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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—GPIO Controller
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Developer’s Manual
August 2006
776
Reference Number: 306262-004US
15.0
GPIO Controller
15.1
Overview
The purpose of this document is to outline the functional requirements of the General-
Purpose Input/Output (GPIO) pins for the Intel
®
IXP45X and Intel
®
IXP46X Product
Line of Network Processors.
The IXP45X/IXP46X network processors provide 16 general-purpose input/output pins
for use in generating and capturing application specific input and output signals. Each
pin can be programmed as either an input or output, and when GPIO0 through GPIO12
are programmed as an input, they can be used as an interrupt source. In addition, two
of the pins can be programmed to provide a user programmable frequency source.
During a reset all pins are configured as inputs and remain in this state until configured
otherwise, with the exception of GPIO15, which by default will provide a clock output.
Each GPIO pin is capable of driving external LEDs. There are eight distinct register
functions used in the GPIO module. When used as an interrupt source, each pin can
detect interrupts as active high, active low, rising edge, falling edge, or transitional.
Note:
In this document, the NPE (Network Processing Engine) microprocessor core is also
referred to as PSM or PSM2. The preferred term is NPE core.
Another two signals are going to the Tsync unit through the GPIO Controller, these two
are snapshot signals for the Tsync unit. They are wired through the GPIO, and goes to
sync cells in the tsync unit. The Auxiliary slave snapshot signal is connected to
GPIO_IN[8] and the Auxiliary master snapshot signal is connected to GPIO_IN[7].
15.2
Feature List
• Sixteen GPIO pins.
• Thirteen pins capable of being an interrupt source.
• Each pin can be programmed to be an input or output.
• Two pins can be programmed as a programmable clock source.
• Eight different functional registers.
• AMBA APB interface.
• NPE core and IEEE1588 debug functionality.
• Two snapshot trigger inputs.
• GPIO_IN[7:0] can be individually routed directly to the NPEs.
15.3
Block Diagram
A block diagram of the General-Purpose I/O block is shown in