Hi
I am working on driver for SPIS and would like to run higher than 8 MHz. We have been doing some tests and seems like it is possible to go e.g. 10 MHz.
Is the nrf51810_PS the Max is 8 MHz, but with the following note: "The actual maximum data rate depends on the master's CLK to MISO and MOSI setup and hold
timings.".
Question: Is 8 MHz absolute maximum or is there any way to go higher than this as it seems to work fine for 10 MHz SPI clock as well.
Hi Flemming,
We have tested it to understand that it will work with all four CPOL and CPHA modes when master clock in at 8MHz and the setup and hold times at these frequency of the clock sourced from master will be for sure within the working limits of the SPIS functionality. But we cannot predict if the setup and hold times will be within limits if the frequency goes up. So to be safe and predictable, we can document that until 8MHz SPIS can work. It can work if clocked at higher speed from master.
Also looking at this chart 
The minimal times for one clock cycles =
(Rise time + high time + fall time + low time) = 30ns + 30ns + 30ns + 30ns = 120ns which is a maximum of 8.33MHz.
If the rise and fall time of the source clock from SPI master is less than 30ns, then you can get higher speed from my above calculation.
