Intel PXA26X User Manual
Intel® PXA26x Processor Family Developer’s Manual
4-3
System Integration Unit
4.1.2
GPIO Alternate Functions
GPIO pins are capable of having as many as six alternate functions (shown
) that can be
set to enable additional functionality within the processor. If a GPIO is used for an alternate
function, then it cannot be used as a GPIO at the same time. GPIO[0] is reserved because of its
special use during sleep mode and is not available for alternate functions. GPIO[15:0] are used for
sleep-mode wake up. The wake-up functionality is described in
function, then it cannot be used as a GPIO at the same time. GPIO[0] is reserved because of its
special use during sleep mode and is not available for alternate functions. GPIO[15:0] are used for
sleep-mode wake up. The wake-up functionality is described in
shows each GPIO pin and its corresponding alternate functions.
For more information on alternate functions, refer to the source unit column in
for the
appropriate section of this document.
Table 4-1. GPIO Alternate Functions (Sheet 1 of 5)
Pin
Alternate
Function Name
Function Name
Alternate Function
Assignment
Assignment
AF{n}
encoding
encoding
Source Unit
Signal Description and comments
GP1
GP_RST
ALT_FN_1_IN
01
Clocks & Power
Manager Unit
Manager Unit
Active low GP_reset
GP6
MMCCLK
ALT_FN_1_OUT
01
Multimedia Card
(MMC) Controller
(MMC) Controller
MMC Clock
GP7
48 MHz clock
†
ALT_FN_1_OUT
01
Clocks & Power
Manager Unit
Manager Unit
48-MHz clock output
GP8
MMCCS0
ALT_FN_1_OUT
01
Multimedia Card
(MMC) Controller
(MMC) Controller
MMC Chip Select 0
GP9
MMCCS1
ALT_FN_1_OUT
01
MMC Chip Select 1
USB_RCV
ALT_FN_1_IN
01
Single Ended USB
USB Device Controller RCV
GP10
RTCCLK
ALT_FN_1_OUT
01
System Integation
Unit
Unit
real time clock (1 Hz)
GP11
3.6 MHz
ALT_FN_1_OUT
01
Clocks & Power
Manager Unit
Manager Unit
3.6-MHz oscillator out
GP12
32 KHz
ALT_FN_1_OUT
01
32-KHz out
GP13
MBGNT
ALT_FN_2_OUT
10
Memory Controller
memory controller grant
GP14
MBREQ
ALT_FN_1_IN
01
memory controller alternate bus
master request
master request
GP15
nCS_1
ALT_FN_2_OUT
10
Memory Controller
Active low chip select 1
GP16
PWM0
ALT_FN_2_OUT
10
System Integration
PWM0 output
GP17
PWM1
ALT_FN_2_OUT
10
PWM1 output
GP18
RDY
ALT_FN_1_IN
01
Memory Controller
Ext. Bus Ready
GP19
DREQ[1]
ALT_FN_1_IN
01
Memory Controller
External DMA Request
GP20
DREQ[0]
ALT_FN_1_IN
01
External DMA Request
GP23
SCLK
ALT_FN_2_OUT
10
SSP Serial Port
SSP clock
GP24
SFRM
ALT_FN_2_OUT
10
SSP Frame
GP25
TXD
ALT_FN_2_OUT
10
SSP transmit
GP26
RXD
ALT_FN_1_IN
01
SSP receive
GP27
EXTCLK
ALT_FN_1_IN
01
SSP ext_clk