System Control Module

9.1.1.6GPIO Alternate Function Register (GAFR)

The GPIO alternate function register (GAFR) contains 28 control bits that correspond to the 28 GPIO port pins. When the processor sets a bit in the GAFR, the corresponding GPIO pin is switched over to that pin’s alternate function. See the following section for details on alternate functions. This register is cleared to all zeros on all reset conditions.

Bit

R/W

Reset

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reserved

 

AF27

AF26

AF25

AF24

AF23

AF22

AF21

AF20

AF19

AF18

AF17

AF16

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R/W

AF15

AF14

AF13

AF12

AF11

AF10

AF9

AF8

AF7

AF6

AF5

AF4

AF3

AF2

AF1

AF0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

Name

Description

 

 

 

{n}

AF{n}

GPIO alternate function bits (where n = 0 through 27).

 

 

A bit set in this register indicates that the corresponding GPIO pin is to be used for its

 

 

alternate function. A zero in this register indicates that the corresponding GPIO pin is to

 

 

be used for its normal GPIO function.

 

 

 

31..28

Reserved.

 

 

 

9-8

SA-1100 Developer’s Manual

Page 78
Image 78
Intel SA-1100 manual Gpio Alternate Function Register Gafr