Use case: Single channel DAC transfer using DMA

This use case demonstrates how to transfer samples to a DAC channel using DMA.

Sequence diagram

Single channel DAC transfer using DMA

@startuml participant "Application" as App participant "DAC" as DAC participant "DMA driver" as dma participant "DMA IRQ handler" as isr participant "DMA Hardware" as Dmahard App -> DAC: HAL_DAC_ConfigChannel() App -> DAC: HAL_DAC_SetValue() App -> DAC: HAL_DAC_Start_DMA() DAC -> dma : HAL_DMA_Start_IT() isr -> dma : IRQ_HANDLER() Dmahard -> isr : DMA Hardware interrupt() dma -> DAC : DAC_DMAHalfConvCpltCh1() dma -> DAC : DAC_DMAConvCpltCh1() DAC -> App : APP callback over: weak HAL_DAC_ConvCpltCallback() App -> DAC: HAL_DAC_Stop_DMA() DAC -> dma: HAL_DMA_Abort() @enduml

Code snippet

HAL1

HAL2 

uint32_t aEscalator12bit[6] = {0x0, 0x330, 0x660, 0x990, 0xCC0, 0xFF0};
DAC_ChannelConfTypeDef sConfig;
sConfig.DAC_HighFrequency = DAC_HIGH_FREQUENCY_INTERFACE_MODE_ABOVE_80MH;
sConfig.DAC_DMADoubleDataMode = DISABLE;
sConfig.DAC_SignedFormat = DISABLE;
sConfig.DAC_SampleAndHold = DAC_SAMPLEANDHOLD_DISABLE;
sConfig.DAC_Trigger = DAC_TRIGGER_SOFTWARE;
sConfig.DAC_OutputBuffer = DAC_OUTPUTBUFFER_ENABLE;
sConfig.DAC_ConnectOnChipPeripheral = DAC_CHIPCONNECT_EXTERNAL;
sConfig.DAC_UserTrimming = DAC_TRIMMING_FACTORY;
sConfig.DAC_TrimmingValue = 31;
HAL_DAC_ConfigChannel(&hdac1, &sConfig, DAC_CHANNEL_1);

HAL_DAC_SetValue(&hdac1, DAC_CHANNEL_1, DAC_ALIGN_12B_R, 2048);

HAL_DAC_Start_DMA(&hdac1, DAC_CHANNEL_1, aEscalator12bit, 6, DAC_ALIGN_12B_R);

HAL_DAC_Stop_DMA(&hdac1, DAC_CHANNEL_1);

uint32_t aEscalator12bit[6] = {0x0, 0x330, 0x660, 0x990, 0xCC0, 0xFF0};
hal_dac_config_t p_config;
hal_dac_channel_config_t p_config1;

p_config.high_frequency_mode = HAL_DAC_HIGH_FREQ_MODE_ABOVE_80MHZ;
HAL_DAC_SetConfig(&hdac, &p_config);

p_config1.data_sign_format = HAL_DAC_SIGN_FORMAT_UNSIGNED;
p_config1.data_trigger = HAL_DAC_TRIGGER_TIM1_TRGO;
p_config1.output_buffer = HAL_DAC_OUTPUT_BUFFER_ENABLED;
p_config1.output_connection = HAL_DAC_OUTPUT_CONNECTION_EXTERNAL;
p_config1.alignment = HAL_DAC_DATA_ALIGN_12_BITS_RIGHT;
HAL_DAC_SetConfigChannel(&hdac, HAL_DAC_CHANNEL_1,
                         &p_config1);

HAL_DAC_SetChannelAlignment(&hdac, HAL_DAC_CHANNEL_1,
                            HAL_DAC_DATA_ALIGN_12_BITS_RIGHT);
HAL_DAC_SetChannelData(&hdac, HAL_DAC_CHANNEL_1,
                       2048);

HAL_DAC_StartChannel_DMA(&hdac, HAL_DAC_CHANNEL_1, aEscalator12bit, 6);

HAL_DAC_StopChannel_DMA(&hdac, HAL_DAC_CHANNEL_1);

Key changes

  1. In HAL2, channel configuration and data setting are performed using channel-based APIs.

  2. In HAL2, DMA transfer start/stop operations are performed per channel using HAL_DAC_StartChannel_DMA() and HAL_DAC_StopChannel_DMA().