Datasheet

17
3286P–MICRO–3/10
AT89S8253
value in RCAP2H and RCAP2L to be reloaded into the timer registers, TH2 and TL2,
respectively.
A logic 0 at T2EX makes Timer 2 count down. The timer underflows when TH2 and TL2 equal
the values stored in RCAP2H and RCAP2L. The underflow sets the TF2 bit and causes 0FFFFH
to be reloaded into the timer registers.
The EXF2 bit toggles whenever Timer 2 overflows or underflows and can be used as a 17th bit
of resolution. In this operating mode, EXF2 does not flag an interrupt.
Figure 10-2. Timer 2 in Auto Reload Mode (DCEN = 0)
Figure 10-3. Timer 2 Auto Reload Mode (DCEN = 1 Timer 2 Auto Reload Mode (DCEN = 1)