Connecting External SPI Flash to ESPWROOM32E Module

FCT_IOT
Posts: 37
Joined: Fri Jan 26, 2018 11:15 am

Connecting External SPI Flash to ESPWROOM32E Module

Postby FCT_IOT » Wed Jul 21, 2021 11:00 am

Hi,

I am integrating ESPWROOM32E module with MCU through UART0. I am using U0 TX,RX,CTS, RTS. Since, I am using U0RTS, I will not be able to use the VSPI Interface lines.

If I want to use the HSPI interface lines, some of the pins are interfering with Boot strapping. For example: MTDO has an internal pullup which enables debug log printing over U0TXD. I would like to disable debug logs on U0TXD line. But MTDO Pin also acts as HSPICS0. Hence, I will not be able to connect a pull down to this line.

Can you suggest me a solution for interfacing the external SPI flash using HSPI interface lines (IO13,IO2,IO4,IO12, IO14, IO15) without affecting the Boot strapping.

Thanks

ESP_Sprite
Posts: 9014
Joined: Thu Nov 26, 2015 4:08 am

Re: Connecting External SPI Flash to ESPWROOM32E Module

Postby ESP_Sprite » Thu Jul 22, 2021 1:00 am

Why would you not be able to connect a pulldown to this pin? In SPI mode, it acts as an output and the signals from the pin should be easily able to overpower the pulldown.

(Also note you can use almost any pin for SPI and UART signals, although for SPI it has some effects on the maximum speed. The SPI driver ESP-IDF documentation has the details on that.)

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