MK712

Touch Screen Controller

MDS 712 I

4

Revision 100899

Printed 11/16/00

Integrated Circuit Systems, Inc.•525 Race St.•San Jose•CA•95126•(408)295-9800tel•www.icst.com

I C R O

Register Description

The MK712 register set is designed to be compatible with the Gazelle pen digitizer registers allowing a

software driver for the Gazelle digitizer to be used with the MicroClock MK712. The eight 8-bit registers

are defined below:

STATUS HIGH (1 READ)

Always zero

1 = touch

1 = conversion complete,

cleared on Y-HIGH read

STATUS LOW (0 READ)

NOTE: When the screen is touched bits 4 and 5,

register 0, and bits 2 and 3 of register 1 are all set to one.

Always zero

1 = touch

Always zero

X-LOW (2 READ)

Low order bits of X co-ordinate

Y-LOW (4 READ)

Low order bits of Y co-ordinate

High order bits of Y co-ordinate

Always zero

Count controls frequency of

conversion when periodic

conversions are enabled. See

table on page 5.

NOTE: Bits 2 or 3 and bits 6 or 7 are logically OR’d. For

example writing bit 2 or bit 3 to a one will enable interrupts

on change in touch status.

1 = enable interrupts

1 = interrupt on conversion

complete ( if bit 0 = 1)

1 = interrupt on change in

touch status (if bit 0 = 1)

1 = enable periodic conversions at

rate indicated by RATE register

1 = read one point. Cleared when

conversion complete. Only functions

when bit 4 = 0

0 = powerdown (PD). Conversions,

interrupts and TOUCH output disabled

1 = powerdown (PD). Conversions,

interrupts and TOUCH output

disabled.

X-HIGH (3 READ)

High order bits of X co-ordinate

Always zero

7

1

0

3

2

5

4

6

7

1

0

3

2

5

4

6

7

1

0

3

2

5

4

6

7

1

0

3

2

5

4

6

7

1

0

3

2

5

4

6

RATE (7 R/W)

7

1

0

3

2

5

4

6

1 = interrupt on change in

touch status (if bit 0 = 1)

CONTROL (6 R/W)

7

1

0

3

2

5

4

6

Always zero

Y-HIGH (5 READ)

7

1

0

3

2

5

4

6