lvgl_esp32_drivers/lvgl_touch/xpt2046.c

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/**
* @file XPT2046.c
*
*/
/*********************
* INCLUDES
*********************/
#include "xpt2046.h"
#include "esp_system.h"
#include "driver/gpio.h"
#include "tp_spi.h"
#include <stddef.h>
/*********************
* DEFINES
*********************/
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#define CMD_X_READ 0b10010000 // NOTE: XPT2046 data sheet says this is actually Y
#define CMD_Y_READ 0b11010000 // NOTE: XPT2046 data sheet says this is actually X
#define CMD_Z1_READ 0b10110000
#define CMD_Z2_READ 0b11000000
/**********************
* TYPEDEFS
**********************/
typedef enum {
TOUCH_NOT_DETECTED = 0,
TOUCH_DETECTED = 1,
} xpt2046_touch_detect_t;
/**********************
* STATIC PROTOTYPES
**********************/
static void xpt2046_corr(int16_t * x, int16_t * y);
static void xpt2046_avg(int16_t * x, int16_t * y);
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static int16_t xpt2046_cmd(uint8_t cmd);
static xpt2046_touch_detect_t xpt2048_is_touch_detected();
/**********************
* STATIC VARIABLES
**********************/
int16_t avg_buf_x[XPT2046_AVG];
int16_t avg_buf_y[XPT2046_AVG];
uint8_t avg_last;
/**********************
* MACROS
**********************/
/**********************
* GLOBAL FUNCTIONS
**********************/
/**
* Initialize the XPT2046
*/
void xpt2046_init(void)
{
LV_LOG_INFO("Initialization");
#if XPT2046_TOUCH_IRQ || XPT2046_TOUCH_IRQ_PRESS
gpio_config_t irq_config = {
.pin_bit_mask = BIT64(XPT2046_IRQ),
.mode = GPIO_MODE_INPUT,
.pull_up_en = GPIO_PULLUP_DISABLE,
.pull_down_en = GPIO_PULLDOWN_DISABLE,
.intr_type = GPIO_INTR_DISABLE,
};
esp_err_t ret = gpio_config(&irq_config);
assert(ret == ESP_OK);
#endif
}
/**
* 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 xpt2046_read(lv_indev_drv_t * drv, lv_indev_data_t * data)
{
static int16_t last_x = 0;
static int16_t last_y = 0;
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bool valid = false;
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int16_t x = last_x;
int16_t y = last_y;
if (xpt2048_is_touch_detected() == TOUCH_DETECTED)
{
valid = true;
x = xpt2046_cmd(CMD_X_READ);
y = xpt2046_cmd(CMD_Y_READ);
LV_LOG_INFO("P(%d,%d)", x, y);
/*Normalize Data back to 12-bits*/
x = x >> 4;
y = y >> 4;
LV_LOG_INFO("P_norm(%d,%d)", x, y);
xpt2046_corr(&x, &y);
xpt2046_avg(&x, &y);
last_x = x;
last_y = y;
LV_LOG_INFO("x = %d, y = %d", x, y);
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}
else
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{
avg_last = 0;
}
data->point.x = x;
data->point.y = y;
data->state = valid == false ? LV_INDEV_STATE_REL : LV_INDEV_STATE_PR;
return false;
}
/**********************
* STATIC FUNCTIONS
**********************/
static xpt2046_touch_detect_t xpt2048_is_touch_detected()
{
// check IRQ pin if we IRQ or IRQ and preessure
#if XPT2046_TOUCH_IRQ || XPT2046_TOUCH_IRQ_PRESS
uint8_t irq = gpio_get_level(XPT2046_IRQ);
if (irq != 0) {
return TOUCH_NOT_DETECTED;
}
#endif
// check pressure if we are pressure or IRQ and pressure
#if XPT2046_TOUCH_PRESS || XPT2046_TOUCH_IRQ_PRESS
int16_t z1 = xpt2046_cmd(CMD_Z1_READ) >> 3;
int16_t z2 = xpt2046_cmd(CMD_Z2_READ) >> 3;
// this is not what the confusing datasheet says but it seems to
// be enough to detect real touches on the panel
int16_t z = z1 + 4096 - z2;
if (z < XPT2046_TOUCH_THRESHOLD)
{
return TOUCH_NOT_DETECTED;
}
#endif
return TOUCH_DETECTED;
}
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static int16_t xpt2046_cmd(uint8_t cmd)
{
uint8_t data[2];
tp_spi_read_reg(cmd, data, 2);
int16_t val = (data[0] << 8) | data[1];
return val;
}
static void xpt2046_corr(int16_t * x, int16_t * y)
{
#if XPT2046_XY_SWAP != 0
int16_t swap_tmp;
swap_tmp = *x;
*x = *y;
*y = swap_tmp;
#endif
if((*x) > XPT2046_X_MIN)(*x) -= XPT2046_X_MIN;
else(*x) = 0;
if((*y) > XPT2046_Y_MIN)(*y) -= XPT2046_Y_MIN;
else(*y) = 0;
(*x) = (uint32_t)((uint32_t)(*x) * LV_HOR_RES) /
(XPT2046_X_MAX - XPT2046_X_MIN);
(*y) = (uint32_t)((uint32_t)(*y) * LV_VER_RES) /
(XPT2046_Y_MAX - XPT2046_Y_MIN);
#if XPT2046_X_INV != 0
(*x) = LV_HOR_RES - (*x);
#endif
#if XPT2046_Y_INV != 0
(*y) = LV_VER_RES - (*y);
#endif
}
static void xpt2046_avg(int16_t * x, int16_t * y)
{
/*Shift out the oldest data*/
uint8_t i;
for(i = XPT2046_AVG - 1; i > 0 ; i--) {
avg_buf_x[i] = avg_buf_x[i - 1];
avg_buf_y[i] = avg_buf_y[i - 1];
}
/*Insert the new point*/
avg_buf_x[0] = *x;
avg_buf_y[0] = *y;
if(avg_last < XPT2046_AVG) avg_last++;
/*Sum the x and y coordinates*/
int32_t x_sum = 0;
int32_t y_sum = 0;
for(i = 0; i < avg_last ; i++) {
x_sum += avg_buf_x[i];
y_sum += avg_buf_y[i];
}
/*Normalize the sums*/
(*x) = (int32_t)x_sum / avg_last;
(*y) = (int32_t)y_sum / avg_last;
}