GD32F20x User Manual
724
Figure 25-38. Process for power-down entry and exit
Command
Clock
(EXMC_SDCLK)
Clock Enable
(EXMC_SDCKE])
Active
NOP
Power-down Entry
Power-down Exit
Status and interrupt
The not ready status NRDY bit in EXMC_SDSTAT register specifies whether the SDRAM
controller is ready for a new command, this bit is cleared immediately after the command in
the SDRAMC’s internal register is sent.
Device0 and Device1 status bits STA0 and STA1 in EXMC_SDSTAT register defines the
status of SDRAM deivce0 and device1 respectively, 0b00 represents normal mode, 0b01
indicates that the corresponding SDRAM devices is in self-refresh mode, and 0b10 signifies
the power-down mode.
If a new refresh request occurs while the previous refresh command has not been served yet,
a refresh error flag (REIF) is raised in EXMC_SDSTAT register, and interrupt is generated if
REIE is set, refresh error flag is cleared by setting REC bit in EXMC_SDARI register.
Summary of Contents for GD32F20 Series
Page 191: ...GD32F20x User Manual 191 Bits Fields Descriptions 31 0 TRNDATA 31 0 32 Bit Random data ...
Page 290: ...GD32F20x User Manual 290 conversion is ongoing ...
Page 325: ...GD32F20x User Manual 325 15 0 ALRM 15 0 RTC alarm value low ...
Page 385: ...GD32F20x User Manual 385 ...
Page 523: ...GD32F20x User Manual 523 clears AERR bit by writing 0 to it ...