PIC24EP256 SPI Speed to slow

[stefan.erni]

Hi Ben

I have a board with an pic24ep256. It's working fine.
The delay time is exactly and the IRQ time is exactly.
The clock from the CPU is 80Mhz.
I use a software SPI with a divider Fosc/2
If I measure the clock is only 760kHz.
I need a 2.5Mhz clock.

How can I understand what FC is doing with this clock divider and how can I change it?

[LeighM]

Hi,
For the software SPI, the Prescale value determines the number of nop to use as a delay.
If you want to try a faster clock then you will need to edit PIC16BIT_CAL_SPI.c
Have a look at lines 324 and 351 where MX_PRESCALE_VAR_X is use as a Clock delay
As a suggestion, try removing the for loop, such that only one nop is used ...

Code: Select all

			//Clock delay
			// for (i=0; i<MX_PRESCALE_VAR_X; i++)
				nop();

[stefan.erni]

Hi Leigh

Thank you for the additional infos. I removed the "for loop" and it's 20% faster.