dc32-flames-addon/firmware/user/src/adc.c

/*
 * Created on: Jul 29, 2024
 *
 * not sure how well the ambient light sensor will work, being surrounded by other LEDs.
 * I guess I could make the programs black out and read then. maybe I'll do that.
 */

#include <ch32v20x.h>

#include "adc.h"


static const uint8_t led_brightness_map[] = {
    63, 60, 53, 48,
    47, 46, 45, 43,
    42, 41, 40, 39,
    38, 36, 35, 34,
    33, 31, 30, 28,     // indoors normal brightness
    26, 24, 22, 21,
    20, 20, 19, 19,
    18, 18, 17, 17
};



static GPIO_InitTypeDef lsens_a = {
        .GPIO_Mode = GPIO_Mode_Out_PP,
        .GPIO_Pin = LSENS_A_PIN,
        .GPIO_Speed = GPIO_Speed_2MHz
};
static GPIO_InitTypeDef lsens_k = {
        .GPIO_Mode = GPIO_Mode_Out_PP,
        .GPIO_Pin = LSENS_K_PIN,
        .GPIO_Speed = GPIO_Speed_2MHz
};

volatile uint16_t lsens_limits[2] = {LSENS_COARSE_UP, LSENS_COARSE_DOWN};

static uint8_t lsens_mode = LSENS_READING_IDLE;

uint16_t lsens_val;

uint8_t lsens_wait;
uint8_t lsens_coarse = 1;



void adc_init()
{
    ADC_InitTypeDef  adc = {0};

    RCC_ADCCLKConfig(RCC_PCLK2_Div4);

    ADC_DeInit(ADC1);
    adc.ADC_Mode = ADC_Mode_Independent;
    adc.ADC_ScanConvMode = DISABLE;
    adc.ADC_ContinuousConvMode = DISABLE;
    adc.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
    adc.ADC_DataAlign = ADC_DataAlign_Right;
    adc.ADC_NbrOfChannel = 1;
    ADC_Init(ADC1, &adc);

    ADC_RegularChannelConfig(ADC1, LSENS_ADC_CH, 1, ADC_SampleTime_239Cycles5);
    ADC_Cmd(ADC1, ENABLE);
}

void adc_convert()
{
    ADC_SoftwareStartConvCmd(ADC1, ENABLE);
}

void adc_read()
{
    uint16_t timeout = 0xfff;
    while((!ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC)) && timeout) timeout--;
    if (timeout) {
        lsens_val = ADC_GetConversionValue(ADC1);
    }
}

void adc_set_mode_lsens(uint8_t mode)
{
    lsens_mode = mode;

    if (mode == LSENS_OUTPUT) {
        lsens_a.GPIO_Mode = GPIO_Mode_Out_PP;
        lsens_k.GPIO_Mode = GPIO_Mode_Out_PP;
        GPIO_Init(LSENS_A_PORT, &lsens_a);
        GPIO_Init(LSENS_K_PORT, &lsens_k);
    }
}

uint8_t adc_get_mode_lsens()
{
    return lsens_mode;
}

static void lsens_start()
{
    // set anode and cathode low
    LSENS_A_PORT->BCR = LSENS_A_PIN;
    LSENS_K_PORT->BCR = LSENS_K_PIN;

    adc_set_mode_lsens(LSENS_READING_START);

    // set cathode high, let it charge
    LSENS_K_PORT->BSHR = LSENS_K_PIN;

    __asm("nop"); __asm("nop");
    __asm("nop"); __asm("nop");

    // set cathode as analog input
    lsens_k.GPIO_Mode = GPIO_Mode_AIN;
    GPIO_Init(LSENS_K_PORT, &lsens_k);
}

static void lsens_stop()
{
    lsens_a.GPIO_Mode = GPIO_Mode_Out_PP;
    lsens_k.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_Init(LSENS_A_PORT, &lsens_a);
    GPIO_Init(LSENS_K_PORT, &lsens_k);

    lsens_mode = LSENS_READING_IDLE;
}

void adc_process_lsens()
{
    if (lsens_mode != LSENS_OUTPUT) {
        // do what needs to be done by me to defeat the light enemys
        switch (lsens_mode) {
            case LSENS_READING_IDLE: {
                // prepare LED, wait a little bit
                lsens_start();
                adc_convert();
                lsens_wait = lsens_coarse;

                lsens_mode = LSENS_READING_START;

                break;
            }
            case LSENS_READING_START: {
                if (!lsens_wait) {
                    // convert the LED
                    adc_convert();

                    lsens_mode = LSENS_READING_WAIT;
                }

                lsens_wait--;

                break;
            }
            case LSENS_READING_WAIT: {
                // read the light sensor value
                adc_read();
                lsens_stop();

                // calculate adjustments
                if (lsens_val > lsens_limits[0]) {
                    lsens_coarse++;
                    if (lsens_coarse > 0x3f) lsens_coarse = 0x3f;
                } else if (lsens_val < lsens_limits[1]) {
                    if (lsens_coarse) lsens_coarse--;
                }

                lsens_wait = 255 - lsens_coarse;

                // wait a bit before doing it again
                lsens_mode = LSENS_READING_TIMEOUT;

                break;
            }
            case LSENS_READING_TIMEOUT: {
                if (!lsens_wait) {
                    // do it all again
                    lsens_mode = LSENS_READING_IDLE;
                }
                lsens_wait--;
            }
        }
    }
}

uint16_t adc_get_lsens()
{
    return lsens_val;
}

uint8_t adc_get_lsens_coarse()
{
    return lsens_coarse;
}

uint8_t adc_get_brightness(uint8_t level)
{
    if (!level) {
        // are you outside? why? it's too fucking hot
        // we'll shut down when in the presence of big nuclear fire
        if (adc_get_lsens() < 1800) {
            // yup, outside or in a spotlight at 3ft away or something
            return 0;
        }
    }

    if (level >= sizeof(led_brightness_map)) {
        return led_brightness_map[sizeof(led_brightness_map) - 1];

    }

    return led_brightness_map[level];
}