WROOM-32 + external SPI devices

techydude
Posts: 1
Joined: Wed May 02, 2018 12:37 am

WROOM-32 + external SPI devices

Postby techydude » Thu May 03, 2018 10:40 pm

Hi guys,
I'm finally trying to wrap my head around the ESP32, specifically with the ESP32-WROOM-32 module, as regards what I can use GPIO6..11 / WROOM-32 pins 17..22 for.

AFAIK these are connected to the 4Mbyte QSPI-Flash chip on the WROOM-32 module?
And those same 6 signals are brought out to the WROOM-32's external pins, but only for the purpose of connecting additional SPI-Flash or SPI-RAM *memory-mapped* devices?
And that those extra external SPI-Flash/SPI-RAM devices will need their own CSx pins, which can be mapped to any other GPIOx?
And I can't use those 6 WROOM-32 pins for general-purpose SPI devices?

My situation is that I'm intending to use a PaPiRus Eink display board (www.adafruit.com/product/3420) which has both the Eink display as one SPI device, as well as a 32Mbit SPI-Flash chip, sharing the same SPI bus with 2 CS signals. If I'm correct in my understanding above, I won't be able to use the QSPI signals for anything; I'll need to put the PaPiRus with its 2 SPI devices on a separate SPI bus (i.e. HSPI or VSPI) on other GPIO pins, right?

Thanks, Anthony.

ESP_Sprite
Posts: 8921
Joined: Thu Nov 26, 2015 4:08 am

Re: WROOM-32 + external SPI devices

Postby ESP_Sprite » Fri May 04, 2018 1:32 am

Yes. In theory it's possible to support other generic SPI devices over the flash SPI bus, but esp-idf does not have support for that yet.

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