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384 lines
10 KiB
C
384 lines
10 KiB
C
/**
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* @file AD_touch.c
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*
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*/
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#include "AD_touch.h"
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#if USE_AD_TOUCH
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#include LV_DRV_INDEV_INCLUDE
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#include LV_DRV_DELAY_INCLUDE
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#define SAMPLE_POINTS 4
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#define CALIBRATIONINSET 20 // range 0 <= CALIBRATIONINSET <= 40
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#define RESISTIVETOUCH_AUTO_SAMPLE_MODE
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#define TOUCHSCREEN_RESISTIVE_PRESS_THRESHOLD 350 // between 0-0x03ff the lesser this value
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// Current ADC values for X and Y channels
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int16_t adcX = 0;
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int16_t adcY = 0;
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volatile unsigned int adcTC = 0;
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// coefficient values
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volatile long _trA;
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volatile long _trB;
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volatile long _trC;
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volatile long _trD;
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volatile int16_t xRawTouch[SAMPLE_POINTS] = {TOUCHCAL_ULX, TOUCHCAL_URX, TOUCHCAL_LRX, TOUCHCAL_LLX};
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volatile int16_t yRawTouch[SAMPLE_POINTS] = {TOUCHCAL_ULY, TOUCHCAL_URY, TOUCHCAL_LRY, TOUCHCAL_LLY};
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#define TOUCHSCREEN_RESISTIVE_CALIBRATION_SCALE_FACTOR 8
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// use this scale factor to avoid working in floating point numbers
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#define SCALE_FACTOR (1 << TOUCHSCREEN_RESISTIVE_CALIBRATION_SCALE_FACTOR)
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typedef enum {
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IDLE, //0
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SET_X, //1
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RUN_X, //2
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GET_X, //3
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RUN_CHECK_X, //4
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CHECK_X, //5
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SET_Y, //6
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RUN_Y, //7
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GET_Y, //8
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CHECK_Y, //9
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SET_VALUES, //10
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GET_POT, //11
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RUN_POT //12
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} TOUCH_STATES;
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volatile TOUCH_STATES state = IDLE;
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#define CAL_X_INSET (((GetMaxX() + 1) * (CALIBRATIONINSET >> 1)) / 100)
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#define CAL_Y_INSET (((GetMaxY() + 1) * (CALIBRATIONINSET >> 1)) / 100)
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int stat;
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int16_t temp_x, temp_y;
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static int16_t TouchGetX(void);
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static int16_t TouchGetRawX(void);
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static int16_t TouchGetY(void);
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static int16_t TouchGetRawY(void);
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static int16_t TouchDetectPosition(void);
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static void TouchCalculateCalPoints(void);
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/********************************************************************/
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void ad_touch_init(void)
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{
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// Initialize ADC for auto sampling mode
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AD1CON1 = 0; // reset
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AD1CON2 = 0; // AVdd, AVss, int every conversion, MUXA only
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AD1CON3 = 0x1FFF; // 31 Tad auto-sample, Tad = 256*Tcy
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AD1CON1 = 0x80E0; // Turn on A/D module, use auto-convert
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ADPCFG_XPOS = RESISTIVETOUCH_ANALOG;
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ADPCFG_YPOS = RESISTIVETOUCH_ANALOG;
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AD1CSSL = 0; // No scanned inputs
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state = SET_X; // set the state of the state machine to start the sampling
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/*Load calibration data*/
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xRawTouch[0] = TOUCHCAL_ULX;
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yRawTouch[0] = TOUCHCAL_ULY;
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xRawTouch[1] = TOUCHCAL_URX;
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yRawTouch[1] = TOUCHCAL_URY;
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xRawTouch[3] = TOUCHCAL_LLX;
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yRawTouch[3] = TOUCHCAL_LLY;
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xRawTouch[2] = TOUCHCAL_LRX;
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yRawTouch[2] = TOUCHCAL_LRY;
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TouchCalculateCalPoints();
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}
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/*Use this in lv_indev_drv*/
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bool ad_touch_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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int16_t x, y;
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x = TouchGetX();
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y = TouchGetY();
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if((x > 0) && (y > 0)) {
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data->point.x = x;
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data->point.y = y;
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last_x = data->point.x;
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last_y = data->point.y;
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data->state = LV_INDEV_STATE_PR;
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} else {
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data->point.x = last_x;
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data->point.y = last_y;
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data->state = LV_INDEV_STATE_REL;
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}
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return false;
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}
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/* Call periodically (e.g. in every 1 ms) to handle reading with ADC*/
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int16_t ad_touch_handler(void)
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{
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static int16_t tempX, tempY;
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int16_t temp;
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switch(state) {
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case IDLE:
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adcX = 0;
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adcY = 0;
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break;
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case SET_VALUES:
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if(!TOUCH_ADC_DONE)
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break;
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if((WORD)TOUCHSCREEN_RESISTIVE_PRESS_THRESHOLD < (WORD)ADC1BUF0) {
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adcX = 0;
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adcY = 0;
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} else {
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adcX = tempX;
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adcY = tempY;
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}
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state = SET_X;
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return 1; // touch screen acquisition is done
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case SET_X:
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TOUCH_ADC_INPUT_SEL = ADC_XPOS;
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ResistiveTouchScreen_XPlus_Config_As_Input();
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ResistiveTouchScreen_YPlus_Config_As_Input();
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ResistiveTouchScreen_XMinus_Config_As_Input();
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ResistiveTouchScreen_YMinus_Drive_Low();
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ResistiveTouchScreen_YMinus_Config_As_Output();
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ADPCFG_YPOS = RESISTIVETOUCH_DIGITAL; // set to digital pin
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ADPCFG_XPOS = RESISTIVETOUCH_ANALOG; // set to analog pin
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TOUCH_ADC_START = 1; // run conversion
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state = CHECK_X;
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break;
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case CHECK_X:
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case CHECK_Y:
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if(TOUCH_ADC_DONE == 0) {
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break;
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}
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if((WORD)TOUCHSCREEN_RESISTIVE_PRESS_THRESHOLD > (WORD)ADC1BUF0) {
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if(state == CHECK_X) {
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ResistiveTouchScreen_YPlus_Drive_High();
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ResistiveTouchScreen_YPlus_Config_As_Output();
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tempX = 0;
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state = RUN_X;
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} else {
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ResistiveTouchScreen_XPlus_Drive_High();
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ResistiveTouchScreen_XPlus_Config_As_Output();
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tempY = 0;
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state = RUN_Y;
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}
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} else {
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adcX = 0;
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adcY = 0;
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state = SET_X;
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return 1; // touch screen acquisition is done
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break;
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}
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case RUN_X:
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case RUN_Y:
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TOUCH_ADC_START = 1;
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state = (state == RUN_X) ? GET_X : GET_Y;
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// no break needed here since the next state is either GET_X or GET_Y
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break;
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case GET_X:
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case GET_Y:
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if(!TOUCH_ADC_DONE)
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break;
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temp = ADC1BUF0;
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if(state == GET_X) {
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if(temp != tempX) {
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tempX = temp;
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state = RUN_X;
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break;
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}
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} else {
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if(temp != tempY) {
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tempY = temp;
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state = RUN_Y;
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break;
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}
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}
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if(state == GET_X)
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ResistiveTouchScreen_YPlus_Config_As_Input();
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else
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ResistiveTouchScreen_XPlus_Config_As_Input();
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TOUCH_ADC_START = 1;
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state = (state == GET_X) ? SET_Y : SET_VALUES;
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break;
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case SET_Y:
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if(!TOUCH_ADC_DONE)
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break;
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if((WORD)TOUCHSCREEN_RESISTIVE_PRESS_THRESHOLD < (WORD)ADC1BUF0) {
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adcX = 0;
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adcY = 0;
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state = SET_X;
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return 1; // touch screen acquisition is done
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break;
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}
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TOUCH_ADC_INPUT_SEL = ADC_YPOS;
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ResistiveTouchScreen_XPlus_Config_As_Input();
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ResistiveTouchScreen_YPlus_Config_As_Input();
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ResistiveTouchScreen_XMinus_Drive_Low();
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ResistiveTouchScreen_XMinus_Config_As_Output();
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ResistiveTouchScreen_YMinus_Config_As_Input();
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ADPCFG_YPOS = RESISTIVETOUCH_ANALOG; // set to analog pin
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ADPCFG_XPOS = RESISTIVETOUCH_DIGITAL; // set to digital pin
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TOUCH_ADC_START = 1; // run conversion
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state = CHECK_Y;
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break;
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default:
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state = SET_X;
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return 1; // touch screen acquisition is done
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}
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stat = state;
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temp_x = adcX;
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temp_y = adcY;
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return 0; // touch screen acquisition is not done
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}
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/**********************
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* STATIC FUNCTIONS
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**********************/
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/********************************************************************/
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static int16_t TouchGetX(void)
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{
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long result;
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result = TouchGetRawX();
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if(result > 0) {
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result = (long)((((long)_trC * result) + _trD) >> TOUCHSCREEN_RESISTIVE_CALIBRATION_SCALE_FACTOR);
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}
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return ((int16_t)result);
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}
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/********************************************************************/
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static int16_t TouchGetRawX(void)
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{
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#ifdef TOUCHSCREEN_RESISTIVE_SWAP_XY
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return adcY;
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#else
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return adcX;
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#endif
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}
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/********************************************************************/
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static int16_t TouchGetY(void)
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{
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long result;
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result = TouchGetRawY();
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if(result > 0) {
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result = (long)((((long)_trA * result) + (long)_trB) >> TOUCHSCREEN_RESISTIVE_CALIBRATION_SCALE_FACTOR);
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}
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return ((int16_t)result);
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}
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/********************************************************************/
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static int16_t TouchGetRawY(void)
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{
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#ifdef TOUCHSCREEN_RESISTIVE_SWAP_XY
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return adcX;
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#else
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return adcY;
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#endif
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}
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static void TouchCalculateCalPoints(void)
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{
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long trA, trB, trC, trD; // variables for the coefficients
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long trAhold, trBhold, trChold, trDhold;
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long test1, test2; // temp variables (must be signed type)
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int16_t xPoint[SAMPLE_POINTS], yPoint[SAMPLE_POINTS];
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yPoint[0] = yPoint[1] = CAL_Y_INSET;
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yPoint[2] = yPoint[3] = (GetMaxY() - CAL_Y_INSET);
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xPoint[0] = xPoint[3] = CAL_X_INSET;
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xPoint[1] = xPoint[2] = (GetMaxX() - CAL_X_INSET);
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// calculate points transfer functiona
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// based on two simultaneous equations solve for the
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// constants
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// use sample points 1 and 4
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// Dy1 = aTy1 + b; Dy4 = aTy4 + b
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// Dx1 = cTx1 + d; Dy4 = aTy4 + b
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test1 = (long)yPoint[0] - (long)yPoint[3];
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test2 = (long)yRawTouch[0] - (long)yRawTouch[3];
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trA = ((long)((long)test1 * SCALE_FACTOR) / test2);
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trB = ((long)((long)yPoint[0] * SCALE_FACTOR) - (trA * (long)yRawTouch[0]));
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test1 = (long)xPoint[0] - (long)xPoint[2];
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test2 = (long)xRawTouch[0] - (long)xRawTouch[2];
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trC = ((long)((long)test1 * SCALE_FACTOR) / test2);
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trD = ((long)((long)xPoint[0] * SCALE_FACTOR) - (trC * (long)xRawTouch[0]));
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trAhold = trA;
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trBhold = trB;
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trChold = trC;
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trDhold = trD;
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// use sample points 2 and 3
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// Dy2 = aTy2 + b; Dy3 = aTy3 + b
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// Dx2 = cTx2 + d; Dy3 = aTy3 + b
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test1 = (long)yPoint[1] - (long)yPoint[2];
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test2 = (long)yRawTouch[1] - (long)yRawTouch[2];
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trA = ((long)(test1 * SCALE_FACTOR) / test2);
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trB = ((long)((long)yPoint[1] * SCALE_FACTOR) - (trA * (long)yRawTouch[1]));
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test1 = (long)xPoint[1] - (long)xPoint[3];
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test2 = (long)xRawTouch[1] - (long)xRawTouch[3];
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trC = ((long)((long)test1 * SCALE_FACTOR) / test2);
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trD = ((long)((long)xPoint[1] * SCALE_FACTOR) - (trC * (long)xRawTouch[1]));
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// get the average and use the average
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_trA = (trA + trAhold) >> 1;
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_trB = (trB + trBhold) >> 1;
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_trC = (trC + trChold) >> 1;
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_trD = (trD + trDhold) >> 1;
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}
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#endif
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