Negative Mask Register Port 1/3

The Negative Mask Register for Port 1/3 (base + 2Ah) can be read or written. If bit 4 of the Control/Status Register is low ("0"), Port 1 data is accessed. If bit 4 is high ("1"), Port 3 data will be accessed. The operation of the Negative Mask Register for Port 1/3 is identical to those of Port 0/2.

Negative Mask Register Port 1/3 (Channels 16-31/48-63) (base + 2Ah)

b + 2Ah

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

Read/Write

Ch31

Ch30

Ch29

Ch28

Ch27

Ch26

Ch25

Ch24

Ch23

Ch22

Ch21

Ch20

Ch19

Ch18

Ch17

Ch16

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Read/Write

Ch63

Ch62

Ch61

Ch60

Ch59

Ch58

Ch57

Ch56

Ch55

Ch54

Ch53

Ch52

Ch51

Ch50

Ch49

Ch48

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Debounce Clock

Register Port 0 and

Port 1/ Port 2 and

Port 3

The Debounce Clock Register (base + 2Eh) can be read or written. This register is a mirror image of the Debounce Clock Register at base + 1Eh. Refer to that register for an explanation of its operation.

Debounce Clock Register Port 0 and Port 1/Port 2 and Port 3 (base + 2Eh)

b + 2Eh

15

14

13

 

12

11

 

10

9

8

7

6

5

4

3

 

2

1

 

0

Write

 

 

 

 

 

 

No Effect

 

 

 

 

 

 

 

DEBOUNCE TIME

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Read

 

 

 

Always Returns FFFh

 

 

 

0

0

0

 

DEBOUNCE TIME

 

When BS = 0 in the Status/Control Register, the debounce clock for Port 0 and Port 1 are accessed. Port 0 and Port 1 use the same debounce clock. With BS = 0 any value programmed into or read from this register will be the same as the register at b + 2Eh.

When BS = 1 in the Status/Status Register, the debounce clock for Port 2 and

Port 3 are accessed. Port 2 and Port 3 use the same debounce clock. With BS

=1 any value programmed into or read from this register will be the same as the register at b + 1Eh.

HP E1459A Register Definitions 89