HC32F4A0 development board DAC signal generation test

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HC32F4A0 development board DAC signal generation test

1 Overview

1.1 Development Board Interface

HC32F4A0 is equipped with two 12-bit digital-to-analog voltage converter units DAC1 and DAC2. Each DAC unit contains two D/A conversion channels, which can be converted independently or synchronously through synchronous update of conversion data. Each conversion channel is equipped with an output amplifier, which can directly drive external loads without external op amps. Independent pin input reference voltages VREFH and VREFL can be used to improve conversion accuracy.

Referring to the official routines, it is planned to generate four waveforms: sine wave, square wave, sawtooth wave, and triangle wave, and use buttons K1 ~ K5 to control the generation and closing of the waveform.

1.2 Development Board Schematic Diagram

The DAC peripheral circuit and pin assignment are shown in Figures 1 and 2.

Figure 1 DAC peripheral circuit diagram

Figure 2 Pin assignment diagram

1.3 Test Equipment

The equipment used in this test is shown in Table 1, and the physical equipment connection diagram is shown in Figure 3:

Test Equipment	unit	quantity
EV_F4A0_LQ176_REV1.0 development board	piece	one
ARM Emulator	indivual	one
5V power adapter	indivual	one
RIGOL DHO804 Oscilloscope	tower	one

Table 1 Test equipment

Figure 3 Development board physical connection diagram

2. Code Writing

Square wave generation function

static void Pulse_Init(uint32_t pPulseTable[], uint32_t u32count)
{
	uint32_t i;
    float32_t pulse;
    for (i = 0U; i < u32count; i++) {
        if(i<=u32count/2-1)
			pulse=u32count;
		else
			pulse=0;

#if (DAC_DATA_ALIGN == DAC_DATA_ALIGN_LEFT)
        {
            pPulseTable[i] = (uint32_t)pulse << 9;
        }
#else
        {
            pSinTable[i] = (uint32_t)fSin;
        }
#endif
    }
}

Sawtooth wave generation function

static void Sawtooth_Init(uint32_t pSawTable[], uint32_t u32count)
{
	uint32_t i;
    float32_t sawtooth;
    for (i = 0U; i < u32count; i++) {
        sawtooth=i;

#if (DAC_DATA_ALIGN == DAC_DATA_ALIGN_LEFT)
        {
            pSawTable[i] = (uint32_t)sawtooth << 9;
        }
#else
        {
            pSinTable[i] = (uint32_t)fSin;
        }
#endif
    }
}

Triangle wave generation function

static void Triangle_Init(uint32_t pTriangleTable[], uint32_t u32count)
{
	uint32_t i;
	uint32_t j=0;
    float32_t triangle;
    for (i = 0U; i < u32count; i++) {
        if(i<=u32count/2-1)
			j=j+1;
			
		else
			j=j-1;
		
	triangle=j;

#if (DAC_DATA_ALIGN == DAC_DATA_ALIGN_LEFT)
        {
            pTriangleTable[i] = (uint32_t)triangle*2 << 9;
        }
#else
        {
            pSinTable[i] = (uint32_t)fSin;
        }
#endif
    }
}

Main function

int32_t main(void)
{
    uint16_t u16OutputCnt = 0U;
    en_key_event_t enEvent;
    uint8_t u8IsConversionStart = 0U;
	uint32_t flag=0U;

    LL_PERIPH_WE(LL_PERIPH_GPIO | LL_PERIPH_FCG | LL_PERIPH_PWC_CLK_RMU | \
                 LL_PERIPH_EFM | LL_PERIPH_SRAM);

    BSP_CLK_Init();
    BSP_IO_Init();
    BSP_LED_Init();
    BSP_KEY_Init();

    /* Init MAU for generating sine data*/
    MAU_Init();
    /* Init sine data table */
    static uint32_t gu32SinTable[SINE_DOT_NUMBER];
    SinTable_Init(gu32SinTable, SINE_DOT_NUMBER);
	
	static uint32_t gu32SawTable[SINE_DOT_NUMBER];
    Sawtooth_Init(gu32SawTable, SINE_DOT_NUMBER);
	
	static uint32_t gu32PulseTable[SINE_DOT_NUMBER];
    Pulse_Init(gu32PulseTable, SINE_DOT_NUMBER);
	
	static uint32_t gu32TriangleTable[SINE_DOT_NUMBER];
    Triangle_Init(gu32TriangleTable, SINE_DOT_NUMBER);
	
	DAC_ConversionInit();
	
    LL_PERIPH_WP(LL_PERIPH_GPIO | LL_PERIPH_FCG | LL_PERIPH_PWC_CLK_RMU | \
                 LL_PERIPH_EFM | LL_PERIPH_SRAM);

    for (;;) {
        enEvent = Key_Event();
        switch (enEvent) {
            case E_KEY1_PRESSED:
                if (u8IsConversionStart == 1U) {
                    break;
                }
				flag=1;
                u16OutputCnt = 0U;
                u8IsConversionStart = 1U;
                BSP_LED_On(LED_BLUE);
                DAC_StartConversion();
                break;
			case E_KEY2_PRESSED:
                if (u8IsConversionStart == 1U) {
                    break;
                }
				flag=2;
                u16OutputCnt = 0U;
                u8IsConversionStart = 1U;
                BSP_LED_On(LED_BLUE);
                DAC_StartConversion();
                break;
			case E_KEY3_PRESSED:
                if (u8IsConversionStart == 1U) {
                    break;
                }
				flag=3;
                u16OutputCnt = 0U;
                u8IsConversionStart = 1U;
                BSP_LED_On(LED_BLUE);
                DAC_StartConversion();
                break;
			case E_KEY4_PRESSED:
                if (u8IsConversionStart == 1U) {
                    break;
                }
				flag=4;
                u16OutputCnt = 0U;
                u8IsConversionStart = 1U;
                BSP_LED_On(LED_BLUE);
                DAC_StartConversion();
                break;
            case E_KEY5_PRESSED:
                if (u8IsConversionStart == 0U) {
                    break;
                }
                u8IsConversionStart = 0U;
                DAC_StopConversion();
                BSP_LED_Off(LED_BLUE);
                break;

            default:
                break;
        }

        if (u8IsConversionStart == 0U) {
            continue;
        }
		if (flag==1){
			DAC_SetConversionData(gu32SinTable[u16OutputCnt]);
		}
        else if(flag==2){
			DAC_SetConversionData(gu32SawTable[u16OutputCnt]);
		}
		else if(flag==3){
			DAC_SetConversionData(gu32PulseTable[u16OutputCnt]);
		}
		else if(flag==4){
			DAC_SetConversionData(gu32TriangleTable[u16OutputCnt]);
		}
		else{
		}
        /* Loop output */
        if (++u16OutputCnt >= SINE_DOT_NUMBER) {
            u16OutputCnt = 0U;
        }
    }
}

3 Experimental Phenomena

3.1 Experimental Phenomenon Analysis

Press K1, K2, K3, and K4 on the development board, and the oscilloscope will display sine wave, sawtooth wave, square wave, and triangle wave respectively. Pressing K5 will turn off the DAC output.

3.2 Experimental Phenomena

As shown in Figures 4, 5, 6, and 7

Figure 4 Sine wave

Figure 5 Sawtooth wave

Figure 6 Square wave

Figure 7 Triangle wave