Si1000/1/2/3/4/5
Table 21.1. Port I/O Assignment for Analog Functions
Analog Function
Potentially
Assignable Port Pins
SFR(s) used for
Assignment
ADC Input
P0.0–P2.6
P0.0–P2.6
P0.0–P2.6
P0.0
ADC0MX, PnSKIP
CPT0MX, PnSKIP
CPT1MX, PnSKIP
REF0CN, PnSKIP
REF0CN, PnSKIP
IREF0CN, PnSKIP
OSCXCN, PnSKIP
OSCXCN, PnSKIP
Comparator0 Input
Comparator1 Input
Voltage Reference (VREF0)
Analog Ground Reference (AGND)
Current Reference (IREF0)
External Oscillator Input (XTAL1)
External Oscillator Output (XTAL2)
P0.1
P0.7
P0.2
P0.3
21.2.2. Assigning Port I/O Pins to Digital Functions
Any Port pins not assigned to analog functions may be assigned to digital functions or used as GPIO. Most
digital functions rely on the Crossbar for pin assignment; however, some digital functions bypass the
Crossbar in a manner similar to the analog functions listed above. Port pins used by these digital func-
tions and any Port pins selected for use as GPIO should have their corresponding bit in PnSKIP set
to 1. Table 21.2 shows all available digital functions and the potential mapping of Port I/O to each digital
function.
Table 21.2. Port I/O Assignment for Digital Functions
Digital Function
Potentially Assignable Port Pins
SFR(s) used for
Assignment
UART0, SPI1, SPI0, SMBus,
CP0 and CP1 Outputs, Sys-
tem Clock Output, PCA0,
Timer0 and Timer1 External
Inputs.
Any Port pin available for assignment by the
Crossbar. This includes P0.0–P2.6 pins which
have their PnSKIP bit set to 0.
Note: The Crossbar will always assign UART0
and SPI1 pins to fixed locations.
XBR0, XBR1, XBR2
Any pin used for GPIO
P0.0–P2.6
P0SKIP, P1SKIP,
P2SKIP
21.2.3. Assigning Port I/O Pins to External Digital Event Capture Functions
External digital event capture functions can be used to trigger an interrupt or wake the device from a low
power mode when a transition occurs on a digital I/O pin. The digital event capture functions do not require
dedicated pins and will function on both GPIO pins (PnSKIP = 1) and pins in use by the Crossbar (PnSKIP
= 0). External digital even capture functions cannot be used on pins configured for analog I/O. Table 21.3
shows all available external digital event capture functions.
210
Rev. 1.0
SILICON [ SILICON ]
