AK4184 Datasheet, PDF (29/36 Pages) Asahi Kasei Microsystems – TSC with Keypad Scanner and GPIO Expander

[AK4184]
■ Power Down Register (PAGE 1)
The power down register determines the power down control of the keypad scanner block and touch screen block. The
power down state in the touch screen block (TPPD bit = “1”) holds all of the touch panel driver switches off, so that
current cannot flow through the touch panel. The pen interrupt function is disabled and the PENIRQN pin always
stays “H”, effective for reducing power consumption of the touch screen block.
A power down state in the keypad scanner block (KPPD bit = “1”) holds all the C1 ~ C6 pins outputs “L”. By setting
this bit = “1” stops key scanning and clears the keypad data register (KPDATA1, KPDATA2). The keypad function is
restored after the keypad scanner block is powered up. The keypad interrupt is disabled at power-down.
The power down control register format is shown here.
Addr NAME D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1
D0
08H PDCTRL 0
0
0
0
0
0 0 0 0 0 0 0 0 0 KPPD TPPD
Table 37. Power Down Register Format
Bits Name Description
15:2
Reserved
1 _{KPPD Enable keypad block power up/down}
0 : power up(default)
1 : power down
0 _{TPPD Enable the touch screen control block power up/down}
0 : power up(default)
1 : power down
Table 38. Power Down Register
MS0603-E-00
29
2007/04