GPIO — General purpose input/output

By default, the general purpose input/output pins, GPIO[n], are set as input with weak pull-down. GPIO is supplied by the VDDIO pin.

The number of GPIOs varies with product variant and package. See Pin assignments for more information about the number of supported GPIOs.

GPIO has the following configurable features:

General purpose input
Control input
Output
BUCK control
LOADSW control

Note: Events may occur when GPIO configuration is changed on the fly.

Pull-down is prioritized if both pull-up and pull-down are activated on a GPIO pin at the same time.

The following figure shows BUCK control.

Figure 1. GPIO concept

Pins LED0, LED1, and LED2 can be used as open-drain outputs, see LEDDRV — LED drivers.

Pin configuration

The GPIO peripheral implements up to 5 pins, GPIO[0...4]. Each of these pins can be individually configured in the GPIOMODE[n] registers.

General purpose input

GPIO can be used as a general purpose input to monitor the input logic level. Debounce is set in register GPIO.DEBOUNCE[n]. Set GPI.INPUT to use GPIO[n] without setting an event.

It can also be used as an input to trigger an event. Set bit GPI.RISING.EVENT to generate an event on the rising edge. To generate an event on a falling edge, set bit GPI.FALLING.EVENT. The events are visible in the register EVENTSGPIOSET.

To override GPIO input states, set bit GPI.LOGIC[n].

Control input

For a pin to function as a control input, write 0 in bit GPI.INPUT. Debounce is set in register GPIO.DEBOUNCE[n]. The following components can be controlled through GPIO once enabled in the corresponding register.

LOADSW – Registers LDSW1GPISEL or LDSW2GPISEL
BUCK – Register BUCKENCTRL
BUCK forced PWM mode – Register BUCKPWMCTRL
BUCK VOUT[n] voltage level selection for active and retention modes – Register BUCKVRETCTRL
Second reset button – GPIO0 only, see Two-button reset

Output

The GPIO outputs can be configured as logic outputs or open drain outputs in register GPIO.OPEN.DRAIN[n].

When setting a GPIO as output, the host software disables any pull-up or pull-down on that GPIO. After a reset, the default is for pull-down to be enabled.

GPIO can be used as a general purpose output by setting bit GPO.LOGIC[n].

GPIO can be used as an interrupt by setting one or more from the following registers:

GPIO can indicate a watchdog event when the watchdog expires. Select bit GPO.RESET to enable watchdog events.

An imminent power failure warning can be set by selecting bit GPO.PLW.

Drive strength can be selected in register GPIODRIVE[0] and is available from 1 mA (default) to 6 mA. Weak pull-up and pull-down resistors are available in the following registers:

Electrical specification

Table 1. GPIO electrical specification
Symbol	Description	Min.	Typ.	Max.	Unit
V_IH	Input high voltage	0.7 x VDDIO		VDDIO	V
V_IL	Input low voltage	AVSS		0.3 x VDDIO	V
PU_GPIO	Weak pull-up resistor		500		kΩ
PD_GPIO	Weak pull-down resistor		500		kΩ
DB_GPIO	Input debounce time (DEBOUNCE1=1)		20		ms

Registers

Instances

Instance	Base address	Description
GPIOS	0x00000600	GPIO Registers GPIOS register map

Instance

Base address

Description

GPIOS

0x00000600

GPIO Registers

GPIOS register map

Register overview

Register	Offset	Description
GPIOMODE[0]	0x0	GPIO Mode Configuration
GPIOMODE[1]	0x1	GPIO Mode Configuration
GPIOMODE[2]	0x2	GPIO Mode Configuration
GPIOMODE[3]	0x3	GPIO Mode Configuration
GPIOMODE[4]	0x4	GPIO Mode Configuration
GPIODRIVE[0]	0x5	GPIO Drive strength Configuration
GPIODRIVE[1]	0x6	GPIO Drive strength Configuration
GPIODRIVE[2]	0x7	GPIO Drive strength Configuration
GPIODRIVE[3]	0x8	GPIO Drive strength Configuration
GPIODRIVE[4]	0x9	GPIO Drive strength Configuration
GPIOPUEN[0]	0xA	GPIO Pull-up Enable Configuration
GPIOPUEN[1]	0xB	GPIO Pull-up Enable Configuration
GPIOPUEN[2]	0xC	GPIO Pull-up Enable Configuration
GPIOPUEN[3]	0xD	GPIO Pull-up Enable Configuration
GPIOPUEN[4]	0xE	GPIO Pull-up Enable Configuration
GPIOPDEN[0]	0xF	GPIO Pull-down Enable Configuration
GPIOPDEN[1]	0x10	GPIO Pull-down Enable Configuration
GPIOPDEN[2]	0x11	GPIO Pull-down Enable Configuration
GPIOPDEN[3]	0x12	GPIO Pull-down Enable Configuration
GPIOPDEN[4]	0x13	GPIO Pull-down Enable Configuration
GPIOOPENDRAIN[0]	0x14	GPIO Open Drain Configuration
GPIOOPENDRAIN[1]	0x15	GPIO Open Drain Configuration
GPIOOPENDRAIN[2]	0x16	GPIO Open Drain Configuration
GPIOOPENDRAIN[3]	0x17	GPIO Open Drain Configuration
GPIOOPENDRAIN[4]	0x18	GPIO Open Drain Configuration
GPIODEBOUNCE[0]	0x19	GPIO Debounce Configuration
GPIODEBOUNCE[1]	0x1A	GPIO Debounce Configuration
GPIODEBOUNCE[2]	0x1B	GPIO Debounce Configuration
GPIODEBOUNCE[3]	0x1C	GPIO Debounce Configuration
GPIODEBOUNCE[4]	0x1D	GPIO Debounce Configuration
GPIOSTATUS	0x1E	GPIO Status from GPIO Pads

GPIOMODE[0]

Address offset: 0x0

GPIO Mode Configuration

Bit number						7	6	5	4	3	2	1	0
ID										A	A	A	A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	RW	GPIOMODE			Config for GPIO mode selection
			GPIINPUT	0	GPI Input
			GPILOGIC1	1	GPI Logic1
			GPILOGIC0	2	GPI Logic0
			GPIEVENTRISE	3	GPI Rising Edge Event
			GPIEVENTFALL	4	GPI Falling Edge Event
			GPOIRQ	5	GPO Interrupt
			GPORESET	6	GPO Reset
			GPOPLW	7	GPO PwrLossWarn
			GPOLOGIC1	8	GPO Logic1
			GPOLOGIC0	9	GPO Logic0

GPIOMODE[1]

Address offset: 0x1

GPIO Mode Configuration

Bit number						7	6	5	4	3	2	1	0
ID										A	A	A	A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	RW	GPIOMODE			Config for GPIO mode selection
			GPIINPUT	0	GPI Input
			GPILOGIC1	1	GPI Logic1
			GPILOGIC0	2	GPI Logic0
			GPIEVENTRISE	3	GPI Rising Edge Event
			GPIEVENTFALL	4	GPI Falling Edge Event
			GPOIRQ	5	GPO Interrupt
			GPORESET	6	GPO Reset
			GPOPLW	7	GPO PwrLossWarn
			GPOLOGIC1	8	GPO Logic1
			GPOLOGIC0	9	GPO Logic0

GPIOMODE[2]

Address offset: 0x2

GPIO Mode Configuration

Bit number						7	6	5	4	3	2	1	0
ID										A	A	A	A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	RW	GPIOMODE			Config for GPIO mode selection
			GPIINPUT	0	GPI Input
			GPILOGIC1	1	GPI Logic1
			GPILOGIC0	2	GPI Logic0
			GPIEVENTRISE	3	GPI Rising Edge Event
			GPIEVENTFALL	4	GPI Falling Edge Event
			GPOIRQ	5	GPO Interrupt
			GPORESET	6	GPO Reset
			GPOPLW	7	GPO PwrLossWarn
			GPOLOGIC1	8	GPO Logic1
			GPOLOGIC0	9	GPO Logic0

GPIOMODE[3]

Address offset: 0x3

GPIO Mode Configuration

Bit number						7	6	5	4	3	2	1	0
ID										A	A	A	A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	RW	GPIOMODE			Config for GPIO mode selection
			GPIINPUT	0	GPI Input
			GPILOGIC1	1	GPI Logic1
			GPILOGIC0	2	GPI Logic0
			GPIEVENTRISE	3	GPI Rising Edge Event
			GPIEVENTFALL	4	GPI Falling Edge Event
			GPOIRQ	5	GPO Interrupt
			GPORESET	6	GPO Reset
			GPOPLW	7	GPO PwrLossWarn
			GPOLOGIC1	8	GPO Logic1
			GPOLOGIC0	9	GPO Logic0

GPIOMODE[4]

Address offset: 0x4

GPIO Mode Configuration

Bit number						7	6	5	4	3	2	1	0
ID										A	A	A	A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	RW	GPIOMODE			Config for GPIO mode selection
			GPIINPUT	0	GPI Input
			GPILOGIC1	1	GPI Logic1
			GPILOGIC0	2	GPI Logic0
			GPIEVENTRISE	3	GPI Rising Edge Event
			GPIEVENTFALL	4	GPI Falling Edge Event
			GPOIRQ	5	GPO Interrupt
			GPORESET	6	GPO Reset
			GPOPLW	7	GPO PwrLossWarn
			GPOLOGIC1	8	GPO Logic1
			GPOLOGIC0	9	GPO Logic0

GPIODRIVE[0]

Address offset: 0x5

GPIO Drive strength Configuration

Bit number						7	6	5	4	3	2	1	0
ID													A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	RW	GPIODRIVE			Config for GPIO drive strength
			1MA	0	1mA
			6MA	1	6mA

GPIODRIVE[1]

Address offset: 0x6

GPIO Drive strength Configuration

Bit number						7	6	5	4	3	2	1	0
ID													A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	RW	GPIODRIVE			Config for GPIO drive strength
			1MA	0	1mA
			6MA	1	6mA

GPIODRIVE[2]

Address offset: 0x7

GPIO Drive strength Configuration

Bit number						7	6	5	4	3	2	1	0
ID													A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	RW	GPIODRIVE			Config for GPIO drive strength
			1MA	0	1mA
			6MA	1	6mA

GPIODRIVE[3]

Address offset: 0x8

GPIO Drive strength Configuration

Bit number						7	6	5	4	3	2	1	0
ID													A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	RW	GPIODRIVE			Config for GPIO drive strength
			1MA	0	1mA
			6MA	1	6mA

GPIODRIVE[4]

Address offset: 0x9

GPIO Drive strength Configuration

Bit number						7	6	5	4	3	2	1	0
ID													A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	RW	GPIODRIVE			Config for GPIO drive strength
			1MA	0	1mA
			6MA	1	6mA