EM78P153EN EMC [ELAN Microelectronics Corp], EM78P153EN Datasheet - Page 18

• Manufacturer Part Number: EM78P153EN
• Description: EM78P153E is an 8-bit microprocessor with low-power and high-speed CMOS technology
• Manufacturer: EMC [ELAN Microelectronics Corp]

This specification is subject to change without prior notice.
The sleep (power down) mode is attained by executing the “SLEP” instruction. While entering sleep
mode, WDT (if enabled) is cleared but keeps on running. The controller can be awakened by
The first two cases will cause the EM78P153E to reset. The T and P flags of R3 can be used to
determine the source of the reset (wake-up). The last case is considered the continuation of program
execution and the global interrupt ("ENI" o r "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 008H after wake-up. If DISI is executed before
SLEP, the operation will restart from the 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 changed interrupt is enabled before SLEP , WDT must be disabled. by
software. However, the WDT bit in the option register remains enabled. Hence, the EM78P153E 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
EM78P153E 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 EM78P153E (Case [a] above), the
following instructions must be executed before SLEP:
One problem user should be aware of, is that after waking up from the sleep mode, WDT will enable
automatically. The WDT operation (being enabled or disabled) should be handled appropriately by
software after waking up from sleep mode.
(1) External reset input on /RESET pin,
(2) WDT time-out (if enabled), or
(3) Port 6 input status changes (if enabled).
MOV A, @xxxx1110b
CONTW
WDTC
MOV A, @0xxxxxxxb
IOW RE
MOV R6, R6
MOV A, @00000x1xb
IOW RF
ENI (or DISI)
SLEP
; Select WDT prescaler
; Clear WDT and prescaler
; Disable WDT
; Read Port 6
; Enable Port 6 input change interrupt
; Enable (or disable) global interrupt
; Sleep
18
EM78P153E
OTP ROM
2002/03/01