D0WD D2WD WROOM-32 WROVER deep sleep SPI Flash pSRAM

[WiFive]

Okay, can i finally give the reason why we don't burn the efuse for 1.8V in D2WD. The reason is, if the VDD_SDIO is configured by efuse, it takes some time for the hardware to read efuse values at startup. If the strapping pin configures VDD_SDIO to be 3.3V, then during this time, VDD_SDIO will be 3.3V. As soon as efuse read is complete, the regulator will switch to 1.8V.

Ah that is interesting. So vdd_sdio is powered on before efuse is read. I guess if it wasn't then it would impact flash startup time. So this applies to WROVER as well?

[rudi ;-)]

[
Ah that is interesting. So vdd_sdio is powered on before efuse is read. I guess if it wasn't then it would impact flash startup time. So this applies to WROVER as well?

@ivan
thank you for the clarification - this is a "must2know" detail.

@WiFive
the procedure to start and read efuses / bootstrap pins i tink is the same - but not sure that this is so.

best wishes
rudi

[rudi ;-)]

from the readthedocs
the standing theme 1.8V from flash and psram speak detailed 1.8V:

_info_electrical_flash+SRAM.jpg (30.87 KiB) Viewed 4352 times

alternate: but we can use 3.3 flash and 3.3 pSRAM-32 too right?
it is not a must2take 1.8V doing, or? then there is no need to use bootstrap or efuse.

does this Interfering ULP or deep sleep?

best wishes
rudi



ESP-64 then support 64MBit pSRAM 3.3V - and 64MBit pSRAM 1.8V too ? )