8
8
8
Port C
Port B
Port A
Control
Register
Base
120h* or
320h
Base + 2
122h* or
322h
Base + 1
121h* or
321h
Base + 3
123h* or
323h
* default
Summary of Contents for XE-900
Page 19: ...19 Figure 2 1 XE 900 SBC component diagram top ...
Page 20: ...20 Figure 2 2 XE 900 SBC component diagram bottom ...
Page 21: ...21 Figure 2 3 XE 900 SBC dimensions without Integrated Conductive Cooling System ...
Page 38: ...38 ...
Page 91: ...91 Figure 15 2 Dimensions for the Integrated Conductive Cooling System ...
