Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Developer’s Manual
Reference Number: 306262-004US
779
GPIO Controller—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
The clock generation logic is reset using an early reset, early_reset_n – this reset is de-
asserted prior to system reset being de-asserted. This ensures that GPIO15 provides a
clock out while system reset is still asserted.
15.4.3
APB Interface
The GPIO block interfaces to the Advanced Peripheral Bus, APB. The AHB/APB Bridge
provides the interface timing/signals required. Refer to the AMBA Rev 2.0 specification
for a detailed description on the Advanced Micro controller Bus Architecture. The GPIO
block responds to 8, 16, and 32 bit reads and writes.
15.5
Detailed Register Descriptions
The internal registers are accessed through the APB interface.
registers.
15.5.1
GPIO Output Register
Each pin’s output data is controlled by programming this register. Each of the 16 bits in
the register represents the data to be put on the output through a tri-state buffer,
depending upon the status of the GPOER. The register is read and written to through
the APB interface on the rising edge of apb_pclk.
Table 252.
Register Legend
Attribute
Legend
Attribute
Legend
RV
Reserved
RC
Read Clear
PR
Preserved
RO
Read Only
RS
Read/Set
WO
Write Only
RW
Read/Write
NA
Not Accessible
RW1C
Normal Read
Write ‘1’ to clear
RW1S
Normal Read
Write ‘1’ to set
Table 253.
Register Summary
Apb_paddr
[31:0]
Register Name
Description
Reset Value
Attribute
GPOUTR
GPIO pin data output register
RW
GPOER
GPIO pin out enable register
RW
GPINR
GPIO pin status register
RO
GPISR
GPIO interrupt status register
RW1C
GPIT1R
GPIO interrupt type register, inputs 7:0
RW
GPIT2R
GPIO pin interrupt type register, inputs
15:8
RW
GPCLKR
GPIO Clock Control Register
RW