SN8P2604A
8-Bit Micro-Controller
5.3 WAKEUP
5.3.1 OVERVIEW
Under power down mode (sleep mode) or green mode, program doesn’t execute. The wakeup trigger can wake the
system up to normal mode or slow mode. The wakeup trigger sources are external trigger (P0, P1 level change) and
internal trigger (T0 timer overflow).
z
z
Power down mode is waked up to normal mode. The wakeup trigger is only external trigger (P0, P1 level change)
Green mode is waked up to last mode (normal mode or slow mode). The wakeup triggers are external trigger (P0,
P1 level change) and internal trigger (T0 timer overflow).
5.3.2 WAKEUP TIME
When the system is in power down mode (sleep mode), the high clock oscillator stops. When waked up from power
down mode, MCU waits for 2048 external high-speed oscillator clocks as the wakeup time to stable the oscillator circuit.
After the wakeup time, the system goes into the normal mode.
Note: Wakeup from green mode is no wakeup time because the clock doesn’t stop in green mode.
The value of the wakeup time is as the following.
The Wakeup time = 1/Fosc * 2048 (sec) + high clock start-up time
Note: The high clock start-up time is depended on the VDD and oscillator type of high clock.
Example: In power down mode (sleep mode), the system is waked up. After the wakeup time, the system goes
into normal mode. The wakeup time is as the following.
The wakeup time = 1/Fosc * 2048 = 0.512 ms (Fosc = 4MHz)
The total wakeup time = 0.512 ms + oscillator start-up time
5.3.3 P1W WAKEUP CONTROL REGISTER
Under power down mode (sleep mode) and green mode, the I/O ports with wakeup function are able to wake the
system up to normal mode. The Port 0 and Port 1 have wakeup function. Port 0 wakeup function always enables, but
the Port 1 is controlled by the P1W register.
0C0H
P1W
Read/Write
After reset
Bit 7
P17W
W
Bit 6
P16W
W
Bit 5
P15W
W
Bit 4
P14W
W
Bit 3
P13W
W
Bit 2
P12W
W
Bit 1
P11W
W
Bit 0
P10W
W
0
0
0
0
0
0
0
0
Bit[7:0]
P10W~P17W: Port 1 wakeup function control bits.
0 = Disable P1n wakeup function.
1 = Enable P1n wakeup function.
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