SA1110 Datasheet, PDF (79/406 Pages) Intel Corporation – Intel StrongARM SA-1110 Microprocessor

System Control Module
9.1.2
GPIO Alternate Functions
Most GPIO pins have an alternate function that can be invoked to enable additional functionality
within the SA-1110. 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
GP 27
GP 26
GP 25
GP 24
GP 23
GP 22
GP 21
GP 21
GP 20
GP 19
GP 18
GP 17
GP 16
GP 15
GP 14
GP 13
GP 12
GP 11
GP 10
GP 2..9
GP 1
GP 0
Alternate Function Direction
32KHZ_OUT
RCLK_OUT^†
RTC clock
Reserved
TREQB^†
TREQA^†/MBREQ
Output
Output
Output
—
Input
Input
TIC_ACK^†/MBGNT Output
MCP_CLK
UART_SCLK3
SSP_CLK
UART_SCLK1
Reserved
GPCLK_OUT
UART_RXD
UART_TXD
SSP_SFRM
SSP_SCLK
SSP_RXD
SSP_TXD
Input
Input
Input
Input
—
Output
Input
Output
Output
Output
Input
Output
LDD 8..15
Output
Reserved
—
Reserved
—-
Unit
Signal Description
Clocks
Clocks
RTC
—
Test controller
Test controller
Test controller
Serial port 4
Serial port 3:UART
Serial port 2:SSP
Serial port 1:UART
—
Serial port 1
Serial port 1:UART
Serial port 1:UART
Serial Port 4:SSP
Serial port 4:SSP
Serial port 4:SSP
Serial port 4:SSP
LCD controller
—
—
Raw 32.768-kHz oscillator output
Internal clock/2
Real time clock
—
TIC request B
Either TIC request A or MBREQ
Either TIC acknowledge or
MBGNT
MCP clock in
Sample clock input
Sample clock input
Sample clock input
—
General-purpose clock out
UART receive
UART transmit
SSP frame clock
SSP serial clock
SSP receive
SSP transmit
High-order data pins for
split-screen color LCD support
No alternate function
No alternate function
† To enable RCLK_OUT, it is also necessary to set bits 31:29 of the Test Unit Control Register (TUCR) =
0b100. See Appendix D, “Internal Test” for more information about the TUCR.
† The signals, TREQA, TREQB, and TIC_ACK are reserved by Intel for test purposes.
SA-1110 Developer’s Manual
9-9