Samsung S5PC110 Manual page 1925

S5PC110_UM
7.4 FUNCTION DESCRIPTIONS
7.4.1 A/D CONVERSION TIME
When the PCLK frequency is 66MHz and the prescaler value is 65, total 12-bit conversion time is as follows.
• A/D converter freq. = 66MHz/(65+1) = 1MHz
• Conversion time = 1/(1MHz / 5cycles) = 1/200kHz = 5us
NOTE: This A/D converter was designed to operate at maximum 5MHz clock, so the conversion rate can go up to 1MSPS.
7.4.2 TOUCH SCREEN INTERFACE MODE
1. Normal Conversion Mode (AUTO_PST = 0, XY_PST = 0)
The operation of this mode is same as AIN0~AIN9's. To initialize this mode, set the TSADCCON0 (ADC control
register) and TSCONn (Touch screen control register). The switches and pull-up resistor should be turned off (all
switches are turned off if TSCON0 and TSCON1 are set to 0x58). The converted data can be read out from
TSDATX0 (ADC conversion data X register).
NOTE: TSADCCON1 register is useless in normal conversion mode. Therefore, TSSEL bit of TSADCCON0 register should
be 0. TSADCCON1 register is meaningless if TSSEL bit is 0.
2. Separate X/Y Position Conversion Mode (AUTO_PST = 0, XY_PST = control)
This mode consists of two states, namely, X-position measurement state and Y-position measurement state.
Steps to operate X-position measurement state;
− Set '0x69' to TSCONn.
(XY_PST=1, AUTO_PST=0, PULL_UP disable, XP enable, XM enable, YP disable, YM disable)
− Start conversion by setting TSADCCONn.
− The end of X-position conversion can be notified by interrupt (INT_ADCn).
− Read out the converted data (X-position) from TSDATXn.
Steps to operate Y-position measurement state;
− Set '0x9a' to TSCONn.
(XY_PST=2, AUTO_PST=0, PULL_UP disable XP disable, XM disable, YP enable, YM enable)
− Start conversion by setting TSADCCONn.
− The end of Y-position conversion can be notified by interrupt (INT_ADCn).
− Read out the converted data (Y-position) from TSDATYn.
7 ADC & TOUCH SCREEN INTERFACE
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