
TIMER
S3C3410X RISC MICROPROCESSOR
8-4
OPERATION DESCRIPTION
16-BIT TIMERS (TIMER0, TIMER1 AND TIMER2)
Interval Mode Operation
In interval mode, a match signal should be generated when the counter value is identical to the value written to
the timer data register, TDAT0, TDAT1 and TDAT2. The match signal can generate a timer 0, 1, or 2 match
interrupt and clear the counter value. When a match condition happens, the timer output(TOUT0/1/2) will be
toggled.
Capture Mode Operation
In capture mode, the timer can perform the capturing operation, which is that the counter value is transferred into
the capture register(Timer Data Register) in synchronization with an external trigger. The external triggering
signal for capturing operation is a pre-defined valid edge on the capture input pin. When this valid signal
happens, the counter value in process should be moved into the capture register(Timer Data Register). By using
the capturing function, users can measure the time difference between external events. If a valid trigger signal on
the pin does not happen before the overflow, an overflow interrupt will be generated and the counter value will be
counted from 0000h, again.
Match & Overflow Mode Operation
In this mode, a match signal can be generated when the counter value is identical to the value written to the timer
data register. However, the match signal does not clear the counter even if it can generate a match interrupt as
same as the interval mode. Because it does not clear the counter value, the timer can run up to the overflow of
counter value and generate an overflow interrupt, also. After the overflow of counter value, the counter value will
be counted from 0000h, again.
DMA Mode Operation (Timer 1 Only)
Users can use the DMA to support the Timer 1. The DMA can transfer the data in memory to the TDAT1(Timer
Data Register). When the match interrupt happens, the Timer 1 can request the DMA service to transfer the data
into the TDAT1 register, again. Before the DMA-based operation, users should configure the control information
on DMA, such as TCON1[5:3] to "010", TDAT1, destination address, source address, and so on. This kind of
DMA-based timer operation is very helpful to generate the pre-defined timing event.