MAX1233_05 Datasheet, PDF (24/45 Pages) Maxim Integrated Products – ±15kV ESD-Protected Touch-Screen Controllers Include DAC and Keypad Controller

±15kV ESD-Protected Touch-Screen
Controllers Include DAC and Keypad Controller
Table 17. Keypad Control Register
BIT15
BIT14 BIT13 BIT12 BIT11 BIT10 BIT9 BIT8 BIT7 BIT6 BIT5 BIT4 BIT3 BIT2 BIT1 BIT0
KEYSTS1 KEYSTS0 DBN2 DBN1 DBN0 HLD2 HLD HLD 0
0
0
0
0
0
0
0
Table 18. Keypad Control Register Description
BIT
15 (MSB)
14
13
12
11
10
9
8
[7:0]
NAME
KEYSTS1
KEYSTS0
DBN2
DBN1
DBN0
HLD2
HLD1
HLD0
0
DESCRIPTION
Read: keypad interrupt status; Write: set interrupt initiated keypad scans
Read: keypad scan status; Write: stop keypad scan
Keypad debounce time control
Keypad debounce time control
Keypad debounce time control
Keypad hold time control
Keypad hold time control
Keypad hold time control
Reserved
Table 19. KEYSTS1/KEYSTS0 Functions
KEYSTS1 KEYSTS0
READ FUNCTION
WRITE FUNCTION
No button press detected;
Scans keypad once and waits to detect a button press. Upon
0
0
scan or debounce in progress
detection, issues an interrupt and waits for the host’s instruction
before scanning.
1
0
Button press detected;
Stops any ongoing scan and waits to detect a button press. Upon
scan or debounce in progress detection, issues an interrupt and scans the keypad.
0
1
No button press detected;
data available
Stops any ongoing scan and waits to detect a button press. Upon
detection, issues an interrupt and waits for the host’s instruction
before scanning.
1
1
Button press detected;
data available
Stops any ongoing scan and powers down the button press
detection circuit. No button presses are detected in this mode.
Table 20. Keypad Debounce Time Control
DBN2
0
0
0
0
1
1
1
1
DBN1
0
0
1
1
0
0
1
1
DBN0
0
1
0
1
0
1
0
1
FUNCTION (ms)
Debounce time: 2
Debounce time: 10
Debounce time: 20
Debounce time: 50
Debounce time: 60
Debounce time: 80
Debounce time: 100
Debounce time: 120
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