Figure 3.
Timer 2 Auto Reload Mode (DCEN = 1)
(DOWN COUNTING RELOAD VALUE)
0FFH
0FFH
TOGGLE
EXF2
OSC
梅
12
OVERFLOW
C/T2 = 0
TH2
CONTROL
TR2
C/T2 = 1
TIMER 2
INTERRUPT
RCAP2H RCAP2L
(UP COUNTING RELOAD VALUE)
COUNT
DIRECTION
1=UP
0=DOWN
TL2
TF2
T2 PIN
T2EX PIN
Figure 4.
Timer 2 in Baud Rate Generator Mode
TIMER 1 OVERFLOW
梅
2
"0"
NOTE: OSC. FREQ. IS DIVIDED BY 2, NOT 12
SMOD1
OSC
"1"
梅
2
C/T2 = 0
"1"
TH2
CONTROL
TR2
C/T2 = 1
"1"
"0"
TCLK
Tx
CLOCK
TL2
RCLK
"0"
Rx
CLOCK
梅
16
T2 PIN
RCAP2H RCAP2L
TRANSITION
DETECTOR
T2EX PIN
CONTROL
EXEN2
EXF2
TIMER 2
INTERRUPT
梅
16
4-68
AT89C52