s3c2410a Samsung Semiconductor, Inc., s3c2410a Datasheet - Page 412

• Manufacturer Part Number: s3c2410a
• Description: 16/32-bit Risc Arm Microprocessor
• Manufacturer: Samsung Semiconductor, Inc.

ADC AND TOUCH SCREEN INTERFACE
FUNCTION DESCRIPTIONS
A/D Conversion Time
When the PCLK frequency is 50 MHz and the prescaler value is 49, total 10-bit conversion time is given:
Touch Screen Interface Mode
1. Normal Conversion Mode
2. Separate X/Y Position Conversion Mode
16-4
X Position Conversion
Y Position Conversion
A/D converter freq. = 50 MHz/(49+1) = 1 MHz
Conversion time = 1/(1 MHz / 5cycles) = 1/200 kHz = 5 us
This A/D converter is designed to operate at maximum 2.5 MHz clock, so the conversion rate can go up to
500 KSPS.
Normal Conversion Mode (AUTO_PST = 0, XY_PST = 0) is generally used for General Purpose ADC Conversion.
This mode can be initialized by setting the ADCCON and ADCTSC and completed with a read the XPDATA
(Normal ADC) value of ADCDAT0 (ADC Data Register 0).
Separate X/Y Position Conversion Mode is consist of two Conversion Modes: X-Position Mode and Y-Position
Mode.
The first mode is operated in the following way:
X-Position Mode (AUTO_PST = 0 and XY_PST = 1) writes X-position conversion data to XPDATA of ADCDAT0
register. After conversion, The Touch Screen Interface generates the Interrupt source (INT_ADC) to Interrupt
Controller.
Y-Position Mode (AUTO_PST = 0 and XY_PST = 2) writes Y-position conversion data to YPDATA of ADCDAT1.
After the conversion, the Touch Screen Interface also generates the Interrupt source (INT_ADC) to Interrupt
Controller.
Table 16-1. Condition of Touch Screen Panel Pads in Separate X/Y Position Conversion Mode
External Voltage
AIN[7]
XP
NOTE
GND
Hi-Z
XM
External Voltage
AIN[5]
YP
GND
Hi-Z
YM
S3C2410A