System Control Module

9.1.1.5GPIO Edge Detect Status Register (GEDR)

The GPIO edge detect status register (GEDR) contains 28 status bits that correspond to the 28 GPIO port pins. When an edge detect occurs on a pin that matches the type of edge programmed in the GRER and/or GFER registers, the corresponding status bit is set in GEDR. Once a GEDR bit is set, the CPU must clear it. GEDR status bits are cleared by writing a one to them. Writing a zero to a GEDR status bit has no effect.

Each edge detect that sets the corresponding GEDR status bit for GPIO pins 0 – 27 can trigger an interrupt request. Pins 27 – 11 together form a group that can cause one interrupt request to be triggered when any one of the GEDR status bits 27 – 11 is set. Each of GPIO pins 10 – 0 causes an independent first-level interrupt. See the Section 9.2, “Interrupt Controller” on page 9-11for a description of the programming of GPIO interrupts. The following table shows a summary of GEDR; a question mark indicates that the values are unknown at reset.

Bit

R/W

Reset

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reserved

 

ED27

ED26

ED25

ED24

ED23

ED22

ED21

ED20

ED19

ED18

ED17

ED16

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

0

0

0

?

?

?

?

?

?

?

?

?

?

?

?

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R/W

ED15

ED14

ED13

ED12

ED11

ED10

ED9

ED8

ED7

ED6

ED5

ED4

ED3

ED2

ED1

ED0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reset

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

Bit

Name

 

Description

 

 

 

{n}

ED{n}

GPIO edge detect status n (where n = 0 through 27).

 

 

0

– No edge detect has occurred on pin as specified in GRER and/or GFER.

 

 

1

– Edge detect has occurred on pin as specified in GRER and/or GFER.

 

 

 

31..28

Reserved.

 

 

 

 

SA-1100 Developer’s Manual

9-7

Page 77
Image 77
Intel SA-1100 manual Gpio Edge Detect Status Register Gedr