Embedded Lab

Regular Group Channels Discontinuous in Mode

This example is similar to the one I coded for injected group channels. It is somewhat an alternative of scan mode for regular group though technically they are not same. You can use this mode to monitor several ADC channels in a systematic order.

#include "ADC.h"

#include "GPIO.h"

sbit LCD_RS at GPIOB_ODR.B1;

sbit LCD_EN at GPIOB_ODR.B2;

sbit LCD_D4 at GPIOB_ODR.B12;

sbit LCD_D5 at GPIOB_ODR.B13;

sbit LCD_D6 at GPIOB_ODR.B14;

sbit LCD_D7 at GPIOB_ODR.B15;

unsigned char channel_no = 0;

unsigned int ch_data[3] = {0x0000, 0x0000, 0x0000};

void setup();

void GPIO_init();

void ADC_init();

void lcd_print(unsigned char x_pos, unsigned char y_pos, unsigned int value);

void ADC1_2_ISR() 

iv IVT_INT_ADC1_2 

ics ICS_AUTO 

{

    ADC2_SRbits.EOC = 0;

    ch_data[channel_no] = (ADC2_DR & 0x0FFF);

    channel_no++;

}

void main()

{

    unsigned char s = 0;

    setup();

    while(1)

    {

        bit_set(GPIOC_ODR, 13);

        set_ADC2_regular_conversions(enable);

        while(channel_no < 3);

        channel_no = 0;

        for(s = 0 ; s < 3; s++)

        {

            lcd_print(((s * 6) + 1), 2, ch_data[s]);

        }

        bit_clr(GPIOC_ODR, 13);

    };

}

void setup()

{

    GPIO_init();

    ADC_init();

    LCD_Init();

    LCD_Cmd(_LCD_CLEAR);

    LCD_Cmd(_LCD_CURSOR_OFF);

    lcd_out(1, 1, "CH02  CH00  CH01");

}

void GPIO_init()

{

     enable_GPIOA(enable);

     enable_GPIOB(enable);

     enable_GPIOC(enable);

     pin_configure_low(GPIOA_CRL, 0, (analog_input | input_mode));

     pin_configure_low(GPIOA_CRL, 1, (analog_input | input_mode));

     pin_configure_low(GPIOA_CRL, 2, (analog_input | input_mode));

     pin_configure_high(GPIOC_CRH, 13, (GPIO_PP_output | output_mode_low_speed));

}

void ADC_init()

{

     ADC2_Enable();

     clr_ADC2_settings();

     set_ADC_mode(independent_mode);

     set_ADC2_data_alignment(right_alignment);

     set_ADC2_scan_conversion_mode(disable);

     set_ADC2_continuous_conversion_mode(disable);

     set_ADC2_regular_number_of_conversions(3);

     set_ADC2_number_of_discontinuous_conversions(3);

     set_ADC2_sample_time(sample_time_41_5_cycles, 0);

     set_ADC2_sample_time(sample_time_13_5_cycles, 1);

     set_ADC2_sample_time(sample_time_28_5_cycles, 2);

     set_ADC2_regular_sequence(1, 0);

     set_ADC2_regular_sequence(2, 1);

     set_ADC2_regular_sequence(3, 2);

     set_ADC2_external_trigger_regular_conversion_edge(SWSTART_trigger);

     set_ADC2_discontinuous_conversion_mode_in_regular_mode(enable);

     set_ADC2_regular_end_of_conversion_interrupt(enable);

     NVIC_IntEnable(IVT_INT_ADC1_2);

     EnableInterrupts();

     ADC2_calibrate();

     start_ADC2();

}

void lcd_print(unsigned char x_pos, unsigned char y_pos, unsigned int value)

{

     unsigned char tmp = 0;

     tmp = (value / 1000);

     lcd_chr(y_pos, x_pos, (tmp + 48));

     tmp = ((value / 100) % 10);

     lcd_chr_cp((tmp + 48));

     tmp = ((value / 10) % 10);

     lcd_chr_cp((tmp + 48));

     tmp = (value % 10);

     lcd_chr_cp((tmp + 48));

}

Demo video link: https://www.youtube.com/watch?v=pz-y_W2Lxr8.

Dual Conversion Mode

One of the cool feature of STM32’s ADC is its ability to simultaneous convert two ADC channels. This ability is sometimes highly demanded in some applications. For example in an energy meter you’ll need to measure both voltage and current simultaneous if you want precision. Applications like such demand the use of dual ADC mode. Please note that this feature is available only in those STM32 micros that have at least two ADC units. Fortunately there are only a few STM32 micros that have only one ADC unit. ST provided several sub modes for dual ADC modes but none attracted me much because those seemed to my achievable using one ADC and some programming tricks. It’s just my instinct. I could be wrong. To use dual ADC mode, we need to configure two ADC units separately. They’ll have some common setups. The individual ADCs are configured as such that as if they are configured for single ADC operation. The common settings are just ADC mode of operation setting and interrupt configuration. The results of ADC conversions of both channels are stored in ADC1_DR register Please note that ST recommends that we set the DMA bit for ADC1 even if we don’t use the DMA block itself.

#include "ADC.h"

#include "GPIO.h"

sbit LCD_RS at GPIOB_ODR.B1;

sbit LCD_EN at GPIOB_ODR.B2;

sbit LCD_D4 at GPIOB_ODR.B12;

sbit LCD_D5 at GPIOB_ODR.B13;

sbit LCD_D6 at GPIOB_ODR.B14;

sbit LCD_D7 at GPIOB_ODR.B15;

register unsigned long adc_data = 0;

void setup();

void GPIO_init();

void ADC_init();

void setup_ADC1();

void setup_ADC2();

void setup_common_ADC_settings();

void lcd_print(unsigned char x_pos, unsigned char y_pos, unsigned int value);

void ADC1_2_ISR() 

iv IVT_INT_ADC1_2 

ics ICS_AUTO 

{

    ADC1_SRbits.EOC = 0;

    ADC2_SRbits.EOC = 0;

    adc_data = adc1_dr;

    bit_set(GPIOC_ODR, 13);

}

void main()

{

    unsigned int adc1_data = 0;

    unsigned int adc2_data = 0;

    setup();

    while(1)

    {

        set_ADC1_regular_conversions(enable);

        adc1_data = (adc_data & 0x00000FFF);

        adc2_data = ((adc_data & 0x0FFF0000) >> 16);

        lcd_print(1, 2, adc1_data);

        lcd_print(13, 2, adc2_data);

        bit_clr(GPIOC_ODR, 13);

        delay_ms(90);

    };

}

void setup()

{

    GPIO_init();

    ADC_init();

    LCD_Init();

    LCD_Cmd(_LCD_CLEAR);

    LCD_Cmd(_LCD_CURSOR_OFF);

    lcd_out(1, 1, "CH00        CH01");

}

void GPIO_init()

{

     enable_GPIOA(enable);

     enable_GPIOB(enable);

     enable_GPIOC(enable);

     pin_configure_low(GPIOA_CRL, 0, (analog_input | input_mode));

     pin_configure_low(GPIOA_CRL, 1, (analog_input | input_mode));

     pin_configure_high(GPIOC_CRH, 13, (GPIO_PP_output | output_mode_low_speed));

}

void ADC_init()

{

     setup_ADC1();

     setup_ADC2();

     setup_common_ADC_settings();

}

void setup_ADC1()

{

     ADC1_Enable();

     clr_ADC1_settings();

     set_ADC1_data_alignment(right_alignment);

     set_ADC1_scan_conversion_mode(disable);

     set_ADC1_continuous_conversion_mode(disable);

     set_ADC1_sample_time(sample_time_41_5_cycles, 0);

     set_ADC1_external_trigger_regular_conversion_edge(SWSTART_trigger);

     set_ADC1_regular_number_of_conversions(1);

     set_ADC1_regular_sequence(1, 0);

     set_ADC1_regular_end_of_conversion_interrupt(enable);

     ADC1_calibrate();

     start_ADC1();

}

void setup_ADC2()

{

     ADC2_Enable();

     clr_ADC2_settings();

     set_ADC2_data_alignment(right_alignment);

     set_ADC2_scan_conversion_mode(disable);

     set_ADC2_continuous_conversion_mode(disable);

     set_ADC2_sample_time(sample_time_41_5_cycles, 1);

     set_ADC2_external_trigger_regular_conversion_edge(SWSTART_trigger);

     set_ADC2_regular_number_of_conversions(1);

     set_ADC2_regular_sequence(1, 1);

     set_ADC2_regular_end_of_conversion_interrupt(enable);

     ADC2_calibrate();

     start_ADC2();                       

}

void setup_common_ADC_settings()

{

     set_ADC1_DMA(enable);

     set_ADC_mode(regular_simultaneous_mode_only);

     NVIC_IntEnable(IVT_INT_ADC1_2);

     EnableInterrupts();

}

void lcd_print(unsigned char x_pos, unsigned char y_pos, unsigned int value)

{

     unsigned char tmp = 0;

     tmp = (value / 1000);

     lcd_chr(y_pos, x_pos, (tmp + 48));

     tmp = ((value / 100) % 10);

     lcd_chr_cp((tmp + 48));

     tmp = ((value / 10) % 10);

     lcd_chr_cp((tmp + 48));

     tmp = (value % 10);

     lcd_chr_cp((tmp + 48));

}

Demo video link: https://www.youtube.com/watch?v=sSGJUkX-mSg.

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