PXN20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor 3-1
Chapter 3
Signal Description
3.1 Introduction
This chapter describes signals that connect off-chip. It includes a signal properties summary, power and
ground segmentation summary, package pinouts, and detailed descriptions of signals. Because the PXN20
comes in multiple packages, some signals may not be available on every package. Refer to the PXN20
Microcontroller Data Sheet for electrical characteristics.
3.2 Signal Properties Summary
Table 3-1 shows the signals properties for each pin on PXN20. For all port pins that have an associated
SIU_PCRn register to control pin properties, the supported functions column lists the functions associated
with the programming of the SIU_PCRn[PA] bit in the order: general-purpose input/output (GPIO),
function 1, function 2, and function 3 (see Figure 3-1). When an alternate function is not implemented for
a value of SIU_PCRn[PA], a dash is shown in the Description column and the respective value in the PA
bitfield is reserved.
Figure 3-1. Supported Functions Example
PA[ 0]
AN[0]
GPIO
Function 1
Functions 2 and 3
not implemented
000
01
10
11
Supported
Functions
2
GPIO
(PCR)
Num
3
PA
4
Description
Port A GPI
ADC Analog Input
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