Philips Semiconductors
Product specification
80C51 8-bit microcontroller family
4K/8K/16K/32K Flash
89C51/89C52/89C54/89C58
OSC
÷
12
C/T2 = 0
TL2
(8-BITS)
C/T2 = 1
TH2
(8-BITS)
T2 PIN
CONTROL
TR2
RELOAD
TRANSITION
DETECTOR
RCAP2L
RCAP2H
TF2
TIMER 2
INTERRUPT
T2EX PIN
EXF2
CONTROL
EXEN2
SU00067
Figure 4. Timer 2 in Auto-Reload Mode (DCEN = 0)
(DOWN COUNTING RELOAD VALUE)
FFH
FFH
TOGGLE
EXF2
OSC
÷12
C/T2 = 0
OVERFLOW
TL2
TH2
TF2
INTERRUPT
T2 PIN
C/T2 = 1
CONTROL
TR2
COUNT
DIRECTION
1 = UP
0 = DOWN
RCAP2L
RCAP2H
T2EX PIN
(UP COUNTING RELOAD VALUE)
SU00730
Figure 5. Timer 2 Auto Reload Mode (DCEN = 1)
1999 Oct 27
11