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At89c51rc – Rainbow Electronics AT89C51RC User Manual

Page 11

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AT89C51RC

11

Figure 4. Timer 2 Auto Reload Mode (DCEN = 1)

Figure 5. Timer 2 in Baud Rate Generator Mode

OSC

EXF2

TF2

T2EX PIN

COUNT
DIRECTION
1=UP
0=DO

T2 PIN

TR2

CONTROL

OVERFLOW

TOGGLE

TIMER 2

INTERRUPT

12

RCAP2L

RCAP2H

0FFH

0FFH

TH2

TL2

C/T2 = 0

C/T2 = 1

(DOWN COUNTING RELOAD VALUE)

(UP COUNTING RELOAD VALUE)

OSC

SMOD1

RCLK

TCLK

Rx

CLOCK

Tx

CLOCK

T2EX PIN

T2 PIN

TR2

CONTROL

"1"

"1"

"1"

"0"

"0"

"0"

TIMER 1 OVERFLOW

NOTE: OSC. FREQ. IS DIVIDED BY 2, NOT 12

TIMER 2

INTERRUPT

2

2

16

16

RCAP2L

RCAP2H

TH2

TL2

C/T2 = 0

C/T2 = 1

EXF2

CONTROL

TRANSITION

DETECTOR

EXEN2

ч

ч

ч

ч