MK712

Touch Screen Controller

MDS 712 I

5

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

Rate Register (Register 7) Programming

Count

P.P.S.

Count

P.P.S.

Count

P.P.S.

0 to 8

Not Permitted

28

95

100

32

9

197

29

93

105

31

10

187

30

90

110

29

11

177

31

88

115

28

12

169

32

86

120

27

13

161

33

84

125

26

14

154

34

82

130

25

15

147

35

80

135

24

16

141

40

72

140

24

17

136

45

65

145

23

18

131

50

60

150

22

19

126

55

55

155

21

20

122

60

51

165

20

21

118

65

47

175

19

22

114

70

44

185

18

23

110

75

42

195

17

24

107

80

39

205

16

25

104

85

37

225

15

26

101

90

35

235

14

27

98

95

34

255

13

P.P.S. = Points Per Second. With a 14.318 MHz clock.

The formula for determining P.P.S. is:

P.P.S. =

35716 + (4096 x COUNT)

fin

Where fin is the frequency

of the CLKIN input.

Initializing the MK712

The interrupt on the MK712 can only be cleared by reading a register or by writing register 6 to the

power down condition. After a fault condition, initialize the MK712 by writing register 6 to zero and

then writing register 6 to the desired value. This will always clear pending interrupts.

Calculating Points Per Second

On application of power, an internal reset is generated that clears all bits in registers 0, 1, and 6. Register 7 is

set to 32 giving a rate of 86 PPS. Note that clearing register 6 puts the IC into the power down condition.

Power-On Reset