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Using multiple SPI devices with ESP32

Posted: Tue Jul 16, 2019 2:50 pm
by sulli14
Hello,

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.
:D

Re: Using multiple SPI devices with ESP32

Posted: Wed Jul 17, 2019 2:41 pm
by WiFive
Yes SPI is used for flash. HSPI can work on alternate pins like most digital peripherals via gpio matrix with only a few limitations.