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S3C6400 RISC MICROPROCESSOR
FUNCTION DESCRIPTIONS
A/D Conversion Time
When the GCLK frequency is 50MHz and the prescaler value is 49, total 10-bit conversion time is as follows.
A/D converter freq. = 50MHz/(49+1) = 1MHz
Conversion time = 1/(1MHz / 5cycles) = 1/200KHz = 5 us
Note:
This A/D converter was designed to operate at maximum 2.5MHz clock, so the conversion rate can go up to 500 KSPS.
Touch Screen Interface Mode
1. Normal Conversion Mode
Single Conversion Mode is most likely used for General Purpose ADC Conversion. This mode can be initialized
by setting the ADCCON (ADC Control Register) and completed with read and write to the ADCDAT0 (ADC
Data Register 0).
2. Separate X/Y position conversion Mode
Touch Screen Controller can be operated by one of two Conversion Modes. Separate X/Y Position Conversion
Mode is operated in following method:
X-Position Mode writes X-Position Conversion Data to ADCDAT0, therefore Touch Screen Interface generates
the Interrupt source to Interrupt Controller. Y-Position Mode writes Y-Position Conversion Data to ADCDAT1,
therefore Touch Screen Interface generates the Interrupt source to Interrupt Controller.
3. Auto(Sequential) X/Y Position Conversion Mode
Auto(Sequential) X/Y Position Conversion Mode is operated in the following method: Touch Screen Controller
sequentially converts X-Position and Y-Position that is touched. After Touch controller writes X-measurement
data to ADCDAT0 and writes Y-measurement data to ADCDAT1, Touch Screen Interface generates Interrupt
source to Interrupt Controller in Auto Position Conversion Mode.
4. Waiting for Interrupt Mode
Touch Screen Controller generates wake-up (WKU) signal when the system is in STOP mode (Power Down).
The Waiting for Interrupt Mode of Touch Screen Controller must be set state of Pads(XP, XM, YP, YM) in
Touch Screen Interface.
After Touch Screen Controller generates Wake-Up signal (INT_WKU), waiting for interrupt Mode must be
cleared. (XY_PST sets to the No operation Mode)
Standby Mode
Standby mode is activated when ADCCON [2] is set to '1'. In this mode, A/D conversion operation is halted and
ADCDAT0, ADCDAT1 register contains the previous converted data.
Preliminary product information describe products that are in development,
for which full characterization data and associated errata are not yet available.
Specifications and information herein are subject to change without notice.
ADC AND TOUCH SCREEN INTERFACE
39-3
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