FTGPIO010 - Faraday Technology Corporation

FTGPIO010
GENERAL PURPOSE INPUT / OUTPUT
Version 1.4 | October 2006
Block Descriptions
APB Interface
The APB interface accepts standard APB bus signals. It services read / write requirements from the APB bus. When the
psel is active, the APB interface decodes the paddr to select one register. The pwrite signal indicates read or write
operation. If the pwrite signal indicates write, the pwdata will be written to the selected register. If the pwrite signal
indicates read, then the selected register will be read out to prdata.
Register Block
The register block includes data input / output registers, GPIO control registers, interrupt detection status registers,
interrupt control registers, bounce clock period register, bounce clock control registers, pull type registers and pull control
registers. The user can read or write these registers to control GPIO, interrupt detection, pull high / low, bouncing clock
and input / output data.
Input / Output
The pin directory controls the input / output MUXs. When a pin is programmed as an output pin, the output data are muxed
out to the gpio_out pin. When a pin is programmed as an input pin, the gpio_in pin is muxed into the input data register.
Interrupt Detection
The interrupt detection block handles the interrupt detection function. When the INTR option is defined, interrupt enable
is set and the pin is programmed as an interrupt input port, this block will be active.
Faraday’s GPIO supports rising edge, falling edge, rising and falling edges, and high / low level interrupt detection. Raw
status of the interrupt detection is put in the IntrRawState registers and masked status of the interrupt detection is put in
the IntrMaskedState registers. When the interrupt detection block senses an interrupt, gpio_intr will be triggered. The
programmer can judge the interrupt source through the gpio_mis [gn : 0] ports.
Bounce Clock
The bounce clock block provides a bouncing clock for each GPIO pin. When INTR option is defined and bounce enable is
set, this block will be active
If the pin is programmed as an interrupt input sense port, the pin can choose the bouncing clock as the clock source. The
bouncing clock is used to de-bounce the interrupt source. The default period of the bouncing clock is set to 0x7CF.
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