9.5 Memory Controller Power-DownThe SDRAM can be put into power-down mode to save power. This is executedby setting MEMSCTRL.PWDM = 1.The figure below illustrates the command sequence issued by the SDRAMcontroller to initiate, maintain, and exit power-down mode.Temporary exitfrom power-downfor refresh ormemory read/writeaccessExitpower-downReady for data transferMEMSCTRL.PWDM = 1Power-downMEMSCTRL.PWDM = 0MDCKE lowMDCKE highNOPNOPRefresh single roworexecute read/write accessMEMSREFR.TREFFigure 9-13 Power-down command sequenceThe Memory Controller can be set into power-down mode by settingMEMSCTRL.PWDM = 1.When in SDRAM power-down mode, the Memory Controller keeps switching thedevice back and forth between power-down and refresh mode. It remains inpower-down for a refresh period of time (defined by MEMSREFR.TREF), thencomes out of power-down and does a single-row refresh. Afterwards it again goesinto power-down mode.Chapter 9 External Memory Interface Controller312 Preliminary User's Manual S19203EE1V3UM00
