AN3117

DMA programming examples

Doc ID 16846 Rev 4

19/28

4.2

Peripheral to memory transfer example 1: transferring data



from the ADC to the RAM via multi channel acquisitions

This example uses the ADC peripheral to convert two ADC input voltage channels in scan

mode using DMA.

Figure 4.

Transferring data from the ADC to the RAM via multi channel acquisition

The DMA event is provided by the ADC_EOC event. Each time the ADC completes the

conversion of the first input channel, it sends the end of conversion request to the DMA. As

soon as the DMA receives the request, it transfers the ADC data register value to the RAM

buffer (position 01). During this time, the ADC completes the conversion of the second input

channel and sends another end of conversion request to DMA. This request enables the

transfer of the ADC data register values to the RAM buffer (position 02).

Since the ADC is configured in continuous mode and the DMA is configured in circular

mode, ADC acquisition and transfer to the RAM are repeated indefinitely.

The code for this example is provided in the STM8L05x/STM8L15x/STM8L16x/STM8AL31x/

STM8AL3Lx standard peripheral library package.

ADC

DMA1

Data 01 L

Data 02 H

ADC_DRH

Data 02 L

DMA

destination

ADC AIN_3

System

bus

RAM bus

DMA

source

ADC_DRL

Data 01 H

DMA1 bus

ADC AIN_24

ai17419b

Channel 0