Laptop User Manual

ADC AND TOUCH SCREEN INTERFACE S3C2440A RISC MICROPROCESSOR
16-4
Programming Notes
1. The A/D converted data can be accessed by means of interrupt or polling method. With interrupt method
the overall conversion time - from A/D converter start to converted data read - may be delayed because of
the return time of interrupt service routine and data access time. With polling method, by checking the
ADCCON[15] - end of conversion flag-bit, the read time from ADCDAT register can be determined.
2. Another way for starting A/D conversion is provided. After ADCCON[1] - A/D conversion start-by-read
mode-is set to 1, A/D conversion starts simultaneously whenever converted data is read.
XP
X-Tal CLK
is used
X-Conversion
YP
GCLK
is used
Y-Conversion
Pen Touch
Figure 16-2 ADC and Touch Screen Operation signal