AK4184 Datasheet, PDF (22/36 Pages) Asahi Kasei Microsystems – TSC with Keypad Scanner and GPIO Expander

[AK4184]
Keypad Debounce Scan initiated by keypad activity (Initial : KST1 bit="1", KST0 bit="0"
Ry
KEYIRQN
BUSY
CSN
DOUT
KPDATA1,2
State
Key
Detect
Enable
Debounce
Scan
HOLD
Key
Detect
Disable
Debounce
Scan
Key Detect
Enable
then wait
HOLD
Figure 13. Keypad Debounce Scan initiated by key activity
(Key interrupt enable, key scan initiated by key touch)
■ Keypad Control Register (PAGE 1)
The keypad scanner controller is controlled by the Keypad Control register (Table 12), Keypad Mask register (Table
17 ) and Keypad Column register (Table 19). This register controls the key press interrupt (host scan mode or key-press
scan mode), key-press debounce time interval and hold time. The Keypad Mask register is valid for each key masked
after debounce key scan. The Keypad Column Mask register stops a key scan of a selected key column and is disabled
for the detection of key press.
Addr
00H
NAME
KEY
D15
MSB
KST1
D14
KST0
D13 D12 D11 D10 D9
D8 D7 D6 D5 D4 D3 D2 D1 D0
LSB
DBN[2:0]
HLD[2:0]
0000000 0
Table 11. Keypad Control Register Format
Bits Name
15 _KST1
14 _KST0
13:11
10:8
7:0
DBN
HLD
Description
Key Interrupt enable signal
0 : disable
1 : enable
Key scan initiated by Host/Key
0 : scan starts by key-press
1 : scan starts by Host command
Keypad debounce time interval
Keypad hold time control
Reserved
Table 12. Keypad Control Register (Write)
The KST1 and KST0 bits can be read to determine the state of keypad scanner. The KST1 and KST0 bits and their
descriptions are described in Table 13.
KST1
0
0
1
1
KST0 Description
0 No detect
1 Wait for the command initiated by Host
0 Keypad Debounce scan is busy.
1 Data available
Table 13. KST bit (Read)
MS0603-E-00
22
2007/04