Elan EM78P156EL Manual page 20

controller branches to the interrupt vector following wake-up. If ENI is executed before SLEP, the
instruction will begin to execute from the address 008H after wake-up. If DISI is executed before
SLEP, the operation will restart from the succeeding instruction right next to SLEP after wake-up.
Only one of Cases 2 and 3 can be enabled before entering the sleep mode. That is,
[a] if Port 6 Input Status Change Interrupt is enabled before SLEP , WDT must be disabled. by
software. However, the WDT bit in the option register remains enabled. Hence, the
EM78P156EL can be awakened only by Case 1 or 3.
[b] if WDT is enabled before SLEP, Port 6 Input Status Change Interrupt must be disabled. Hence,
the EM78P156EL can be awakened only by Case 1 or 2. Refer to the section on Interrupt.
If Port 6 Input Status Change Interrupt is used to wake-up the EM78P156EL (Case [a] above), the
following instructions must be executed before SLEP:
MOV A, @xx000110b
CONTW
CLR R1
MOV A, @xxxx1110b
CONTW
WDTC
MOV A, @0xxxxxxxb
IOW RE
MOV R6, R6
MOV A, @00000x1xb
IOW RF
ENI (or DISI)
SLEP
NOP
One problem user should be aware of, is that after waking up from the sleep mode, WDT would
enable automatically. The WDT operation (being enabled or disabled) should be handled
appropriately by software after waking up from the sleep mode.
This specification is subject to change without prior notice.
; Select internal TCC clock
; Clear TCC and prescaler
; Select WDT prescaler
; Clear WDT and prescaler
; Disable WDT
; Read Port 6
; Enable Port 6 input change interrupt
; Enable (or disable) global interrupt
; Sleep
20
EM78P156EL
OTP ROM
2002/04/19