Using multiple SPI devices with ESP32

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Joined: Tue Jul 16, 2019 2:19 pm

Using multiple SPI devices with ESP32

Postby sulli14 » Tue Jul 16, 2019 2:50 pm


I am developing a system using the ESP32-Wroom-32.
I will interface an ADS1299 (8channel ADC) chip and a microSD card with the ESP32.
My understanding is, the ESP32-Wroom-32 has 3 available SPI buses (SPI, HSPI, VSPI).

However, HSPI (pins: IO14, IO12, IO13, IO15) is used by JTAG debugger, which I need to use, so I can't use this for one of the peripherals I assume?

I plan to use VSPI (pins: IO18, IO19, IO23, IO5) for the ADC chip. Is that ok? The ADC chip will sample at 256Hz, and clock stability, etc is very important for this application. Will there be any issues with this?

That leaves the SPI (pins: CLK, SDO, SDI, CMD). Can I use the microSD card with this, or is it already used on-board for flash or something? I can't figure it out from the datasheet.

Finally, is there any other issues I'm overlooking that would make the ESP32 unsuitable for use with the ADC chip?

Thanks for your help.

Posts: 2956
Joined: Tue Dec 01, 2015 7:35 am

Re: Using multiple SPI devices with ESP32

Postby WiFive » Wed Jul 17, 2019 2:41 pm

Yes SPI is used for flash. HSPI can work on alternate pins like most digital peripherals via gpio matrix with only a few limitations.

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