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175 lines
3.6 KiB
C
175 lines
3.6 KiB
C
/**
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* @file XPT2046.c
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*
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*/
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/*********************
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* INCLUDES
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*********************/
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#include "XPT2046.h"
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#if USE_XPT2046
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#include <stddef.h>
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#include LV_DRV_INDEV_INCLUDE
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#include LV_DRV_DELAY_INCLUDE
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/*********************
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* DEFINES
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*********************/
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#define CMD_X_READ 0b10010000
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#define CMD_Y_READ 0b11010000
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/**********************
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* TYPEDEFS
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**********************/
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/**********************
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* STATIC PROTOTYPES
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**********************/
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static void xpt2046_corr(int16_t * x, int16_t * y);
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static void xpt2046_avg(int16_t * x, int16_t * y);
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/**********************
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* STATIC VARIABLES
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**********************/
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int16_t avg_buf_x[XPT2046_AVG];
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int16_t avg_buf_y[XPT2046_AVG];
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uint8_t avg_last;
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/**********************
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* MACROS
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**********************/
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/**********************
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* GLOBAL FUNCTIONS
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**********************/
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/**
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* Initialize the XPT2046
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*/
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void xpt2046_init(void)
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{
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}
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/**
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* Get the current position and state of the touchpad
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* @param data store the read data here
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* @return void
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*/
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void xpt2046_read(lv_indev_drv_t * indev_drv, lv_indev_data_t * data)
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{
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static int16_t last_x = 0;
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static int16_t last_y = 0;
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uint8_t buf;
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int16_t x = 0;
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int16_t y = 0;
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uint8_t irq = LV_DRV_INDEV_IRQ_READ;
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if(irq == 0) {
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LV_DRV_INDEV_SPI_CS(0);
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LV_DRV_INDEV_SPI_XCHG_BYTE(CMD_X_READ); /*Start x read*/
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buf = LV_DRV_INDEV_SPI_XCHG_BYTE(0); /*Read x MSB*/
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x = buf << 8;
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buf = LV_DRV_INDEV_SPI_XCHG_BYTE(CMD_Y_READ); /*Until x LSB converted y command can be sent*/
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x += buf;
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buf = LV_DRV_INDEV_SPI_XCHG_BYTE(0); /*Read y MSB*/
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y = buf << 8;
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buf = LV_DRV_INDEV_SPI_XCHG_BYTE(0); /*Read y LSB*/
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y += buf;
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/*Normalize Data*/
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x = x >> 3;
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y = y >> 3;
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xpt2046_corr(&x, &y);
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xpt2046_avg(&x, &y);
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last_x = x;
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last_y = y;
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data->state = LV_INDEV_STATE_PR;
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LV_DRV_INDEV_SPI_CS(1);
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} else {
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x = last_x;
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y = last_y;
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avg_last = 0;
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data->state = LV_INDEV_STATE_REL;
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}
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data->point.x = x;
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data->point.y = y;
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data->continue_reading = false; /* No more data to be read */
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}
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/**********************
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* STATIC FUNCTIONS
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**********************/
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static void xpt2046_corr(int16_t * x, int16_t * y)
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{
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#if XPT2046_XY_SWAP != 0
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int16_t swap_tmp;
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swap_tmp = *x;
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*x = *y;
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*y = swap_tmp;
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#endif
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if((*x) > XPT2046_X_MIN)(*x) -= XPT2046_X_MIN;
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else(*x) = 0;
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if((*y) > XPT2046_Y_MIN)(*y) -= XPT2046_Y_MIN;
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else(*y) = 0;
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(*x) = (uint32_t)((uint32_t)(*x) * XPT2046_HOR_RES) /
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(XPT2046_X_MAX - XPT2046_X_MIN);
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(*y) = (uint32_t)((uint32_t)(*y) * XPT2046_VER_RES) /
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(XPT2046_Y_MAX - XPT2046_Y_MIN);
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#if XPT2046_X_INV != 0
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(*x) = XPT2046_HOR_RES - (*x);
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#endif
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#if XPT2046_Y_INV != 0
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(*y) = XPT2046_VER_RES - (*y);
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#endif
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}
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static void xpt2046_avg(int16_t * x, int16_t * y)
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{
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/*Shift out the oldest data*/
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uint8_t i;
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for(i = XPT2046_AVG - 1; i > 0 ; i--) {
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avg_buf_x[i] = avg_buf_x[i - 1];
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avg_buf_y[i] = avg_buf_y[i - 1];
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}
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/*Insert the new point*/
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avg_buf_x[0] = *x;
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avg_buf_y[0] = *y;
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if(avg_last < XPT2046_AVG) avg_last++;
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/*Sum the x and y coordinates*/
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int32_t x_sum = 0;
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int32_t y_sum = 0;
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for(i = 0; i < avg_last ; i++) {
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x_sum += avg_buf_x[i];
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y_sum += avg_buf_y[i];
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}
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/*Normalize the sums*/
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(*x) = (int32_t)x_sum / avg_last;
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(*y) = (int32_t)y_sum / avg_last;
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}
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#endif
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