Samsung S3C2440A - Manual (Page 418)

ADC AND TOUCH SCREEN INTERFACE S3C2440A RISC MICROPROCESSOR
16-6
ADC TOUCH SCREEN CONTROL REGISTER (ADCTSC)
Register Address R/W Description Reset Value
ADCTSC 0x5800004 R/W ADC Touch Screen Control Register 0x58
ADCTSC Bit Description Initial State
UD_SEN [8] Detect Stylus Up or Down status.
0 = Detect Stylus Down Interrupt Signal.
1 = Detect Stylus Up Interrupt Signal. 0
YM_SEN [7] YM Switch Enable
0 = YM Output Driver Disable.
1 = YM Output Driver Enable. 0
YP_SEN [6] YP Switch Enable
0 = YP Output Driver Enable.
1 = YP Output Driver Disable. 1
XM_SEN [5] XM Switch Enable
0 = XM Output Driver Disable.
1 = XM Output Driver Enable. 0
XP_SEN [4] XP Switch Enable
0 = XP Output Driver Enable.
1 = XP Output Driver Disable. 1
PULL_UP [3] Pull-up Switch Enable
0 = XP Pull-up Enable.
1 = XP Pull-up Disable. 1
AUTO_PST [2] Automatically sequencing conversion of X-Position and Y-Position
0 = Normal ADC conversion.
1 = Auto Sequential measurement of X-position, Y-position. 0
XY_PST [1:0] Manually measurement of X-Position or Y-Position.
00 = No operation mode
01 = X-position measurement
10 = Y-position measurement
11 = Waiting for Interrupt Mode
0
NOTE: 1) While waiting for Touch screen Interrupt, XP_SEN bit should be set to ‘1’(XP Output disable)
and PULL_UP bit should be set to ‘0’(XP Pull-up enable).
2) AUTO_PST bit should be set ‘1’ only in Automatic & Sequential X/Y Position conversion.
3) XP, YP should be disconnected with GND source during sleep mode to avoid leakage current.
Because XP, YP will be maintained as 'H' states in sleep mode.
Touch screen pin conditions in X/Y position conversion.
XP XM YP YM ADC ch. select
X Position Vref GND Hi-Z Hi-Z YP
Y Position Hi-Z Hi-Z Vref GND XP