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author | Kumar Abhishek <abhishek.kakkar@hotmail.com> | 2012-08-16 15:14:16 +0530 |
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committer | Kumar Abhishek <abhishek.kakkar@hotmail.com> | 2012-08-16 15:14:16 +0530 |
commit | a9beec902da2348e858dcd54550d99a40c1fbe87 (patch) | |
tree | 81e88faebe2d6922aff034c650be02958e52c0a3 | |
parent | 7334da9f7f7cd9ea03a80e9e85f62fe061455caf (diff) | |
download | uGFX-a9beec902da2348e858dcd54550d99a40c1fbe87.tar.gz uGFX-a9beec902da2348e858dcd54550d99a40c1fbe87.tar.bz2 uGFX-a9beec902da2348e858dcd54550d99a40c1fbe87.zip |
XPT2046 LLD Major Update
Added 7 point median filtering to reduce noise
TOUCHPADDriver structure now encapsulates the IRQ pin, so removed
the TP_CS_ and TP_IRQ_ macros
Added generic tp_lld_read_value method to read any ADC channel from
the XPT2046, this includes on-chip temperature sensor and VBAT input
Improved SPI bus sharing, with the optional TOUCHPAD_SPI_PROLOGUE and
TOUCHPAD_SPI_EPILOGUE macros
-rw-r--r-- | drivers/touchpad/XPT2046/touchpad_lld.c | 155 | ||||
-rw-r--r-- | include/touchpad_lld.h | 65 |
2 files changed, 173 insertions, 47 deletions
diff --git a/drivers/touchpad/XPT2046/touchpad_lld.c b/drivers/touchpad/XPT2046/touchpad_lld.c index 24afcab4..16e4db79 100644 --- a/drivers/touchpad/XPT2046/touchpad_lld.c +++ b/drivers/touchpad/XPT2046/touchpad_lld.c @@ -36,9 +36,6 @@ /* Driver local definitions. */
/*===========================================================================*/
-#define TP_CS_HIGH palSetPad(TP_CS_PORT, TP_CS)
-#define TP_CS_LOW palClearPad(TP_CS_PORT, TP_CS)
-
#ifdef UNUSED
#elif defined(__GNUC__)
# define UNUSED(x) UNUSED_ ## x __attribute__((unused))
@@ -52,13 +49,15 @@ /* Driver exported variables. */
/*===========================================================================*/
-#if !defined(__DOXYGEN__)
- TOUCHPADDriver Touchpad;
-#endif
-
/*===========================================================================*/
/* 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. */
@@ -79,30 +78,104 @@ *
* @notapi
*/
-void tp_lld_init(TOUCHPADDriver *tp) {
- spiStart(tp->spid, tp->spicfg);
+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) {
- uint8_t txbuf[1];
- uint8_t rxbuf[2];
- uint16_t x;
+ 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);
+ }
- txbuf[0] = 0xd0;
- TP_CS_LOW;
- spiSend(&SPID1, 1, txbuf);
- spiReceive(&SPID1, 2, rxbuf);
- TP_CS_HIGH;
+ /* Switch on PENIRQ once again - perform a dummy read */
+ tp_lld_read_value(0xD0);
- x = rxbuf[0] << 4;
- x |= rxbuf[1] >> 4;
+ palSetPad(tpDriver->spicfg->ssport, tpDriver->spicfg->sspad);
+ TOUCHPAD_SPI_EPILOGUE();
- return x;
+#if defined(SPI_USE_MUTUAL_EXCLUSION)
+ spiReleaseBus(tpDriver->spip);
+#endif
+
+ /* Find the median - use selection sort */
+ tp_lld_filter();
+
+ return sampleBuf[3];
}
/*
@@ -111,20 +184,38 @@ uint16_t tp_lld_read_x(void) { * @notapi
*/
uint16_t tp_lld_read_y(void) {
- uint8_t txbuf[1];
- uint8_t rxbuf[2];
- uint16_t y;
+ int i;
+
+#if defined(SPI_USE_MUTUAL_EXCLUSION)
+ spiAcquireBus(tpDriver->spip);
+#endif
+
+ TOUCHPAD_SPI_PROLOGUE();
+ palClearPad(tpDriver->spicfg->ssport, tpDriver->spicfg->sspad);
- txbuf[0] = 0x90;
- TP_CS_LOW;
- spiSend(&SPID1, 1, txbuf);
- spiReceive(&SPID1, 2, rxbuf);
- TP_CS_HIGH;
+ /* 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
- y = rxbuf[0] << 4;
- y |= rxbuf[1] >> 4;
+ /* Find the median - use selection sort */
+ tp_lld_filter();
- return y;
+ return sampleBuf[3];
}
/* ---- Optional Routines ---- */
@@ -137,7 +228,7 @@ uint16_t tp_lld_read_y(void) { * @notapi
*/
uint8_t tp_lld_irq(void) {
- return (!palReadPad(TP_IRQ_PORT, TP_IRQ));
+ return (!palReadPad(tpDriver->tpIRQPort, tpDriver->tpIRQPin));
}
#endif
diff --git a/include/touchpad_lld.h b/include/touchpad_lld.h index 45a561d3..a3a7489c 100644 --- a/include/touchpad_lld.h +++ b/include/touchpad_lld.h @@ -49,41 +49,76 @@ #define TOUCHPAD_HAS_PRESSURE FALSE #endif +#ifndef TOUCHPAD_SPI_PROLOGUE + #define TOUCHPAD_SPI_PROLOGUE() +#endif + +#ifndef TOUCHPAD_SPI_EPILOGUE + #define TOUCHPAD_SPI_EPILOGUE() +#endif + /*===========================================================================*/ /* Driver types. */ /*===========================================================================*/ -typedef struct TOUCHPADDriver TOUCHPADDriver; +typedef struct _TOUCHPADDriver TOUCHPADDriver; /** * @brief Structure representing a Touchpad driver. */ -struct TOUCHPADDriver { - /* - * @brief Pointer to SPI driver. - */ - SPIDriver *spid; - - /* - * @brief SPI configuration. - */ - SPIConfig *spicfg; +struct _TOUCHPADDriver { + /* + * @brief Pointer to SPI driver. + * @note SPI driver must be enabled in mcuconf.h and halconf.h + */ + SPIDriver *spip; + + /* + * @brief Pointer to the SPI configuration structure. + * @note The lowest possible speed ~ 1-2MHz is to be used, otherwise + * will result in a lot of noise + */ + const SPIConfig *spicfg; + + /* + * @brief Touchscreen controller TPIRQ pin GPIO port + */ + ioportid_t tpIRQPort; + + /* + * @brief Touchscreen controller TPIRQ GPIO pin + * @note The interface is polled as of now, interrupt support is + * to be implemented in the future. + */ + ioportmask_t tpIRQPin; + + /* + * @brief Initialize the SPI with the configuration struct given or not + * If TRUE, spiStart is called by the init, otherwise not + * @note This is provided in such a case when SPI port is being shared + * across multiple peripherals, so not to disturb the SPI bus. + * You can use TOUCHPAD_SPI_PROLOGUE() and TOUCHPAD_SPI_EPILOGUE() + * macros to change the SPI configuration or speed before and + * after using the touchpad. An example case would be sharing the + * bus with a fast flash memory chip. + */ + bool_t direct_init; }; + /*===========================================================================*/ /* External declarations. */ /*===========================================================================*/ -#if !defined(__DOXYGEN__) - extern TOUCHPADDriver Touchpad; -#endif #ifdef __cplusplus extern "C" { #endif /* Core functions */ - void tp_lld_init(TOUCHPADDriver *tp); + void tp_lld_init(const TOUCHPADDriver *tp); + + uint16_t tp_lld_read_value(uint8_t cmd); uint16_t tp_lld_read_x(void); uint16_t tp_lld_read_y(void); |