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lvgl_esp32_drivers/lvgl_touch/adcraw.c

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/**
* @file ADCRAW.c
*/
#include "adcraw.h"
#include "esp_system.h"
#include "esp_log.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/gpio.h"
#include <stddef.h>
#if CONFIG_LV_TOUCH_CONTROLLER_ADCRAW
#define TAG "ADCRAW"
#define CALIBRATIONINSET 1 // range 0 <= CALIBRATIONINSET <= 40
#define SAMPLE_CALIBRATION_POINTS 4
// use this scale factor to avoid working in floating point numbers
#define TOUCHSCREEN_RESISTIVE_CALIBRATION_SCALE_FACTOR 8
#define SCALE_FACTOR (1 << TOUCHSCREEN_RESISTIVE_CALIBRATION_SCALE_FACTOR)
#define CAL_X_INSET (((GetMaxX() + 1) * (CALIBRATIONINSET >> 1)) / 100)
#define CAL_Y_INSET (((GetMaxY() + 1) * (CALIBRATIONINSET >> 1)) / 100)
#define NUMSAMPLES 8
static void ad_touch_handler(void *arg);
static const esp_timer_create_args_t periodic_timer_args = {
.callback = &ad_touch_handler,
};
static esp_timer_handle_t periodic_timer;
// Current ADC values for X and Y channels
int16_t adcX, adcY = 0;
int16_t temp_x, temp_y, temp_z1, temp_z2;
// coefficient values
int _trA, _trB, _trC, _trD;
int16_t xRawTouch[SAMPLE_CALIBRATION_POINTS];
int16_t yRawTouch[SAMPLE_CALIBRATION_POINTS];
TOUCH_STATES state;
const gpio_num_t yu = TOUCHSCREEN_RESISTIVE_PIN_YU;
const gpio_num_t xl = TOUCHSCREEN_RESISTIVE_PIN_XL;
const gpio_num_t yd = TOUCHSCREEN_RESISTIVE_PIN_YD;
const gpio_num_t xr = TOUCHSCREEN_RESISTIVE_PIN_XR;
static const int gpio_to_adc[] = {
GPIO_TO_ADC_ELEMENT(TOUCHSCREEN_RESISTIVE_PIN_YD),
GPIO_TO_ADC_ELEMENT(TOUCHSCREEN_RESISTIVE_PIN_XR)
};
static void TouchCalculateCalPoints(void)
{
int32_t trA, trB, trC, trD; // variables for the coefficients
int32_t trAhold, trBhold, trChold, trDhold;
int32_t test1, test2; // temp variables (must be signed type)
int16_t xPoint[SAMPLE_CALIBRATION_POINTS], yPoint[SAMPLE_CALIBRATION_POINTS];
yPoint[0] = yPoint[1] = CAL_Y_INSET;
yPoint[2] = yPoint[3] = (GetMaxY() - CAL_Y_INSET);
xPoint[0] = xPoint[3] = CAL_X_INSET;
xPoint[1] = xPoint[2] = (GetMaxX() - CAL_X_INSET);
// calculate points transfer function
// based on two simultaneous equations solve for the constants
// use sample points 1 and 4
// Dy1 = aTy1 + b; Dy4 = aTy4 + b
// Dx1 = cTx1 + d; Dy4 = aTy4 + b
test1 = (int32_t)yPoint[0] - (int32_t)yPoint[3];
test2 = (int32_t)yRawTouch[0] - (int32_t)yRawTouch[3];
trA = ((int32_t)((int32_t)test1 * SCALE_FACTOR) / test2);
trB = ((int32_t)((int32_t)yPoint[0] * SCALE_FACTOR) - (trA * (int32_t)yRawTouch[0]));
test1 = (int32_t)xPoint[0] - (int32_t)xPoint[2];
test2 = (int32_t)xRawTouch[0] - (int32_t)xRawTouch[2];
trC = ((int32_t)((int32_t)test1 * SCALE_FACTOR) / test2);
trD = ((int32_t)((int32_t)xPoint[0] * SCALE_FACTOR) - (trC * (int32_t)xRawTouch[0]));
trAhold = trA;
trBhold = trB;
trChold = trC;
trDhold = trD;
// use sample points 2 and 3
// Dy2 = aTy2 + b; Dy3 = aTy3 + b
// Dx2 = cTx2 + d; Dy3 = aTy3 + b
test1 = (int32_t)yPoint[1] - (int32_t)yPoint[2];
test2 = (int32_t)yRawTouch[1] - (int32_t)yRawTouch[2];
trA = ((int32_t)(test1 * SCALE_FACTOR) / test2);
trB = ((int32_t)((int32_t)yPoint[1] * SCALE_FACTOR) - (trA * (int32_t)yRawTouch[1]));
test1 = (int32_t)xPoint[1] - (int32_t)xPoint[3];
test2 = (int32_t)xRawTouch[1] - (int32_t)xRawTouch[3];
trC = ((int32_t)((int32_t)test1 * SCALE_FACTOR) / test2);
trD = ((int32_t)((int32_t)xPoint[1] * SCALE_FACTOR) - (trC * (int32_t)xRawTouch[1]));
// get the average and use it
_trA = (trA + trAhold) >> 1;
_trB = (trB + trBhold) >> 1;
_trC = (trC + trChold) >> 1;
_trD = (trD + trDhold) >> 1;
}
void adcraw_init(void)
{
state = IDLE; // set the state of the state machine to start the sampling
gpio_set_drive_capability(yu, GPIO_DRIVE_CAP_3);
gpio_set_drive_capability(yd, GPIO_DRIVE_CAP_3);
gpio_set_drive_capability(xl, GPIO_DRIVE_CAP_3);
gpio_set_drive_capability(xr, GPIO_DRIVE_CAP_3);
ESP_ERROR_CHECK(esp_timer_create(&periodic_timer_args, &periodic_timer));
ESP_ERROR_CHECK(esp_timer_start_periodic(periodic_timer, 5 * 1000)); //5ms (expressed as microseconds)
/*Load calibration data*/
xRawTouch[0] = TOUCHCAL_ULX;
yRawTouch[0] = TOUCHCAL_ULY;
xRawTouch[1] = TOUCHCAL_URX;
yRawTouch[1] = TOUCHCAL_URY;
xRawTouch[3] = TOUCHCAL_LLX;
yRawTouch[3] = TOUCHCAL_LLY;
xRawTouch[2] = TOUCHCAL_LRX;
yRawTouch[2] = TOUCHCAL_LRY;
TouchCalculateCalPoints();
}
static void setup_axis(gpio_num_t plus, gpio_num_t minus, gpio_num_t measure, gpio_num_t ignore)
{
// Set GPIOs:
// - Float "ignore" and "measure"
gpio_pad_select_gpio(ignore);
gpio_set_direction(ignore, GPIO_MODE_DISABLE);
gpio_set_pull_mode(ignore, GPIO_FLOATING);
gpio_pad_select_gpio(measure);
gpio_set_direction(measure, GPIO_MODE_DISABLE);
gpio_set_pull_mode(measure, GPIO_FLOATING);
// - Set "plus" to 1, "minus" to 0
gpio_config(&(gpio_config_t) {
.mode = GPIO_MODE_OUTPUT,
.pin_bit_mask = (1ULL << plus) | (1ULL << minus)
});
gpio_set_level(plus, 1);
gpio_set_level(minus, 0);
}
static void setup_adc(gpio_num_t measure)
{
// Init ADC
adc1_channel_t channel = gpio_to_adc[measure];
adc_gpio_init(ADC_UNIT_1, channel);
adc1_config_width(ADC_WIDTH_BIT_10);
adc1_config_channel_atten(channel, ADC_ATTEN_DB_11);
}
static void insert_sort(int16_t array[], uint8_t size) {
uint8_t j;
int16_t save;
for (int i = 1; i < size; i++) {
save = array[i];
for (j = i; j >= 1 && save < array[j - 1]; j--)
array[j] = array[j - 1];
array[j] = save;
}
}
static void ad_touch_handler(void *arg)
{
(void) arg;
uint8_t i;
int16_t samples[NUMSAMPLES];
switch (state) {
case IDLE:
adcX = 0;
adcY = 0;
case SET_X :
setup_axis(yd, yu, xr, xl);
setup_adc(xr);
state = READ_X;
break;
case READ_X:
for (i = 0; i < NUMSAMPLES; i++)
samples[i] = adc1_get_raw(gpio_to_adc[xr]);
insert_sort(samples, NUMSAMPLES);
temp_x = samples[NUMSAMPLES / 2];
case SET_Y :
setup_axis(xl, xr, yd, yu);
setup_adc(yd);
state = READ_Y;
break;
case READ_Y:
for (i = 0; i < NUMSAMPLES; i++)
samples[i] = adc1_get_raw(gpio_to_adc[yd]);
insert_sort(samples, NUMSAMPLES);
temp_y = samples[NUMSAMPLES / 2];
case SET_Z1 :
setup_axis(yu, xl, yd, xr);
setup_adc(yd);
state = READ_Z1;
break;
case READ_Z1:
temp_z1 = adc1_get_raw(gpio_to_adc[yd]);
case SET_Z2 :
setup_axis(yu, xl, xr, yd);
setup_adc(yd);
state = READ_Z2;
break;
case READ_Z2:
temp_z2 = adc1_get_raw(gpio_to_adc[xr]);
if (temp_z1 < TOUCHSCREEN_RESISTIVE_PRESS_THRESHOLD) {
#if CONFIG_LV_TOUCH_XY_SWAP
adcX = temp_y;
adcY = temp_x;
#else
adcX = temp_x;
adcY = temp_y;
#endif
}
else {
adcX = -1;
adcY = -1;
}
state = SET_X;
//printf("x: %d y: %d z: %d\n", adcX, adcY, temp_z1 - temp_z2);
break;
}
return;
}
static int16_t TouchGetRawX(void)
{
int16_t x = adcX;
#if CONFIG_LV_TOUCH_INVERT_X
x = 1023 - x;
#endif
return x;
}
static int16_t TouchGetX(void)
{
int16_t result = TouchGetRawX();
if (result > 0) {
result = (int16_t)((((int32_t)_trC * result) + _trD) >> TOUCHSCREEN_RESISTIVE_CALIBRATION_SCALE_FACTOR);
}
printf("x: %d\n", result);
return (result);
}
static int16_t TouchGetRawY(void)
{
int16_t y = adcY;
#if CONFIG_LV_TOUCH_INVERT_Y
y = 1023 - y;
#endif
return y;
}
static int16_t TouchGetY(void)
{
int16_t result = TouchGetRawY();
if (result > 0) {
result = (int16_t)((((int32_t)_trA * result) + (int32_t)_trB) >> TOUCHSCREEN_RESISTIVE_CALIBRATION_SCALE_FACTOR);
}
printf("y: %d\n", result);
return (result);
}
/**
* Get the current position and state of the touchpad
* @param data store the read data here
* @return false: because no more data to be read
*/
bool adcraw_read(lv_indev_drv_t * drv, lv_indev_data_t * data)
{
static int16_t last_x = 0;
static int16_t last_y = 0;
int16_t x, y;
x = TouchGetX();
y = TouchGetY();
if ((x > 0) && (y > 0)) {
data->point.x = x;
data->point.y = y;
last_x = data->point.x;
last_y = data->point.y;
data->state = LV_INDEV_STATE_PR;
}
else {
data->point.x = last_x;
data->point.y = last_y;
data->state = LV_INDEV_STATE_REL;
}
return false;
}
#endif //CONFIG_LV_TOUCH_CONTROLLER_ADCRAW
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