Cyton SPI SCLK frequency

GEng · August 2020

Hello,

I'm trying to understand what is the SPI data rate between the PIC32 and the ADS1299 in the Cyton board. I know that the sample rate is 250SPS, but I would like to know what is the bit rate that one sample is transmited in the SPI bus. Can someone help me?

Thanks.

wjcroft · August 2020

Hi GEng,

Some related discussion here,

http://chipkit.net/forum/viewtopic.php?t=243
http://ww1.microchip.com/downloads/en/DeviceDoc/DS-61106F.pdf

William

wjcroft · August 2020

https://microchipdeveloper.com/32bit:mx-osc-config

wjcroft · August 2020

but I would like to know what is the bit rate that one sample is transmitted in the SPI bus.

SCLK is ONE bit time on the SPI bus.

wjcroft · August 2020

GEng, hi again.

OK, final post.

Thanks to Eva Esteban @evaesteban, here is the actual line in the source code,

https://github.com/OpenBCI/OpenBCI_Cyton_Library/blob/master/OpenBCI_32bit_Library.cpp#L1326

So SCLK is 4 MHz. Also, the external crystal / resonator is 8 MHz, so a divide by two factor is common to derive SCLK.

Regards, William

Cyton SPI SCLK frequency

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