W_DMA.md

Minimal implementation of W80x DMA support

The W80x controllers has an eight equivalent DMA channels. Every channel can be used for every type of DMA transfers. This library is intended to help the user configure the DMA for some typical Memory-to-Periph or Periph-to-Memory application modes.

Usage

To add DMA functionality to your sketch you'll need a three simple steps.

1. Get number of next unused DMA channel.

dma_ch = claim_unused_dma_channel();

Returns channel number 0-7 or (-1) if no free channel available.

2. Configure the channel to work with selected peripheral.

DMA_HandleTypeDef* hdma = dma_simple_config(dma_ch, request_src);

Where dma_ch is channel number, obtained in step 1. Parameter request_src should be one of:

• DMA_REQUEST_SOURCE_SPI_RX
• DMA_REQUEST_SOURCE_SPI_TX
• DMA_REQUEST_SOURCE_ADC_CH0
• DMA_REQUEST_SOURCE_ADC_CH1
• DMA_REQUEST_SOURCE_ADC_CH2
• DMA_REQUEST_SOURCE_ADC_CH3
• DMA_REQUEST_SOURCE_I2S_RX
• DMA_REQUEST_SOURCE_I2S_TX
• DMA_REQUEST_SOURCE_SDIO_RX
• DMA_REQUEST_SOURCE_SDIO_TX

The method returns a pointer to preconfigured DMA handle.

3. Init the hardware with prepared configuration

result = dma_init(hdma);

The method returns HAL_OK if success or HAL_ERROR in case of any issue.

Congratulation! Now the DMA channel is configured and initialized, you can attach it to selected peripheral transfer.

Examples of using:

• Wav_SD_Player.ino
• Spi_tx_dma.ino