DMA priority backwards?

[antonypace]

On a LPC4078 I'm using 2 channels of DMA to send and receive through a SPI connection (SSP peripheral) and have send on channel 0 and receive on channel 1. I start the DMA on channel 0 first. Channel 0 has higher priority than channel 1. Both send and receive are 14 bytes of data. 

I get channel 1 DMA complete interrupt first and I was xpecting to get channel 0 complete interrupt first.

It appears as though the send happens first and then the receive ie they are half duplex, which I am quite happy about.

Ant

[jeremyzhou]

Hi  Antony Pace,

Thank you for your interest in NXP Semiconductor products and 

for the opportunity to serve you.

To provide the fastest possible support, I've attached the demo and please refer to it for details.

Have a great day,
TIC

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[antonypace]

Hi,

Thank you for the reply. I've had a lookk at the demo code but I don't

see that it answers the question. Am I missing something?

Thanks

Ant

[jeremyzhou]

Hi Antony Pace,

Thanks for your reply.

The demo is used to demonstrate the SPI working with the DMA which just meets your requirement.

Have a great day,
TIC

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Note: If this post answers your question, please click the Correct Answer button. Thank you!
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