GPIO — General purpose input/output

The general purpose input/output (GPIO) is organized as one port with up to 32 I/Os (dependent on package) enabling access and control of up to 32 pins through one port. Each GPIO can be accessed individually.

GPIO has the following user-configurable features:

The GPIO Port peripheral implements up to 32 pins, PIN0 through PIN31. Each of these pins can be individually configured in the PIN_CNF[n] registers (n=0..31).

The following parameters can be configured through these registers:

The PIN_CNF registers are retained registers. See POWER — Power supply chapter for more information about retained registers.

Pin configuration

Pins can be individually configured, through the SENSE field in the PIN_CNF[n] register, to detect either a high level or a low level on their input.

When the correct level is detected on any such configured pin, the sense mechanism will set the DETECT signal high. Each pin has a separate DETECT signal, and the default behaviour, as defined by the DETECTMODE register, is that the DETECT signal from all pins in the GPIO Port are combined into a common DETECT signal that is routed throughout the system, which then can be utilized by other peripherals, see Figure 1. This mechanism is functional in both ON and OFF mode.

Figure 1. GPIO Port and the GPIO pin details

Figure 1 illustrates the GPIO port containing 32 individual pins, where PIN0 is illustrated in more detail as a reference. All the signals on the left side of the illustration are used by other peripherals in the system, and therefore, are not directly available to the CPU.

Make sure that a pin is in a level that cannot trigger the sense mechanism before enabling it. Detect will go high immediately if the sense condition configured in the PIN_CNF registers is met when the sense mechanism is enabled. This will trigger a PORT event if the DETECT signal was low before enabling the sense mechanism. See GPIOTE — GPIO tasks and events.

See the following peripherals for more information about how the DETECT signal is used:

  • POWER: uses the DETECT signal to exit from System OFF.
  • GPIOTE: uses the DETECT signal to generate the PORT event.

When a pin's PINx.DETECT signal goes high, a flag will be set in the LATCH register, e.g. when the PIN0.DETECT signal goes high, bit 0 in the LATCH register will be set to '1'.

The LATCH register will only be cleared if the CPU explicitly clears it by writing a '1' to the bit that shall be cleared, i.e. the LATCH register will not be affected by a PINx.DETECT signal being set low.

If the CPU performs a clear operation on a bit in the LATCH register when the associated PINx.DETECT signal is high, the bit in the LATCH register will not be cleared.

The LDETECT signal will be set high when one or more bits in the LATCH register are '1'. The LDETECT signal will be set low when all bits in the LATCH register are successfully cleared to '0'.

If one or more bits in the LATCH register are '1' after the CPU has performed a clear operation on the LATCH registers, a rising edge will be generated on the LDETECT signal, this is illustrated in Figure 2.

Important: The CPU can read the LATCH register at any time to check if a SENSE condition has been met on one or more of the the GPIO pins even if that condition is no longer met at the time the CPU queries the LATCH register. This mechanism will work even if the LDETECT signal is not used as the DETECT signal.

The LDETECT signal is by default not connected to the GPIO port's DETECT signal, but via the DETECTMODE register it is possible to change the behaviour of the GPIO port's DETECT signal from the default behaviour described above to instead be derived directly from the LDETECT signal, see Figure 1. Figure 2 illustrates the DETECT signals behaviour for these two alternatives.

Figure 2. DETECT signal behavior

The input buffer of a GPIO pin can be disconnected from the pin to enable power savings when the pin is not used as an input, see Figure 1. Inputs must be connected in order to get a valid input value in the IN register and for the sense mechanism to get access to the pin.

Other peripherals in the system can attach themselves to GPIO pins and override their output value and configuration, or read their analog or digital input value, see Figure 1.

Selected pins also support analog input signals, see ANAIN in Figure 1. The assignment of the analog pins can be found in Pin assignments.

Important: When a pin is configured as digital input, care has been taken in the nRF52832 design to minimize increased current consumption when the input voltage is between VIL and VIH. However, it is a good practice to ensure that the external circuitry does not drive that pin to levels between VIL and VIH for a long period of time.

GPIO located near the RADIO

Radio performance parameters, such as sensitivity, may be affected by high frequency digital I/O with large sink/source current close to the radio power supply and antenna pins.

Refer to Pin assignments for recommended usage guidelines to maximize radio performance in an application.

Registers

Table 1. Instances
Base address Peripheral Instance Description Configuration
0x50000000 GPIO GPIO

General purpose input and output

 

Deprecated

0x50000000 GPIO P0

General purpose input and output

   
Table 2. Register Overview
Register Offset Description
OUT 0x504

Write GPIO port

 
OUTSET 0x508

Set individual bits in GPIO port

 
OUTCLR 0x50C

Clear individual bits in GPIO port

 
IN 0x510

Read GPIO port

 
DIR 0x514

Direction of GPIO pins

 
DIRSET 0x518

DIR set register

 
DIRCLR 0x51C

DIR clear register

 
LATCH 0x520

Latch register indicating what GPIO pins that have met the criteria set in the PIN_CNF[n].SENSE registers

 
DETECTMODE 0x524

Select between default DETECT signal behaviour and LDETECT mode

 
PIN_CNF[0] 0x700

Configuration of GPIO pins

 
PIN_CNF[1] 0x704

Configuration of GPIO pins

 
PIN_CNF[2] 0x708

Configuration of GPIO pins

 
PIN_CNF[3] 0x70C

Configuration of GPIO pins

 
PIN_CNF[4] 0x710

Configuration of GPIO pins

 
PIN_CNF[5] 0x714

Configuration of GPIO pins

 
PIN_CNF[6] 0x718

Configuration of GPIO pins

 
PIN_CNF[7] 0x71C

Configuration of GPIO pins

 
PIN_CNF[8] 0x720

Configuration of GPIO pins

 
PIN_CNF[9] 0x724

Configuration of GPIO pins

 
PIN_CNF[10] 0x728

Configuration of GPIO pins

 
PIN_CNF[11] 0x72C

Configuration of GPIO pins

 
PIN_CNF[12] 0x730

Configuration of GPIO pins

 
PIN_CNF[13] 0x734

Configuration of GPIO pins

 
PIN_CNF[14] 0x738

Configuration of GPIO pins

 
PIN_CNF[15] 0x73C

Configuration of GPIO pins

 
PIN_CNF[16] 0x740

Configuration of GPIO pins

 
PIN_CNF[17] 0x744

Configuration of GPIO pins

 
PIN_CNF[18] 0x748

Configuration of GPIO pins

 
PIN_CNF[19] 0x74C

Configuration of GPIO pins

 
PIN_CNF[20] 0x750

Configuration of GPIO pins

 
PIN_CNF[21] 0x754

Configuration of GPIO pins

 
PIN_CNF[22] 0x758

Configuration of GPIO pins

 
PIN_CNF[23] 0x75C

Configuration of GPIO pins

 
PIN_CNF[24] 0x760

Configuration of GPIO pins

 
PIN_CNF[25] 0x764

Configuration of GPIO pins

 
PIN_CNF[26] 0x768

Configuration of GPIO pins

 
PIN_CNF[27] 0x76C

Configuration of GPIO pins

 
PIN_CNF[28] 0x770

Configuration of GPIO pins

 
PIN_CNF[29] 0x774

Configuration of GPIO pins

 
PIN_CNF[30] 0x778

Configuration of GPIO pins

 
PIN_CNF[31] 0x77C

Configuration of GPIO pins

 

OUT

Address offset: 0x504

Write GPIO port

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Id f e d c b a Z Y X W V U T S R Q P O N M L K J I H G F E D C B A
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Id RW Field Value Id Value Description
A RW

PIN0

   

Pin 0

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

B RW

PIN1

   

Pin 1

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

C RW

PIN2

   

Pin 2

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

D RW

PIN3

   

Pin 3

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

E RW

PIN4

   

Pin 4

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

F RW

PIN5

   

Pin 5

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

G RW

PIN6

   

Pin 6

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

H RW

PIN7

   

Pin 7

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

I RW

PIN8

   

Pin 8

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

J RW

PIN9

   

Pin 9

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

K RW

PIN10

   

Pin 10

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

L RW

PIN11

   

Pin 11

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

M RW

PIN12

   

Pin 12

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

N RW

PIN13

   

Pin 13

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

O RW

PIN14

   

Pin 14

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

P RW

PIN15

   

Pin 15

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

Q RW

PIN16

   

Pin 16

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

R RW

PIN17

   

Pin 17

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

S RW

PIN18

   

Pin 18

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

T RW

PIN19

   

Pin 19

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

U RW

PIN20

   

Pin 20

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

V RW

PIN21

   

Pin 21

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

W RW

PIN22

   

Pin 22

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

X RW

PIN23

   

Pin 23

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

Y RW

PIN24

   

Pin 24

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

Z RW

PIN25

   

Pin 25

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

a RW

PIN26

   

Pin 26

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

b RW

PIN27

   

Pin 27

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

c RW

PIN28

   

Pin 28

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

d RW

PIN29

   

Pin 29

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

e RW

PIN30

   

Pin 30

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

f RW

PIN31

   

Pin 31

     

Low

0

Pin driver is low

     

High

1

Pin driver is high

 

OUTSET

Address offset: 0x508

Set individual bits in GPIO port

Read: reads value of OUT register.

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Id f e d c b a Z Y X W V U T S R Q P O N M L K J I H G F E D C B A
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Id RW Field Value Id Value Description
A RW

PIN0

   

Pin 0

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

B RW

PIN1

   

Pin 1

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

C RW

PIN2

   

Pin 2

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

D RW

PIN3

   

Pin 3

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

E RW

PIN4

   

Pin 4

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

F RW

PIN5

   

Pin 5

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

G RW

PIN6

   

Pin 6

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

H RW

PIN7

   

Pin 7

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

I RW

PIN8

   

Pin 8

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

J RW

PIN9

   

Pin 9

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

K RW

PIN10

   

Pin 10

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

L RW

PIN11

   

Pin 11

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

M RW

PIN12

   

Pin 12

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

N RW

PIN13

   

Pin 13

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

O RW

PIN14

   

Pin 14

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

P RW

PIN15

   

Pin 15

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

Q RW

PIN16

   

Pin 16

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

R RW

PIN17

   

Pin 17

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

S RW

PIN18

   

Pin 18

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

T RW

PIN19

   

Pin 19

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

U RW

PIN20

   

Pin 20

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

V RW

PIN21

   

Pin 21

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

W RW

PIN22

   

Pin 22

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

X RW

PIN23

   

Pin 23

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

Y RW

PIN24

   

Pin 24

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

Z RW

PIN25

   

Pin 25

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

a RW

PIN26

   

Pin 26

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

b RW

PIN27

   

Pin 27

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

c RW

PIN28

   

Pin 28

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

d RW

PIN29

   

Pin 29

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

e RW

PIN30

   

Pin 30

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

f RW

PIN31

   

Pin 31

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Set

1

Write: writing a '1' sets the pin high; writing a '0' has no effect

 

OUTCLR

Address offset: 0x50C

Clear individual bits in GPIO port

Read: reads value of OUT register.

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Id f e d c b a Z Y X W V U T S R Q P O N M L K J I H G F E D C B A
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Id RW Field Value Id Value Description
A RW

PIN0

   

Pin 0

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

B RW

PIN1

   

Pin 1

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

C RW

PIN2

   

Pin 2

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

D RW

PIN3

   

Pin 3

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

E RW

PIN4

   

Pin 4

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

F RW

PIN5

   

Pin 5

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

G RW

PIN6

   

Pin 6

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

H RW

PIN7

   

Pin 7

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

I RW

PIN8

   

Pin 8

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

J RW

PIN9

   

Pin 9

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

K RW

PIN10

   

Pin 10

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

L RW

PIN11

   

Pin 11

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

M RW

PIN12

   

Pin 12

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

N RW

PIN13

   

Pin 13

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

O RW

PIN14

   

Pin 14

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

P RW

PIN15

   

Pin 15

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

Q RW

PIN16

   

Pin 16

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

R RW

PIN17

   

Pin 17

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

S RW

PIN18

   

Pin 18

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

T RW

PIN19

   

Pin 19

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

U RW

PIN20

   

Pin 20

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

V RW

PIN21

   

Pin 21

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

W RW

PIN22

   

Pin 22

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

X RW

PIN23

   

Pin 23

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

Y RW

PIN24

   

Pin 24

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

Z RW

PIN25

   

Pin 25

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

a RW

PIN26

   

Pin 26

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

b RW

PIN27

   

Pin 27

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

c RW

PIN28

   

Pin 28

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

d RW

PIN29

   

Pin 29

     

Low

0

Read: pin driver is low

     

High

1

Read: pin driver is high

     

Clear

1

Write: writing a '1' sets the pin low; writing a '0' has no effect

e RW

PIN30

   

Pin 30

     

Low

0

Read: pin driver is low