SA1110 Datasheet, PDF (74/406 Pages) Intel Corporation – Intel StrongARM SA-1110 Microprocessor

System Control Module
9.1.1.2 GPIO Pin Direction Register (GPDR)
Pin direction is controlled by programming the GPIO pin direction register (GPDR). The GPDR
contains one direction control bit for each of the 28 port pins. If a direction bit is programmed to a
one, the port is an output. If it is programmed to a zero, it is an input. At hardware reset, all bits in
this register are cleared, configuring all GPIO pins as inputs. Soft resets and sleep reset have no
effect on this register. For reserved bits, writes are ignored and reads return zero. The following
table shows the location of each pin direction bit in the GPIO pin direction register.
.
0h 9004 0004
GPDR
Read/Write
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Reserved
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Bits
n
31..28
Name
PDn
—
Description
GPIO port pin direction n (where n = 0 through 27).
0 – Pin configured as an input.
1 – Pin configured as an output.
Reserved
9-4
SA-1110 Developer’s Manual