System Control Module

9.1.2GPIO Alternate Functions

Most GPIO pins have an alternate function that can be invoked to enable additional functionality within the SA-1100. If a GPIO is used for this alternate function, then it cannot be used as a GPIO at the same time. Pins 0 and 1 are reserved because of their special use during sleep mode and are not available for any alternate function. The following table shows each GPIO pin and its corresponding alternate function. For more details on an alternate function, see the section that corresponds to its name in the Unit column in the table.

Pin

Alternate Function

Direction

Unit

Signal Description

 

 

 

 

 

GP<27>

32KHZ_OUT

Output

Clocks

Raw 32.768-kHz oscillator output

 

 

 

 

 

GP<26>

RCLK_OUT

Output

Clocks

Internal clock/2

 

 

 

 

 

GP<25>

RTC clock

Output

RTC

Trimmed 1-Hz clock

 

 

 

 

 

GP<24>

Reserved

 

 

 

 

 

GP<23>

TREQB

Input

Test controller

TIC request B

 

 

 

 

 

GP<22>

TREQA/MBREQ

Input

Test controller

Either TIC request A or MBREQ

 

 

 

 

 

GP<21>

TIC_ACK/MBGNT

Output

Test controller

Either TIC acknowledge or

MBGNT

 

 

 

 

 

 

 

 

 

GP<21>

MCP_CLK

Input

Serial port 4

MCP clock in

 

 

 

 

 

GP<20>

UART_SCLK3

Input

Serial port 3:UART

Sample clock input

 

 

 

 

 

GP<19>

SSP_CLK

Input

Serial port 2:SSP

Sample clock input

 

 

 

 

 

GP<18>

UART_SCLK1

Input

Serial port 1:UART

Sample clock input

 

 

 

 

 

GP<17>

SDLC_AAF

Output

Serial port 1:SDLC

Abort after frame control

 

 

 

 

 

GP<16>

SDLC_SCLK

I/O

Serial port 1:SDLC

Geoport clock out

 

 

 

 

 

GP<15>

UART_RXD

Input

Serial port 1:UART

UART receive

 

 

 

 

 

GP<14>

UART_TXD

Output

Serial port 1:UART

UART transmit

 

 

 

 

 

GP<13>

SSP_SFRM

Output

Serial Port 4:SSP

SSP frame clock

 

 

 

 

 

GP<12>

SSP_SCLK

Output

Serial port 4:SSP

SSP serial clock

 

 

 

 

 

GP<11>

SSP_RXD

Input

Serial port 4:SSP

SSP receive

 

 

 

 

 

GP<10>

SSP_TXD

Output

Serial port 4:SSP

SSP transmit

 

 

 

 

 

GP<2..9>

LDD<8..15>

Output

LCD controller

High-order data pins for

split-screen color LCD support

 

 

 

 

 

 

 

 

 

GP<1>

Reserved

No alternate function

 

 

 

 

 

GP<0>

Reserved

—-

No alternate function

 

 

 

 

 

SA-1100 Developer’s Manual

9-9

Page 79
Image 79
Intel SA-1100 manual Gpio Alternate Functions, Pin Alternate Function Direction Unit Signal Description