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/*
ChibiOS/GFX - Copyright (C) 2012
Joel Bodenmann aka Tectu <joel@unormal.org>
This file is part of ChibiOS/GFX.
ChibiOS/GFX is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS/GFX is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file touchpadXPT2046/touchpad_lld.c
* @brief Touchpad Driver subsystem low level driver source.
*
* @addtogroup TOUCHPAD
* @{
*/
#include "ch.h"
#include "hal.h"
#include "touchpad.h"
#if HAL_USE_TOUCHPAD || defined(__DOXYGEN__)
/*===========================================================================*/
/* Driver local definitions. */
/*===========================================================================*/
#ifdef UNUSED
#elif defined(__GNUC__)
# define UNUSED(x) UNUSED_ ## x __attribute__((unused))
#elif defined(__LCLINT__)
# define UNUSED(x) /*@unused@*/ x
#else
# define UNUSED(x) x
#endif
/*===========================================================================*/
/* Driver exported variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver local variables. */
/*===========================================================================*/
#if !defined(__DOXYGEN__)
/* Local copy of the current touchpad driver */
static const TOUCHPADDriver *tpDriver;
static uint16_t sampleBuf[7];
#endif
/*===========================================================================*/
/* Driver local functions. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver interrupt handlers. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver exported functions. */
/*===========================================================================*/
/* ---- Required Routines ---- */
/**
* @brief Low level Touchpad driver initialization.
*
* @notapi
*/
void tp_lld_init(const TOUCHPADDriver *tp) {
tpDriver = tp;
if(tpDriver->direct_init)
spiStart(tpDriver->spip, tpDriver->spicfg);
}
/**
* @brief Reads a conversion from the touchpad
*
* @param[in] cmd The command bits to send to the touchpad
*
* @return The read value 12-bit right-justified
*
* @note This function only reads data, it is assumed that the pins are
* configured properly and the bus has been acquired beforehand
*
* @notapi
*/
uint16_t tp_lld_read_value(uint8_t cmd) {
static uint8_t txbuf[3] = {0};
static uint8_t rxbuf[3] = {0};
uint16_t ret;
txbuf[0] = cmd;
spiExchange(tpDriver->spip, 3, txbuf, rxbuf);
ret = (rxbuf[1] << 5) | (rxbuf[2] >> 3);
return ret;
}
/**
* @brief 7-point median filtering code for touchpad samples
*
* @note This is an internally used routine only.
*
* @notapi
*/
static void tp_lld_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 Reads out the X direction.
*
* @note The samples are median filtered for greater noise reduction
*
* @notapi
*/
uint16_t tp_lld_read_x(void) {
int i;
#if defined(SPI_USE_MUTUAL_EXCLUSION)
spiAcquireBus(tpDriver->spip);
#endif
TOUCHPAD_SPI_PROLOGUE();
palClearPad(tpDriver->spicfg->ssport, tpDriver->spicfg->sspad);
/* Discard the first conversion - very noisy and keep the ADC on hereafter
* till we are done with the sampling. Note that PENIRQ is disabled.
*/
tp_lld_read_value(0xD1);
for(i = 0; i < 7; i++) {
sampleBuf[i]=tp_lld_read_value(0xD1);
}
/* Switch on PENIRQ once again - perform a dummy read */
tp_lld_read_value(0xD0);
palSetPad(tpDriver->spicfg->ssport, tpDriver->spicfg->sspad);
TOUCHPAD_SPI_EPILOGUE();
#if defined(SPI_USE_MUTUAL_EXCLUSION)
spiReleaseBus(tpDriver->spip);
#endif
/* Find the median - use selection sort */
tp_lld_filter();
return sampleBuf[3];
}
/*
* @brief Reads out the Y direction.
*
* @notapi
*/
uint16_t tp_lld_read_y(void) {
int i;
#if defined(SPI_USE_MUTUAL_EXCLUSION)
spiAcquireBus(tpDriver->spip);
#endif
TOUCHPAD_SPI_PROLOGUE();
palClearPad(tpDriver->spicfg->ssport, tpDriver->spicfg->sspad);
/* Discard the first conversion - very noisy and keep the ADC on hereafter
* till we are done with the sampling. Note that PENIRQ is disabled.
*/
tp_lld_read_value(0x91);
for(i = 0; i < 7; i++) {
sampleBuf[i] = tp_lld_read_value(0x91);
}
/* Switch on PENIRQ once again - perform a dummy read */
tp_lld_read_value(0x90);
palSetPad(tpDriver->spicfg->ssport, tpDriver->spicfg->sspad);
TOUCHPAD_SPI_EPILOGUE();
#ifdef SPI_USE_MUTUAL_EXCLUSION
spiReleaseBus(tpDriver->spip);
#endif
/* Find the median - use selection sort */
tp_lld_filter();
return sampleBuf[3];
}
/* ---- Optional Routines ---- */
#if TOUCHPAD_HAS_IRQ || defined(__DOXYGEN__)
/*
* @brief for checking if touchpad is pressed or not.
*
* @return 1 if pressed / 0 if not pressed
*
* @notapi
*/
uint8_t tp_lld_irq(void) {
return (!palReadPad(tpDriver->tpIRQPort, tpDriver->tpIRQPin));
}
#endif
#if TOUCHPAD_HAS_PRESSURE || defined(__DOXYGEN__)
/*
* @brief Reads out the Z direction / pressure.
*
* @notapi
*/
uint16_t tp_lld_read_z(void) {
/* ToDo */
return 42;
}
#endif
#endif /* HAL_USE_TOUCHPAD */
/** @} */
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