SuperH (SH) 64-Bit RISC Series SH-5 System Architecture, Volume ...

PRELIMINARY DATAPower management unit (PMU) 30710.4.10 Economy modeTransition to economy modeSetting any of the MSTP bits in the CRPC.MSTP to 1 causes the module to be put intoa low power state, this is normally achieved by disabling the clock supply to themodule but may use other mechanisms depending on the module. Use of thisfunction allows power consumption when the CPU is operating normally or in sleepmode to be further reduced.Note that to allow the integration of complex modules the powering down ofmodules is subject to confirmation in the MSTPACK. For example when poweringdown memory interfaces it may be necessary to power down all DMA’s first. Thepower down confirmation given by MSTPACK indicates to software when this hasbeen achieved and so enabling power down to be performed in a recoverable manner.Before using the MSTP bits to put a module into low power mode software shouldensure:1 The module is in suitable state for being stopped. This may involve configuringthe module into disabled state. Refer to individual module specification fordetails of how to do this.2 That the sequence in which modules are powered down is safe and does not leadto deadlock or loss of state. For example, DMA channels should be stopped beforethe memory interfaces which they use are stopped.Exit from economy modeThe module standby function is exited by clearing all the MSTP bits to 0, or by apower-on or manual reset via the NOT_RESETP or NOT_RESETM pins or either resetcaused by watchdog timer overflow.10.4.11 STATUS pin change timingThe STATUS1 and STATUS0 pin change timing is shown below.D R A FTThe meaning of the STATUS pin settings is as follows:Reset:Sleep:HH (STATUS1 high, STATUS0 high)HL (STATUS1 high, STATUS0 low)Standby:Normal:LH (STATUS1 low, STATUS0 high)LL (STATUS1 low, STATUS0 low)05-SA-10001 v1.0SuperH, Inc.SH-5 System Architecture, Volume 1: System