uPD789074 Subseries 8-Bit Single-Chip Microcontrollers UD - Home

CHAPTER 11 STANDBY FUNCTION(2) Releasing STOP modeSTOP mode can be released by the following two sources.(a) Releasing by unmasked interrupt requestSTOP mode can be released by an unmasked interrupt request. In this case, vectored interruptservicing is performed if interrupt acknowledgment is enabled after the oscillation stabilization time haselapsed. If interrupt acknowledgment is disabled, the instruction at the next address is executed.Figure 11-4. Releasing STOP Mode by InterruptSTOPinstructionWait(time set by OSTS)Standbyrelease signalOperatingmodeSTOP modeOscillation stabilizationwait statusOperatingmodeClockOscillationOscillationstopOscillationRemark The broken lines indicate the case where the interrupt request that has released standbymode is acknowledged.(b) Releasing by RESET inputWhen STOP mode is released by the RESET signal, the reset operation is performed after theoscillation stabilization time has elapsed.Figure 11-5. Releasing STOP Mode by RESET InputSTOPinstructionWait (2 15 /fX) NoteRESETsignalOperatingmodeSTOP modeResetperiodOscillationstabilizationwait statusOperatingmodeClockOscillationOscillationstopOscillationNote 3.28 ms (at fX = 10.0 MHz operation), 6.55 ms (at fX = 5.0 MHz operation)RemarkfX: System clock oscillation frequencyTable 11-4. Operation After Releasing STOP ModeReleasing Source MK×× IE OperationMaskable interrupt request0 0 Executes next address instruction.0 1 Executes interrupt servicing.1 × Retains STOP mode.RESET input − − Reset processing×: Don't care170User’s Manual U14801EJ3V1UD