7630 datasheet(59/238 Pages) RENESAS

59 / 238 page

1-43

7630 Group User’s Manual

+$5':$5(

CLOCK GENERATING CIRCUIT

The 7630 group is equipped with an internal clock generating circuit.

Please refer to Fig. 48 for a circuit example using a ceramic resona-

tor or quartz crystal oscillator. For the capacitor values, refer to the

manufacturers recommended parameters which depend on each

oscillators characteristics. When using an external clock, input it to

the XIN pin and leave XOUT open.

Fig. 48 Ceramic resonator circuit

Oscillation Control

The 7630 group has two low power modes: the stop and the wait

mode.

Stop mode

The microcomputer enters the stop mode by executing the STP

instruction. The oscillator stops with the internal clock

φ at “H” level.

Timers 1 and 2 will be cascaded and initialized by their reload latches

contents. The count source for timer 1 will be set to f(XIN)/16.

Oscillation is restarted if an external interrupt is accepted or at reset.

When using an external interrupt, the internal clock

φ remains at “H”

level until timer 2 underflows allowing a time-out until the clock oscil-

lation becomes stable. When using reset, a fixed time-out will be gen-

erated allowing oscillation to stabilize.

Wait mode

The microcomputer enters the wait mode by executing the WIT

instruction. The internal clock ø stops at “H” level while the oscillator

keeps running.

Recovery from wait mode can be done in the same way as from stop

mode. However, the time-out period mentioned above is not required

to return from wait-mode, thus no such time-out mechanism has

been implemented.

Note: Set the interrupt enable bit of the interrupt source to be used to

return from stop or wait mode to “1” before executing STP or WIT

instruction.

Fig. 49 Block diagram of clock generating circuit

CIN

COUT

XIN

XOUT

WIT

STP

XIN

XOUT

1/2

1/4

CPUM6

Interrupt request

Interrupt disable flag

RESET

Delay

STP

Internal clock

for

peripherals

Internal clock

for CPU

Oscillator countdown

(timer 1 and 2)

“1”

“0”

CLOCK GENERATING CIRCUIT

7630 датащи(PDF) 59 Page - Renesas Technology Corp

7630 датащи(HTML) 59 Page - Renesas Technology Corp

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL