DMA works only when debugger is attached.

Michael Carrier

We have a project that is utilizing the C5534 DSP. We have 2 DMA channels configured one attached to an ADC, the other to move data from RAM to an EEPROM. With the debugger attached both DMA channels work correctly and the device functions as design. When I load the executable into and boot the device from EMMC the DMA hardware does not run. I have verifed that the ADC is generating interrupts as expected.

Is the GEL file doing something during init?

over 10 years ago

0 Steve Tsang over 10 years ago

TI__Mastermind 23785 points

Yes, The GEL does things. Please refer to this:
processors.wiki.ti.com/.../C5515_Boot-Image_Programmer
Regards.

0 Michael Carrier over 10 years ago in reply to Steve Tsang

Intellectual 370 points

Steve,
I do, in my user code, what your link suggests. I initial EVERYTHING in user code and do not rely on GEL as far as I can see. If I have the application running in CCS debugger, I click on the tools pulldown and the GEL files. There are no files listed which tells me that I am NOT relying on a GEL file.

All other peripherals (SPI, I2C, GPIOs) work as expected. DMA seems to be turned off or not being clocked. I was not sure if there is some other hidden trick CCS is doing during init relative to DMA.

any thoughts?

0 Steve Tsang over 10 years ago in reply to Michael Carrier

TI__Mastermind 23785 points

Thank you using on-line docuements so to cut down our workload. Yes, please check your PCGCR1 register, 0x1C02, bit 3 for DMA clock gating enable. GEL enables all. Also checks PCGCR2 for individual DMA's CG.
Regards.

0 Michael Carrier over 10 years ago in reply to Steve Tsang

Intellectual 370 points

Steve,

Here are my register settings PRCR = 0x0 PCGCR1 = 0x3ba1 PCGCR2 = 0x77. We use DMA 0 for EMMC writes and DMA 4. As can be seen the DMA clocks are enabled and the DMA device is not in reset. Not sure why the DMA hardware works with a debugger attached and does not work when the debugger is not attached.

0 Michael Carrier over 10 years ago in reply to Michael Carrier

Intellectual 370 points

Further comments is, if I bring our custom board up running code that is retrieved from the EMMC, the use Code Composer Studio, loading symbols only, to attach to the running code the DMA hardware magically works. Without that attachment the DMA hardware remains idle.

0 Vasantha K over 10 years ago in reply to Michael Carrier

TI__Genius 12575 points

Hi,

This seems to be event synchronization issues. When you run without the debugger somehow the events gets missed and it will get into idled, whereas when debugger is connected synchronization happens and everything becomes normal.

The reason for the above could be your software implementation. You may have to check and review your software code.

Refer to the below post. Similar issues were seen and resolved, though this is on a different C55xx device and with different peripheral.

http://e2e.ti.com/support/dsp/c5000/f/109/p/361235/1272382

Regards

Vasanth

0 Michael Carrier over 10 years ago in reply to Vasantha K

Intellectual 370 points

This seems highly unlikely as the events are coming from I2S2 towards the DMA1. These events are coming in 16000/second. The device is behaving as if DMA is not running at all.
Is there anyone on this thread I could speak with about this issue? The forum is nice but the turn around is very slow. This dead line for this project is coming quickly and I fear we are going to miss it.

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DMA works only when debugger is attached.