ugfx/drivers/ginput/touch/MCU/ginput_lld_mouse.c

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/*
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* This file is subject to the terms of the GFX License. If a copy of
* the license was not distributed with this file, you can obtain one at:
*
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* http://ugfx.org/license.html
*/
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/**
* @file drivers/ginput/touch/MCU/ginput_lld_mouse.c
* @brief GINPUT Touch low level driver source for the MCU.
*
* @defgroup Mouse Mouse
* @ingroup GINPUT
*
* @{
*/
#include "gfx.h"
#if (GFX_USE_GINPUT && GINPUT_NEED_MOUSE) /*|| defined(__DOXYGEN__)*/
#include "src/ginput/driver_mouse.h"
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#include "ginput_lld_mouse_board.h"
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static uint16_t sampleBuf[7];
/**
* @brief 7-point median filtering code for touchscreen samples
*
* @note This is an internally used routine only.
*
* @notapi
*/
static void filter(void) {
uint16_t temp;
int i,j;
for(i = 0; i < 4; i++) {
for(j = i; j < 7; j++) {
if(sampleBuf[i] > sampleBuf[j]) {
/* Swap the values */
temp = sampleBuf[i];
sampleBuf[i] = sampleBuf[j];
sampleBuf[j] = temp;
}
}
}
}
/**
* @brief Initialise the mouse/touch.
*
* @notapi
*/
void ginput_lld_mouse_init(void) {
init_board();
}
/**
* @brief Read the mouse/touch position.
*
* @param[in] pt A pointer to the structure to fill
*
* @note We use a 7 sample medium filter on each coordinate to remove analogue noise.
* @note During touch transition the ADC can return some very strange
* results. To fix this behaviour we don't return until
* we have tested the touch is in the same state at both the beginning
* and the end of the reading.
* @note Whilst x and y can return readings in any range so long as it fits in 16 bits,
* the z value must be ranged by the board file to be a rough percentage. Anything
* greater than 80% pressure is a touch.
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*
* @notapi
*/
void ginput_lld_mouse_get_reading(MouseReading *pt) {
uint16_t i;
// Obtain access to the bus
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aquire_bus();
// Read the ADC for z, x, y and then z again
while(1) {
setup_z();
for(i = 0; i < 7; i++)
sampleBuf[i] = read_z();
filter();
pt->z = (coord_t)sampleBuf[3];
setup_x();
for(i = 0; i < 7; i++)
sampleBuf[i] = read_x();
filter();
pt->x = (coord_t)sampleBuf[3];
setup_y();
for(i = 0; i < 7; i++)
sampleBuf[i] = read_y();
filter();
pt->y = (coord_t)sampleBuf[3];
pt->buttons = pt->z >= 80 ? GINPUT_TOUCH_PRESSED : 0;
setup_z();
for(i = 0; i < 7; i++)
sampleBuf[i] = read_z();
filter();
i = (coord_t)sampleBuf[3] >= 80 ? GINPUT_TOUCH_PRESSED : 0;
if (pt->buttons == i)
break;
}
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// Release the bus
release_bus();
}
#endif /* GFX_USE_GINPUT && GINPUT_NEED_MOUSE */
/** @} */