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ndg/indev/AD_touch.c

384 lines
10 KiB
C

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