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a. Basic Input Mode

DATA BUS' ~===::::J ____________

b. Basic Output Mode

DATA BUS·

OUTPUT

·DATABUS TIMING IS SHOWN IN FIGURE 7.

Figure 14. Basic 1/0 Timing Waveform

 

LOAD COUNTER FROM CLR --I

 

RELOAD COUNTER FROM CLR -I

I

 

2

I

1

I

 

I

2

I

1

TIMER IN

 

 

 

 

 

 

 

 

 

 

TIMER OUT

 

 

 

 

 

 

 

 

 

 

(PULSE)

 

 

 

\

(NOTE 1)

J "

 

 

 

 

TIMER OUT

\

 

 

 

 

I

I

 

 

 

(SQUARE WAVE)

\

 

(NOTE 1(

 

 

 

 

 

 

 

'--------_..1

 

 

 

 

NOTE 1: THE TIMER OUTPUT IS PERIODIC IF IN AN AUTOMATIC

RELOAD MODE ,!M1 MODE BIT'"')

Figure 15. Timer Output Waveform Countdown from 5 to 1

6·95

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Intel mcs-48 manual Basic Input Mode, Basic Output Mode