CDP1805AC View Datasheet(PDF) - Intersil

Part Name

Description

Manufacturer

CDP1805AC

CMOS 8-Bit Microprocessor with On-Chip RAM and Counter/Timer

Intersil 

CDP1805AC, CDP1806AC

STPC

TPA

EF1

EF2

DTC

GEC

R

÷ 32

STM

SPMI

SCMI

SPM2

SCM2

INH

OUT

COUNTER

UNDERFLOW

8-BIT

DOWN

COUNTER

LOAD

ETQ

LDC

READ

TO INTERRUPT LATCH

Q OUTPUT

C

Q

Q FF

D

Q

FIGURE 7. TIMER/COUNTER DIAGRAM

Because of the Schmitt Trigger input, an RC oscillator can

be used as shown in Figure 9. The frequency is approxi-

mately 1/RC (see Figure 10).

RF

1MΩ

CLOCK† 1

39 XTAL †

VDD = 5V AT 25oC

10M

1M

100K

C

=

C=

1µpF

0.1µF

C

=

C=

0.01µF

C=

1000pF

100pF

CIN

15pF

XTAL

5MHz PARALLEL

RESONANT

CRYSTAL

COUT

27pF

†Pin numbers refer to 40 pin DIP.

FIGURE 8. TYPICAL 5MHz CRYSTAL OSCILLATOR

R

CLOCK† 1

C

39 XTAL †

10K

1

10

100

1K

10K 100K

1M

FREQUENCY (Hz)

FIGURE 10. NOMINAL COMPONENT VALUES AS A FUNCTION

OF FREQUENCY FOR THE RC OSCILLATOR

CLEAR

L

L

H

H

CONTROL MODES

WAIT

L

H

L

H

MODE

Not Allowed

Reset

Pause

Run

†Pin numbers refer to 40 pin DIP.

FIGURE 9. RC NETWORK FOR OSCILLATOR

14

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