COP413C datasheet(9/16 Pages) NSC

9 / 16 page

Functional Description (Continued)

HALT MODE

The COP413C is a

fully static circuit therefore the user may

stop the system oscillator at any time to halt the chip The

chip may be halted by the HALT instruction Once in the

HALT mode the internal circuitry does not receive any clock

signal and is therefore frozen in the exact state it was in

when halted All information is retained until continuing The

HALT mode is the minimum power dissipation state

The HALT mode may be entered into by program control

(HALT instruction) which forces CKO to a logic ‘‘1’’ state

The circuit can be awakened only by the RESET function

POWER DISSIPATION

The lowest power drain is when the clock is stopped As the

frequency increases so does current Current is also lower

at lower operating voltages Therefore to minimize power

consumption the user should run at the lowest speed and

voltage that his application will allow The user should take

care that all pins swing to full supply levels to ensure that

outputs are not loaded down and that inputs are not at

some intermediate level which may draw current Any input

with a slow rise or fall time will draw additional current A

crystal- or resonator-generated clock will draw more than a

square-wave input An RC oscillator will draw even more

current since the input is a slow rising signal

If using an external squarewave oscillator the following

equation can be used to calculate the COP413C current

drain

Ic e Iq a (V c 20 c Fi) a (V c 1280 c FlDv)

where Ic e chip current drain in microamps

Iq e quiescent leakage current (from curve)

Fl e CKI frequency in megahertz

V e chip VCC in volts

Dv e divide by option selected

For example at 5V VCC and 400 kHz (divide by 8)

Ic e 30 a (5 c 20 c 04) a (5 c 1280 c 048)

Ic e 30 a 40 a 320 e 390 mA

OSCILLATOR OPTIONS

There are two options available that define the use of CKI

and CKO

a Cyrstal-Controlled Oscillator CKI and CKO are connect-

ed to an external crystal The instruction cycle time

equals the crystal frequency divided by 8

b RC-Controlled Oscillator CKI is configured as a single

pin RC-controlled Schmitt trigger oscillator The instruc-

tion cycle equals the oscillation frequency divided by 4

CKO is NC

The RC oscillator is not recommended in systems that re-

quire accurate timing or low current The RC oscillator

draws more current than an external oscillator (typically an

additional 100 mA at 5V) However when the part halts it

stops with CKI high and the halt current is at the minimum

TLDD8537 – 6

FIGURE 6 COP413C Oscillator

Crystal or Resonator

RC-Controlled

Oscillator

Crystal

Component Value

Cycle

Value

C1 pF

C2 pF

Time

VCC

32 kHz

220k

20M

5 – 36

15k

82 pF

4 – 9 ms

45V COP413CH Only

455 kHz

10M

30k

82 pF

8 – 16 ms

45V COP413CH Only

2000 MHz

6 – 36

47k

100 pF

16 – 32 ms

30 to 45V COP413C Only

56k

100 pF

16 – 32 ms

45V

Note 15k s R s 150k

50 pF s C s 150 pF

COP413C Datasheet(PDF) 9 Page - National Semiconductor (TI)

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