/*!
    \file  main.c
    \brief ADC oversample and shift 
*/

/*
    Copyright (C) 2017 GigaDevice

    2017-06-06, V1.0.0, firmware for GD32F3x0
*/

#include "gd32f3x0.h"
#include "systick.h"
#include <stdio.h>
#include "main.h"
#include "gd32f3x0_eval.h"

#define BOARD_ADC_CHANNEL          ADC_CHANNEL_11
#define ADC_GPIO_PORT              GPIOC
#define ADC_GPIO_PIN               GPIO_PIN_1

uint16_t adc_value = 0;

void rcu_config(void);
void gpio_config(void);
void nvic_config(void);
void adc_config(void);

/*!
    \brief      main function
    \param[in]  none
    \param[out] none
    \retval     none
*/

int main(void)
{
    /* system clocks configuration */
    rcu_config();
    /* systick configuration */
    systick_config();  
    /* GPIO configuration */
    gpio_config();
    /* NVIC configuration */
    nvic_config();
    /* ADC configuration */
    adc_config();
    /* configures COM port */
    gd_eval_com_init(EVAL_COM1); 
  
    adc_software_trigger_enable(ADC_REGULAR_CHANNEL);

    while(1){
        adc_flag_clear(ADC_FLAG_EOC);
        while(SET != adc_flag_get(ADC_FLAG_EOC)){
        }
        
        adc_value = ADC_RDATA;
        printf("16 times sample, 4 bits shift: 0x%x\r\n", adc_value);
        delay_1ms(1000);
    }
}

/*!
    \brief      configure the different system clocks
    \param[in]  none
    \param[out] none
    \retval     none
*/
void rcu_config(void)
{
    /* enable GPIOC clock */
    rcu_periph_clock_enable(RCU_GPIOC);
    /* enable ADC clock */
    rcu_periph_clock_enable(RCU_ADC);
    /* config ADC clock */
    rcu_adc_clock_config(RCU_ADCCK_APB2_DIV6);
}

/*!
    \brief      configure the GPIO peripheral
    \param[in]  none
    \param[out] none
    \retval     none
*/
void gpio_config(void)
{
    /* config the GPIO as analog mode */
    gpio_mode_set(ADC_GPIO_PORT, GPIO_MODE_ANALOG, GPIO_PUPD_NONE, ADC_GPIO_PIN);
}

/*!
    \brief      configure interrupt priority
    \param[in]  none
    \param[out] none
    \retval     none
*/
void nvic_config(void)
{
    nvic_priority_group_set(NVIC_PRIGROUP_PRE2_SUB2);
    nvic_irq_enable(ADC_CMP_IRQn, 0, 0);
}

/*!
    \brief      configure the ADC peripheral
    \param[in]  none
    \param[out] none
    \retval     none
*/
void adc_config(void)
{
    /* ADC contineous function enable */
    adc_special_function_config(ADC_CONTINUOUS_MODE, ENABLE);  
    /* ADC trigger config */
    adc_external_trigger_source_config(ADC_REGULAR_CHANNEL, ADC_EXTTRIG_REGULAR_NONE); 
    /* ADC data alignment config */
    adc_data_alignment_config(ADC_DATAALIGN_RIGHT);
    /* ADC channel length config */
    adc_channel_length_config(ADC_REGULAR_CHANNEL, 1);
 
    /* ADC regular channel config */
    adc_regular_channel_config(0, BOARD_ADC_CHANNEL, ADC_SAMPLETIME_55POINT5);
    adc_external_trigger_config(ADC_REGULAR_CHANNEL, ENABLE);

    /* 16 times sample, 4 bits shift */
    adc_oversample_mode_config(ADC_OVERSAMPLING_ALL_CONVERT, ADC_OVERSAMPLING_SHIFT_4B, ADC_OVERSAMPLING_RATIO_MUL16);
    adc_oversample_mode_enable();
    
    /* enable ADC interface */
    adc_enable();
    delay_1ms(1);
    /* ADC calibration and reset calibration */
    adc_calibration_enable();
}

/* retarget the C library printf function to the USART */
int fputc(int ch, FILE *f)
{
    usart_data_transmit(EVAL_COM1, (uint8_t)ch);
    while(RESET == usart_flag_get(EVAL_COM1, USART_FLAG_TBE));

    return ch;
}
