AC3 I/O map

Register name

Base address offset

Bit reference

Data

Read / write

'p' axis LO byte

0

7 to 0

2's complement 16 bit count 8000H to 7FFFH

Read only

'p' axis HI byte

1

15 to 8

2's complement 16 bit count 8000H to 7FFFH

Read only

'q' axis LO byte

2

7 to 0

2's complement 16 bit count 8000H to 7FFFH

Read only

'q' axis HI byte

3

15 to 8

2's complement 16 bit count 8000H to 7FFFH

Read only

'r' axis LO byte

4

7 to 0

2's complement 16 bit count 8000H to 7FFFH

Read only

'r' axis HI byte

5

15 to 8

2's complement 16 bit count 8000H to 7FFFH

Read only

Timer LO count

6

7 to 0

16 bit binary count 0000H to FFFFH

Read only 

Timer HI count

7

15 to 8

16 bit binary count 0000H to FFFFH

Read only 

Page selection

8

7 to 0

Selects pages 0, 1 or 2

Read / write 

Not used

9

15 to 8

Reads back 00H

Read only

PICS & interrupted status

10

7 to 0

Bits are set if the condition is true

Read only

PICS & interrupt status register definitions:

 

 

7 to 4 - Not used (logic set to 0)
3 - PICS READ
2 - PICS PDAMP
1 - PICS PPOFF
0 - Interrupt request

 

Not used

11

15 to 8

Reads back 00H

Read only

Acquisition mode select

12

7 to 0

Set the bit to command the function

Read / write

Acquisition mode register definitions:

 

 

7 - Interrupt line select bit 2 (see table 14)
6 - Interrupt line select bit 1 (see table 14)
5 - Interrupt line select bit 0 (see table 14)
4 - Level / shared interuupt mode selection
3 - Not used
2 - Acquisition mode select bit 2 (see table 15)
1 - Acquisition mode select bit 1 (see table 15)
0 - Acquisition mode select bit 0 (see table 15)

 

Register name

Base address offset

Bit reference

Data

Read / write

Command register

13

15 to 8

Write 1' to the relevant bit to activate

Write only 

Command register definitions:

 

 

15 - Not used
14 - Not used
13 - Not used
12 - Not used
11 - AQUIRE data and latch timer count (sets BUSY true until complete)
10 - REQUEST SET PROBE PRESENT
9 - REQUEST RESET OVER_RANGE
8 - RESET TIMER 

 

Status register

14

7 to 0

Bits set to logic if condition TRUE

Read only

Status register definitions:

 

 

7 - Not used (set logic to 0)
6 - BUSY
5 - TIMER OVERFLOW
4 - PROBE PRESENT
3 - OVER-RANGE
2 - 5 V OVERCURRENT
1 - -12 V OVERCURRENT
0 - +12 V OVERCURRENT

 

AC3 identification & functionality version

15

15 to 8

Page 0 returns the value 09H' or 0AH'
Page 2 returns the functionality version #

Read only