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LPC43xx DMA with SSP

Question asked by John DeMar on Nov 12, 2018
Latest reply on Dec 3, 2018 by Alice_Yang

I am using an LPCLink2 as a target board. I have successfully set up two DMA channels for Tx and Rx with the SSP peripheral configured for SPI. I can run this as a one shot and the data is sent and returned (to/from an ADC chip). I began with the lpcopen_3_02_lpcxpresso_link2_4370.zip example project periph_ssp. I am using MCUXPresso.

 

When I use a Pin Interrupt to respond to the ADC ready line to start the transfer, I cannot get the DMA to respond quickly. The interrupt is happening at 60KHz when I simply toggling a pin. But it is very asynchonous and <8KHz when I try to start a short DMA transfer (less than the 60KHz period).

 

Is there an example somewhat related to what I am trying to do?  I'm assuming there must be a fast way to start/stop the DMA after configuring it once at power up. 

 

  -John DeMar

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