MOD54415 DSPI Ch 1 SOUT slew rate

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mike
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Joined: Thu Oct 29, 2015 10:25 am

MOD54415 DSPI Ch 1 SOUT slew rate

Post 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.
Attachments
MOD54415 DSPI channel 1 SCK and SOUT
MOD54415 DSPI channel 1 SCK and SOUT
DSPI_ch_1_SCK_SOUT.JPG (50.45 KiB) Viewed 3294 times
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pbreed
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Re: MOD54415 DSPI Ch 1 SOUT slew rate

Post 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.
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mike
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Joined: Thu Oct 29, 2015 10:25 am

Re: MOD54415 DSPI Ch 1 SOUT slew rate

Post 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.
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dciliske
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Re: MOD54415 DSPI Ch 1 SOUT slew rate

Post by dciliske »

Are you running the DSPI driver or a custom one? The DSPI driver sets the slew automatically based on configured clock speed...
Dan Ciliske
Project Engineer
Netburner, Inc
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