Samsung S3C8245 User Manual

Page of 335
S3C8245/P8245/C8249/P8249
WATCH TIMER
13-1
13
WATCH TIMER
OVERVIEW
Watch timer functions include real-time and watch-time measurement and interval timing for the system clock.
To start watch timer operation, set bit1 and bit 6 of the watch timer mode register, WTCON.1and 6, to “1”. After the
watch timer starts and elapses a time, the watch timer interrupt is automatically set to “1”, and interrupt requests
commence in 1.955 ms or 0.125, 0.25 and 0.5-second intervals.
The watch timer can generate a steady 0.5 kHz, 1 kHz, 2 kHz, or 4 kHz signal to the BUZZER output. By setting
WTCON.3 and WTCON.2 to “11b”, the watch timer will function in high-speed mode, generating an interrupt every
1.955 ms. High-speed mode is useful for timing events for program debugging sequences.
The watch timer supplies the clock frequency for the LCD controller (f
LCD
). Therefore, if the watch  timer is disabled,
the LCD controller does not operate.
— Real-time and Watch-time measurement
— Using a main system or subsystem clock source
— Clock source generation for LCD controller
— Buzzer output frequency generator
— Timing tests in high-speed mode