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STM32F7 USB Device HS DMA enabled

Question asked by Momchil Stanchev on Jun 12, 2017
Latest reply on May 24, 2018 by Dodotronic

I'm working on the audio example and I've made it work with Audio Class 2.0. Device enumerates and ISO packets are received.

However when I decided to enable DMA for better performance the TX line is not working. Device receives Setup packets, but cannot transmit.

 

In the generated from CubeMX code I saw the following:

// Be aware that enabling DMA mode will result in data being sent only by multiple of 4 packet sizes. This is due to the fact

// that USB DMA does not allow sending data from non word-aligned addresses.

 

Does somebody knows how "large" is one packet or where that is defined?

Anyone bumped into that problem?

 

Using: 

 - System Workbench for STM32

 - STM32Cube_FW_F7_V1.7.0

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