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EM78P809N
8-Bit Microcontroller
28 •
Product Specification (V1.0) 07.26.2005
(This specification is subject to change without further notice)
Table 2. Mode Switching Control
Mode Switch Switch Method Note
Normal Æ Sleep Set SIS = 1, execute SLEP instruction
Sleep Æ Normal /SLEEP pin wake up
Normal Æ Idle Set SIS = 0, execute SLEP instruction
Idle Æ Normal Interrupt
Table 3. Operation Mode
Operation Mode Frequency CPU Code
On-chip
Peripherals
Reset Reset Reset
Normal Fosc
Idle
Turn on
Fosc
Signal
Clock
Sleep Turn off
Halt
Halt
In NORMAL mode, the CPU core and on-chip peripherals operate in oscillator
frequency.
In IDLE mode, the CPU core halts, but the on-chip peripheral and oscillator circuit
remain active. IDLE mode is released to NORMAL mode by any interrupt source. If the
ENI instruction is set, an interrupt will be serviced first followed by executing the next
instruction which is after the IDLE mode is released and the interrupt service is finished.
If the ENI instruction is not set, the next instruction will be executed which is after the
IDLE mode start instruction. IDLE mode can also be released by setting the /RESET
pin to low and executing a reset operation.
In SLEEP mode, the internal oscillator is turned off and all system operation is halted.
SLEEP mode is released by /SLEEP pin (level sensitive or edge sensitive can be set by
System Control Register (SCR) bit 0 (REM)). After a warm-up period, the next
instruction will be executed which is after the SLEEP mode start instruction. SLEEP
mode can also be released by setting the /RESET pin to low and executing a reset
operation. In level sensitive mode, the /SLEEP pin must be confirmed in low level
before entering SLEEP mode. In edge sensitive mode, SLEEP mode is started even
when the /SLEEP pin is in high level.
Table 4. Wake-up Methods
Wake-up Signal
SLEEP Mode
R5 (SIS) = 1+SLEP
Instruction
IDLE Mode
R5 (SIS)= 0 + SLEP
Instruction
NORMAL
Mode
R5 (SIS)=(*)
1. Individual interrupt source
in IMR1, IMR2
2. WDT interrupt request
3. /INT0
4. ENI instruction is not
executed
No effect
(**)
1. Wake-up
2. Jump to the next
instruction or enter
IDLE mode
No effect
(**)