¡ Semiconductor
MSM80C48/49/50, MSM80C35/39/40
4.2 Cancellation of software power-down mode
The power-down mode status outlined above in examples 1 to 6 can be cancelled by using
either the interrupt pin or the RESET pin.
(1) Use of the INT pin during external interrupt enable mode (i.e. following execution of
EN I instruction).
m The clock generator is activated and the CPU is started up when a "0" level is
applied to the INT pin. If this "0" level is maintained until the occurrence of at least
2 ALE output signals, an external interrupt is generated, and execution proceeds
from address 3. If, however, the power-down is entered during the interrupt
processing routine, execution resumes just after the power-down instruction.
(2) Use of the INT pin during external interrupt disable mode (i.e. following execution of
DIS I instruction or hardware reset)
m The clock generator is activated and the CPU is started up when a "0" level is
applied to the INT pin. When "0" level is maintained until the occurrence of at least
2 ALE output signals, execution is resumed just after the power-down instruction.
(3) Use of the RESET pin
m The clock generator is activated and the CPU started up when a "0" level is applied
totheRESETpin. Ifthis"0"levelismaintaineduntiltheoccurrenceofatleast2ALE
output signals, the CPU is reset and execution proceeds from address 0. In case
cancellation is done in oscillation stop mode, the "0" level must be input to the
RESET pin until oscillation is stabilized.
17/20
OKI [ OKI ELECTRONIC COMPONETS ]
