5 POWER-DOWN CONTROL

Function

Control bit

"1"

"0"

Default

System clock switch over

CLKCHG(D2)/

OSC3

OSC1

OSC3

 

Power control register(0x40180)

 

 

 

High-speed (OSC3) oscillation ON/OFF control

SOSC3(D1)/

ON

OFF

ON

 

Power control register(0x40180)

 

 

 

System clock division ratio selection

CLKDT(D[7:6])/

"11" = 1/8

1/1

 

Power control register(0x40180)

"10" = 1/4

 

 

 

"01" = 1/2

 

 

 

"00" = 1/1

 

Turning off the prescaler and peripheral circuits

Current consumption can be reduced by turning off the peripheral circuits operating at high speed as much as possible. The peripheral circuits are as follows.

1)Peripheral circuits using the clock generated by the prescaler

16-bit programmable timers 0 to 5 (watchdog timer)

8-bit programmable timers 0 to 5 (DRAM refresh, serial interface)

A/D converter

2)Peripheral circuits using the clock (source clock for prescaler) supplied to the prescaler

16-bit programmable timers 0 to 5 (watchdog timer)

8-bit programmable timers 0 to 5 (DRAM refresh)

A/D converter

Serial interface

Input/output ports

If none of all circuits of the above 1) and 2) need to be used, turn off the prescaler. If the circuit of the above

1)or 2) need to be used, do not turn off the prescaler. When operation of the prescaler is stopped, the clock

supply to the circuits of the above 2) stops. When some these circuits of the above 1) need to be used, turn off all other unnecessary circuits and stop the clock supply from the prescaler to those circuits.

The prescaler operating control and the clock supply control bits for each peripheral circuit are shown in the table below.

Function

Control bit

"1"

"0"

Default

Prescaler ON/OFF

PSCON(D5)/Power control register(0x40180)

ON

OFF

ON

16-bit timer 0 clock control

P16TON0(D3)/16-bit timer 0 clock control register(0x40147)

ON

OFF

OFF

16-bit timer 0 Run/Stop

PRUN0(D0)/16-bit timer 0 control register(0x48186)

RUN

STOP

STOP

16-bit timer 1 clock control

P16TON1(D3)/16-bit timer 1 clock control register(0x40148)

ON

OFF

OFF

16-bit timer 1 Run/Stop

PRUN1(D0)/16-bit timer 1 control register(0x4818E)

RUN

STOP

STOP

16-bit timer 2 clock control

P16TON2(D3)/16-bit timer 2 clock control register(0x40149)

ON

OFF

OFF

16-bit timer 2 Run/Stop

PRUN2(D0)/16-bit timer 2 control register(0x48196)

RUN

STOP

STOP

16-bit timer 3 clock control

P16TON3(D3)/16-bit timer 3 clock control register(0x4014A)

ON

OFF

OFF

16-bit timer 3 Run/Stop

PRUN3(D0)/16-bit timer 3 control register(0x4819E)

RUN

STOP

STOP

16-bit timer 4 clock control

P16TON4(D3)/16-bit timer 4 clock control register(0x4014B)

ON

OFF

OFF

16-bit timer 4 Run/Stop

PRUN4(D0)/16-bit timer 4 control register(0x481A6)

RUN

STOP

STOP

16-bit timer 5 clock control

P16TON5(D3)/16-bit timer 5 clock control register(0x4014C)

ON

OFF

OFF

16-bit timer 5 Run/Stop

PRUN5(D0)/16-bit timer 5 control register(0x481AE)

RUN

STOP

STOP

8-bit timer 0 clock control

P8TON0(D3)/8-bit timer 0/1 clock control register(0x4014D)

ON

OFF

OFF

8-bit timer 0 Run/Stop

PTRUN0(D0)/8-bit timer 0 control register(0x40160)

RUN

STOP

STOP

8-bit timer 1 clock control

P8TON1(D7)/8-bit timer 0/1 clock control register(0x4014D)

ON

OFF

OFF

8-bit timer 1 Run/Stop

PTRUN1(D0)/8-bit timer 1 control register(0x40164)

RUN

STOP

STOP

8-bit timer 2 clock control

P8TON2(D3)/8-bit timer 2/3 clock control register(0x4014E)

ON

OFF

OFF

8-bit timer 2 Run/Stop

PTRUN2(D0)/8-bit timer 2 control register(0x40168)

RUN

STOP

STOP

8-bit timer 3 clock control

P8TON3(D7)/8-bit timer 2/3 clock control register(0x4014E)

ON

OFF

OFF

8-bit timer 3 Run/Stop

PTRUN3(D0)/8-bit timer 3 control register(0x4016C)

RUN

STOP

STOP

8-bit timer 4 clock control

P8TON4(D3)/8-bit timer 4/5 clock control register(0x40145)

ON

OFF

OFF

8-bit timer 4 Run/Stop

PTRUN4(D0)/8-bit timer 4 control register(0x40174)

RUN

STOP

STOP

8-bit timer 5 clock control

P8TON5(D7)/8-bit timer 4/5 clock control register(0x40145)

ON

OFF

OFF

8-bit timer 5 Run/Stop

PTRUN5(D0)/8-bit timer 5 control register(0x40178)

RUN

STOP

STOP

A/D converter clock control

PSONAD(D3)/A/D clock control register(0x4014F)

ON

OFF

OFF

A/D conversion enable

ADE(D2)/A/D enable register(0x40244)

RUN

STOP

STOP

A-66

EPSON

S1C33L03 PRODUCT PART