Re: Needed additional pins for PSRAM
Posted: Fri Jun 02, 2017 12:26 pm
@ESP_igrr:
With the two mentioned points (pin strapping/ eFuse Deep-Sleep problems) I mean based on the information in the Espressif documentation and the posts in the forum:
a.) Pin strapping: That the LDO of the ESP is configured with a VDD_SDIO = 3.3V till the eFuses are read (even if they are correctly programmed for 1.8V) when something with the external pull-up pin strapping at the MTDI pin goes wrong because the internal default is "pull-down" = 3.3V. This way round you can destroy an external 1.8V pSRAM.
b.) Deep-Sleep: You can benefit from the disabling of the VDD_SDIO disabling in Deep-Sleep via software. If you try to avoid a.) with an own external 1.8V supply for VDD_SDIO you have to find an own solution to disable the external supplied 1.8V VDD_SDIO in Deep-Sleep and reenable it on time when the ESP32 should leave Deep-Sleep to bring Iq down.
With the two mentioned points (pin strapping/ eFuse Deep-Sleep problems) I mean based on the information in the Espressif documentation and the posts in the forum:
a.) Pin strapping: That the LDO of the ESP is configured with a VDD_SDIO = 3.3V till the eFuses are read (even if they are correctly programmed for 1.8V) when something with the external pull-up pin strapping at the MTDI pin goes wrong because the internal default is "pull-down" = 3.3V. This way round you can destroy an external 1.8V pSRAM.
b.) Deep-Sleep: You can benefit from the disabling of the VDD_SDIO disabling in Deep-Sleep via software. If you try to avoid a.) with an own external 1.8V supply for VDD_SDIO you have to find an own solution to disable the external supplied 1.8V VDD_SDIO in Deep-Sleep and reenable it on time when the ESP32 should leave Deep-Sleep to bring Iq down.