/*
 * Created on: Jul 29, 2024
 *
 * touch my pepper
 */

#include <stdint.h>
#include <ch32v20x.h>

#include "touch.h"



const uint16_t tbtn_adc_ch[2] = {TBTN2, TBTN1};
uint16_t tbtn_idle_cal[2];


uint16_t touch_read_adc(u8 adc_ch)
{
    ADC_RegularChannelConfig(TBTN_ADC, adc_ch, 1, ADC_SampleTime_7Cycles5);
    TBTN_ADC->IDATAR1 = 0x10;  // charging time
    TBTN_ADC->RDATAR  = 0x08;  // discharging time

    while(!ADC_GetFlagStatus(TBTN_ADC, ADC_FLAG_EOC));
    return (uint16_t)TBTN_ADC->RDATAR;
}

uint16_t touch_read(u8 btn_ch)
{
    if (btn_ch < 2) return touch_read_adc(tbtn_adc_ch[btn_ch]);
    else return 0xffff;
}

uint8_t touch_read_pushed(uint8_t btn_ch)
{
    if (touch_read_adc(tbtn_adc_ch[btn_ch]) < tbtn_idle_cal[btn_ch] - TBTN_PUSHED_COUNTS)
        return 1;

    return 0;
}

void touch_cal()
{
    uint8_t i, j;
    uint16_t val;

    for (i = 0; i < 2; i++) {
        val = 0xffff;
        while (val > TBTN_IDLE_WINDOW_HI) {
            // be warned,
            // we can hang here until the buttons can be calibrated
            val = touch_read(tbtn_adc_ch[i]);
        }

        // get average of 8 readings
        val = 0;
        for (j = 0; j < 8; j++) {
            val += touch_read(tbtn_adc_ch[i]);
        }
        val >>= 3;

        tbtn_idle_cal[i] = val;
    }
}

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

    // make sure ADC peripheral is clocked and
    // pins are configured as analog inputs before calling this function.

    // configure ADC for touchkey use
    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(TBTN_ADC, &adc);

    // enable ADC, then enable touchkey
    ADC_Cmd(TBTN_ADC, ENABLE);
    TBTN_ADC->CTLR1 |= ADC_CTLR1_BUFEN | ADC_CTLR1_TKENABLE;

    // calibrate idle touch
    touch_cal();
}