Speed issues with 56F8013

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Speed issues with 56F8013

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liquidsquid
Contributor II
Hi all,
    I finally have CodeWarrior up and running with my obscure printer port... I am evaluating the 56F8013EVM for a home project I hope to turn into a product, and I am seemingly having some difficulties getting any performace out of the core.
    I have set up a processor expert project only turing on the bare essentials; The Cpu where I have the PLL clock set at 32MHz and using the On-chip relaxation oscillator, and two of the LEDs since I am using the EVM board for this test.
    I then simply call LED1_Toggle() in the for(;:smileywink: block of code in the main User Modules secion and observe the output on the pin.
    I was hoping if the core was running at 32MHz to see an output between 4-8MHz, maybe faster. Instead I see an output of 1.6MHz on a bare bones project, and a whopping 276kHz with the A/D module turned on in continuous mode.

First off, with the JTAG cable attached, does it slow things down when running?

I get no PLL error interrupts, however when I poll the locked flag of the PLLSR, it always says unlocked, though I am unsure how this could pass the initialization stage if so as the CPU initialization wont exit unless a lock ocurs.

Currently this project is pretty darned slim, so I cannot imagine much being wrong at this point, other than the device's PLL not cooperating or ProcessorExpert generating a crummy piece of code someplace which causes the PLL to unlock.

Thanks for any insight if anyone has run into this one before.

And quickly: Can I expect to be able to get a 32kHz sample rate on two channels at once? Even better, can I expect 32kHz sample rate staggered on four? I have been unable to confirm this on the demo board thanks to this clocking issue. The datasheet says so.

-Mark
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533 次查看
liquidsquid
Contributor II
Ok, it was the debugger slowing things up. I was having trouble getting the pod to run stand-alone to see any signalling, but once I did, the device truly flies. More then enough HP for what I need.

Now on to the next thing:
Getting the Beans in CodeWarrior setup to create the 32kHz sampling rate all interrupt driven. I want to write my code as an event-driven interface. However I am really struggling with these timer modules and the PWM, which I cannot seem to get enabled to give me a pulse train on a single output. I have some things to try still, but this is tough to do between dinner, bath for Joe, and bed...

This is certainly not the HCS08, which I have a lot of experience on. (Using the BDM, that is why the speed confusion).

BTW is there a more active forum sponsored or otherwise for newb questions like this? This one seems pretty dead compared to the old Yahoo groups.

-Mark
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liquidsquid
Contributor II
Ok, turns out it runs at full speed even in debug. Some setting somewhere during the process of my testing prevented the PLL from coming up, among other things. I created a spanking-new project to test just the PWM, and it fired right up. Then I imported my older project's beans into it, and it ran fine.

Gotta love problems like that when you are firing up something for the first time.
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