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MOD54415 DSPI Ch 1 SOUT slew rate

Posted: Tue Apr 18, 2017 1:05 pm
by mike
Regarding DSPI channel 1, SOUT (serial out).

Is there a way to speed up the slew rate of the SOUT (serial data out) signal ??
I can't find anything in the MCF5441x manual about how to increase the slew rate (faster rise and fall times) for channel 1.
With the existing slew rate, see attached scope shot, the channel 1 clock (data) rate is limited to approx. 3.9 MHz.
I have it set up to sample on rising clock edge.

I hope I'm missing something, I'd like to run the channel faster.

Re: MOD54415 DSPI Ch 1 SOUT slew rate

Posted: Tue Apr 18, 2017 1:39 pm
by pbreed
Look at section 15.3.8 of the MCF54415RM.pdf.

In nburn/docs/freescalemanuals/


I believe that

#include <sim.h>
sim1.gpio.srcr_sdhc=0xFF;

Will do what you want.

Re: MOD54415 DSPI Ch 1 SOUT slew rate

Posted: Tue Apr 18, 2017 7:05 pm
by mike
Great. Thank you. I didn't think to look at the 'other' pin function name register (duh). I'll try it right away.

Re: MOD54415 DSPI Ch 1 SOUT slew rate

Posted: Thu Apr 20, 2017 11:58 am
by dciliske
Are you running the DSPI driver or a custom one? The DSPI driver sets the slew automatically based on configured clock speed...