EM78P156ELAS datasheet(21/55 Pages) EMC

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EM78P156EL

OTP ROM

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

; Select internal TCC clock

CONTW

CLR R1

; Clear TCC and prescaler

MOV A, @xxxx1110b

; Select WDT prescaler

CONTW

WDTC

; Clear WDT and prescaler

MOV A, @0xxxxxxxb

; Disable WDT

IOW RE

MOV R6, R6

; Read Port 6

MOV A, @00000x1xb

; Enable Port 6 input change interrupt

IOW RF

ENI (or DISI)

; Enable (or disable) global interrupt

SLEP

; Sleep

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.

07.29.2004 (V1.3)

EM78P156ELAS Datasheet(PDF) 21 Page - ELAN Microelectronics Corp