Samsung S5PC100, User Manual, Page: 601 / 1863

SYSTEM TIMER S5PC100 USER’S MANUAL (REV1.0)
7.2-4
5 DETAILED OPEARATION
Figure 7.2-3 Timer Operation with Always on of Auto-reload
Generally tick interval is fixed after initial setting. And interrupt interval can be changed at run-time. Figure 7.2-3
shows detailed operation of interrupt counter and interrupt counter observation SFR with auto-reload. Each
rectangular shows one tick time. Although interrupt interval is changed, that tick time is fixed. Because tick and
interrupt counter are independent to each other.
Interrupt is asserted at INTCNT value is expired (INTCNT=0). SW can know elapsed time by reading ICNTO.
NOTE: When ICNTB is changed with interrupt manual update (TCON[4]) (* at Figure 7.2-3), the new changed
value is applied to INTCNT (interrupt counter) at that time. When ICNTB is changed without interrupt manual
update (TCON[4]) (@ at Figure 7.2-3), the new changed value is applied to INTCNT (interrupt counter) after
counter is expired.
If auto reload is needed, Interrupt Manual Update (TCON[4]) must be de-asserted, before INTCNT value is
expired (INTCNT=0).
Figure 7.2-4 Timer Operation without Auto Reload (One-shot mode)