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PostPosted: Tue Apr 18, 2017 1:05 pm 
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Joined: Thu Oct 29, 2015 10:25 am
Posts: 9
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:
File comment: MOD54415 DSPI channel 1 SCK and SOUT
DSPI_ch_1_SCK_SOUT.JPG
DSPI_ch_1_SCK_SOUT.JPG [ 50.45 KiB | Viewed 394 times ]
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PostPosted: Tue Apr 18, 2017 1:39 pm 

Joined: Thu Apr 24, 2008 3:58 pm
Posts: 701
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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PostPosted: Tue Apr 18, 2017 7:05 pm 
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Joined: Thu Oct 29, 2015 10:25 am
Posts: 9
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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PostPosted: Thu Apr 20, 2017 11:58 am 
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Joined: Mon Feb 06, 2012 10:37 am
Posts: 609
Location: San Diego, CA
Are you running the DSPI driver or a custom one? The DSPI driver sets the slew automatically based on configured clock speed...

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Dan Ciliske
Project Engineer
Netburner, Inc


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