AT89C52 View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

AT89C52

8-Bit Microcontroller with 8K Bytes Flash

Atmel Corporation 

Figure 3. Timer 2 Auto Reload Mode (DCEN = 1)

(DOWN COUNTING RELOAD VALUE)

0FFH 0FFH

TOGGLE

EXF2

OSC

÷12

T2 PIN

C/T2 = 0

C/T2 = 1

TH2

CONTROL

TR2

OVERFLOW

TL2

RCAP2H RCAP2L

(UP COUNTING RELOAD VALUE)

TF2

TIMER 2

INTERRUPT

COUNT

DIRECTION

1=UP

0=DOWN

Figure 4. Timer 2 in Baud Rate Generator Mode

T2EX PIN

TIMER 1 OVERFLOW

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

OSC

÷2

C/T2 = 0

T2 PIN

T2EX PIN

C/T2 = 1

TRANSITION

DETECTOR

TH2

TL2

CONTROL

TR2

RCAP2H RCAP2L

CONTROL

EXEN2

EXF2

÷2

"0" "1"

SMOD1

"1" "0"

"1" "0"

TIMER 2

INTERRUPT

RCLK

÷ 16

Rx

CLOCK

TCLK

÷ 16

Tx

CLOCK

4-68

AT89C52

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