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M0A21/M0A23 Series
May 06, 2022
Page
237
of 746
Rev 1.02
M0
A21
/M
0
A
2
3
SE
RIES
TEC
H
NICAL
RE
FEREN
C
E
M
ANUAL
6.5
General Purpose I/O (GPIO)
6.5.1
Overview
This chip has up to 26 General Purpose I/O pins to be shared with other function pins depending on the
chip configuration. These 26 pins are arranged in 4 ports named as PA, PB, PC, PD. PA has 6 pins on
port, PB has 4 pins on port. PC and PD have 8 pins on port. Each 26 pins is independent and has the
corresponding register bits to control the pin mode function and data, except GPA[3]. GPA[3] is a input
pin.
The I/O type of each of I/O pins can be configured by software individually as Input, Push-pull output,
Open-drain output or Quasi-bidirectional mode. After the chip is reset, the I/O mode of all pins are
depending on CIOINI (CONFIG0[10]). Each I/O pin has a very weakly individual pull-up resistor which
is about 50 k
. Please refer to the M0A21/M0A23 Datasheet for detailed pin operation voltage
information about V
DD
electrical characteristics.
6.5.2
Features
Four I/O modes:
–
Quasi-bidirectional mode
–
Push-Pull Output mode
–
Open-Drain Output mode
–
Input only with high impendence mode
TTL/Schmitt trigger input selectable
I/O pin can be configured as interrupt source with edge/level setting
Configurable default I/O mode of all pins after reset by CIOINI (CONFIG0[10]) setting
–
CIOINI = 0, all GPIO pins in Quasi-bidirectional mode after chip reset
–
CIOINI = 1, all GPIO pins in input mode after chip reset
Supports independent pull-up control
Enabling the pin interrupt function will also enable the wake-up function