EM78P458AP datasheet(27/76 Pages) EMC

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EM78P458/459

OTP ROM

(2) WDT time-out (if enabled).

(3) Port 6 input status change (if enabled).

(4) Comparator high.

(5) ADC complete.

The first two cases will cause the EM78P458/459 to reset. The T and P flags of R3 can be used to

determine the source of the reset (wake-up). Case 3 is considered the continuation of program

execution and the global interrupt ("ENI" or "DISI" being executed) decides whether or not the

controller branches to the interrupt vector following wake-up. If ENI is executed before SLEP, the

instruction will begin to execute from the address 0x8 after wake-up. If DISI is executed before SLEP,

the execution will restart from the instruction right next to SLEP after wake-up.

Only one of the Cases 2, to 4 can be enabled before entering into 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

EM78P458/459 can be awakened only by Case 1 or 3.

[b]

if WDT is enabled before SLEP, Port 6 Input Status Changed Interrupt must be disabled. Hence,

the EM78P458/459 can be awakened only by Case 1 or 2. Refer to the section on Interrupt for

further details.

[c]

if Comparator High Interrupt is enabled before SLEP, WDT must be disabled by software.

However, the WDT bit in the option register remains enabled. Hence, the EM78P458/459 can

be awakened only by Case 1 or 4.

If Port 6 Input Status Change Interrupt is used to wake up the EM78P458/459 (as in Case [a] above),

the following instructions must be executed before SLEP:

MOV A, @0Bxx000110

; Select internal TCC clock

CONTW

CLR R1

; Clear TCC and prescaler

MOV A, @0Bxxxx1110

; Select WDT prescaler

CONTW

WDTC

; Clear WDT and prescaler

MOV A, @0B0xxxxxxx

; Disable WDT

IOW RE

MOV R6, R6

; Read Port 6

MOV A, @0B00000x1x

; Enable Port 6 input change interrupt

IOW RF

This specification is subject to change without prior notice.

06.25.2004 (V1.4)

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