Update PWM duty cycle with DMA

antoniomagrì — Wed, 12 Nov 2014 13:03:39 GMT

Hello everyone,

I am new to Kinetis microcontrollers and Kinetis SDK development, I own a TWR-KV31120M board and I am trying to set a project up in KDS using SDK and PE.

I was able to create a PWM output and change its duty cycle in software, but I am now trying to update the value from RAM using DMA.

I created and configured a fsl_edma component:

This led to the generation of initialization code for DMA, which initializes DMA, requests a channel, and installs a callback function.

If I understand correctly now it's up to me to configure the loop with EDMA_DRV_ConfigLoopTransfer and start it with EDMA_DRV_StartChannel.

I am trying to have the content of a 16-bit variable, pwmduty, to the TPM0_C0V register (also 16-bit).

This is the way I am doing the calls to the functions:

if (EDMA_DRV_ConfigLoopTransfer(&dmaController1_ChnState0,&descriptor,

kEDMAMemoryToPeripheral,

(uint32_t)&pwm_duty,

(uint32_t)&FTM0_C0V,

) == kStatus_EDMA_Success) {

EDMA_DRV_StartChannel(&dmaController1_ChnState0);

}

While the code above is executed (and the first call returns success) I placed a breakpoint on the callback function and never see it called in debug...

Do you know what am I doing wrong?

Thank you very much for any suggestion you may have.

Best regards,

Antonio

Re: Update PWM duty cycle with DMA

adriancano — Wed, 17 Dec 2014 01:07:11 GMT

Hi,

Are you are adding the <driver_name>_irq.c file to your project? Please refer to this document in the section Troubleshooting: I’m trying to use a driver and keep falling into the default ISR

Hope this information can help you.

Best Regards,
Adrian Sanchez Cano
Technical Support Engineer
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Kinetis Software Development KitのトピックUpdate PWM duty cycle with DMA

Update PWM duty cycle with DMA

Re: Update PWM duty cycle with DMA