SAM3U-EK: Correct polarity of the PENIRQ signal

7 files changed, 42 insertions, 56 deletions

diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog
index 9f21e5769..df87260fc 100644
--- a/nuttx/ChangeLog
+++ b/nuttx/ChangeLog
@@ -4989,4 +4989,7 @@
 	  maybe it is not supposed to.  From my reading of the ADS7843 spec, it
 	  would not be appropriate to wait for the BUSY bit to de-asserted
 	  anyway (since it is only de-asserted when we read the data)
-	  (2013-6-16).
\ No newline at end of file
+	  (2013-6-16).
+	* configs/sam3u-ek/src/up_touchscreen.c: Fix polarity of the /PENIRQ
+	  signal (it is active low) (2013-6-16).
+
diff --git a/nuttx/arch/arm/src/sam34/sam_spi.c b/nuttx/arch/arm/src/sam34/sam_spi.c
index 65ebfa922..507ab2647 100644
--- a/nuttx/arch/arm/src/sam34/sam_spi.c
+++ b/nuttx/arch/arm/src/sam34/sam_spi.c
@@ -447,7 +447,7 @@ static uint32_t spi_setfrequency(FAR struct spi_dev_s *dev, uint32_t frequency)
 
   /* Configure SPI to a frequency as close as possible to the requested frequency.
    *
-   *   SPCK frequency = MCK / SCBR, or SCBR = MCK / frequency
+   *   SPCK frequency = SPI_CLK / SCBR, or SCBR = SPI_CLK / frequency
    */
 
   scbr = SAM_SPI_CLOCK / frequency;
@@ -475,11 +475,11 @@ static uint32_t spi_setfrequency(FAR struct spi_dev_s *dev, uint32_t frequency)
    * transition is 1/2 the SPCK clock period. Otherwise, the following equations
    * determine the delay:
    *
-   *   Delay Before SPCK = DLYBS / MCK
+   *   Delay Before SPCK = DLYBS / SPI_CLK
    *
    * For a 2uS delay
    *
-   *   DLYBS = MCK * 0.000002 = MCK / 500000
+   *   DLYBS = SPI_CLK * 0.000002 = SPI_CLK / 500000
    */
 
   dlybs   = SAM_SPI_CLOCK / 500000;
@@ -490,11 +490,11 @@ static uint32_t spi_setfrequency(FAR struct spi_dev_s *dev, uint32_t frequency)
    * the chip select. The delay is always inserted after each transfer and
    * before removing the chip select if needed.
    *
-   *  Delay Between Consecutive Transfers = (32 x DLYBCT) / MCK
+   *  Delay Between Consecutive Transfers = (32 x DLYBCT) / SPI_CLK
    *
    * For a 5uS delay:
    *
-   *  DLYBCT = MCK * 0.000005 / 32 = MCK / 200000 / 32
+   *  DLYBCT = SPI_CLK * 0.000005 / 32 = SPI_CLK / 200000 / 32
    */
 
   dlybct  = SAM_SPI_CLOCK / 200000 / 32;
diff --git a/nuttx/configs/sam3u-ek/README.txt b/nuttx/configs/sam3u-ek/README.txt
index 32d994329..b26b96e4a 100644
--- a/nuttx/configs/sam3u-ek/README.txt
+++ b/nuttx/configs/sam3u-ek/README.txt
@@ -581,6 +581,7 @@ Configuration sub-directories
             CONFIG_INPUT_ADS7843E=y           : Enable support for the XPT2048
             CONFIG_ADS7843E_SPIDEV=2          : Use SPI CS 2 for communication
             CONFIG_ADS7843E_SPIMODE=0         : Use SPI mode 0
+            CONFIG_ADS7843E_FREQUENCY=1000000 : SPI BAUD 1MHz
             CONFIG_ADS7843E_THRESHX=39        : These will probably need to be tuned
             CONFIG_ADS7843E_THRESHY=51
 
@@ -609,14 +610,11 @@ Configuration sub-directories
             CONFIG_DEBUG_INPUT=y              : Enable debug output from input devices
 
           STATUS:
-            2013-6-14: The touchscreen is not functional.  BUSY is initially
-            '0' when asserted says '1'.  The pend down GPIO inputis always
-            '1' and there seems to be many spurious interrupts (but not so
-            many as to lock up the system).
-
-            So there are GIO issues, but on the positive side, the driver
-            does appear to produce good touch data when touched but a lot
-            of clean-up is needed.
+            2013-6-16: The touchscreen is not functional. It seems to
+            perform good measurements but I am not getting the /PENIRQ
+            interrupt.  The interrupt is set up correctly (I can ground
+            A24 and I get the interrupt), so apparently the ADS7843E is
+            not generating interrupts.
 
   nx:
     Configures to use examples/nx using the HX834x LCD hardware on
diff --git a/nuttx/configs/sam3u-ek/src/sam3u-ek.h b/nuttx/configs/sam3u-ek/src/sam3u-ek.h
index af68df42a..a9841dcc6 100644
--- a/nuttx/configs/sam3u-ek/src/sam3u-ek.h
+++ b/nuttx/configs/sam3u-ek/src/sam3u-ek.h
@@ -143,14 +143,19 @@
  *
  * The IRQ is active low and pulled up.
  *
+ * Pen Interrupt. Open anode output, requires 10kO to 100kO pull-up resistor
+ * externally.  There is a 100KO pull-up on the SAM3U-EK board so no additional
+ * pull-up should be required.
+ *
  * BUSY is high impedance when CS is high (not selected).  When CS is
  * is low, BUSY is active high.  Since the pin is pulled up, it will appear
- * busy if CS is not selected.
+ * busy if CS is not selected (there is no pull-up onboard).
  */
 
 #define GPIO_TCS_IRQ  (GPIO_INPUT | GPIO_CFG_PULLUP | GPIO_INT_BOTHEDGES | \
                        GPIO_PORT_PIOA | GPIO_PIN24)
-#define GPIO_TCS_BUSY (GPIO_INPUT | GPIO_CFG_PULLUP | GPIO_PORT_PIOA | GPIO_PIN2)
+#define GPIO_TCS_BUSY (GPIO_INPUT | GPIO_CFG_PULLUP | GPIO_PORT_PIOA | \
+                       GPIO_PIN2)
 
 #define SAM_TCS_IRQ   SAM_IRQ_PA24
 
@@ -165,10 +170,10 @@
 
 /* BUTTONS */
 
-#define GPIO_BUTTON1  (GPIO_INPUT | GPIO_CFG_PULLUP | GPIO_CFG_DEGLITCH | GPIO_INT_BOTHEDGES | \
-                       GPIO_PORT_PIOA | GPIO_PIN18)
-#define GPIO_BUTTON2  (GPIO_INPUT | GPIO_CFG_PULLUP | GPIO_CFG_DEGLITCH | GPIO_INT_BOTHEDGES | \
-                       GPIO_PORT_PIOA | GPIO_PIN19)
+#define GPIO_BUTTON1  (GPIO_INPUT | GPIO_CFG_PULLUP | GPIO_CFG_DEGLITCH | \
+                       GPIO_INT_BOTHEDGES | GPIO_PORT_PIOA | GPIO_PIN18)
+#define GPIO_BUTTON2  (GPIO_INPUT | GPIO_CFG_PULLUP | GPIO_CFG_DEGLITCH | \
+                       GPIO_INT_BOTHEDGES | GPIO_PORT_PIOA | GPIO_PIN19)
 
 #define IRQ_BUTTON1   SAM_IRQ_PA18
 #define IRQ_BUTTON2   SAM_IRQ_PA19
diff --git a/nuttx/configs/sam3u-ek/src/up_touchscreen.c b/nuttx/configs/sam3u-ek/src/up_touchscreen.c
index 46a814c6f..41799d5e1 100644
--- a/nuttx/configs/sam3u-ek/src/up_touchscreen.c
+++ b/nuttx/configs/sam3u-ek/src/up_touchscreen.c
@@ -201,9 +201,9 @@ static bool tsc_busy(FAR struct ads7843e_config_s *state)
 
 static bool tsc_pendown(FAR struct ads7843e_config_s *state)
 {
-  /* REVISIT:  This might need to be inverted */
+  /* The /PENIRQ value is active low */
 
-  bool pendown = sam_gpioread(GPIO_TCS_IRQ);
+  bool pendown = !sam_gpioread(GPIO_TCS_IRQ);
   ivdbg("pendown:%d\n", pendown);
   return pendown;
 }
diff --git a/nuttx/drivers/input/ads7843e.c b/nuttx/drivers/input/ads7843e.c
index 7d1a0c3ea..567e332b6 100644
--- a/nuttx/drivers/input/ads7843e.c
+++ b/nuttx/drivers/input/ads7843e.c
@@ -104,9 +104,6 @@ static void ads7843e_lock(FAR struct spi_dev_s *spi);
 static void ads7843e_unlock(FAR struct spi_dev_s *spi);
 #endif
 
-#if 0
-static inline void ads7843e_waitbusy(FAR struct ads7843e_dev_s *priv);
-#endif
 static uint16_t ads7843e_sendcmd(FAR struct ads7843e_dev_s *priv, uint8_t cmd);
 
 /* Interrupts and data sampling */
@@ -267,22 +264,6 @@ static inline void ads7843e_configspi(FAR struct spi_dev_s *spi)
 #endif
 
 /****************************************************************************
- * Name: ads7843e_waitbusy
- ****************************************************************************/
-
-#if 0 /* Not used */
-static inline void ads7843e_waitbusy(FAR struct ads7843e_dev_s *priv)
-{
-  /* BUSY is high impedance when the ads7843e not selected.  When the
-   * ads7843e selected, BUSY is active high.  Hence, it is necessary to have
-   * the ads7843e selected when this function is called.
-   */
-
-  while (priv->config->busy(priv->config));
-}
-#endif
-
-/****************************************************************************
  * Name: ads7843e_sendcmd
  *
  * Description.
@@ -312,8 +293,8 @@ static inline void ads7843e_waitbusy(FAR struct ads7843e_dev_s *priv)
  *   nominally 2 microseconds.
  *
  *   So what good is this BUSY?  Many boards do not even bother to bring it
- *   to the MCU.  It looks like busy will stick high until we read the data
- *   so it does not really make any sense to wait on it.
+ *   to the MCU.  Busy will stick high until we read the data so you cannot
+ *   wait on it before reading.
  *
  ****************************************************************************/
 
@@ -330,15 +311,9 @@ static uint16_t ads7843e_sendcmd(FAR struct ads7843e_dev_s *priv, uint8_t cmd)
 
   (void)SPI_SEND(priv->spi, cmd);
 
-#if 1
   /* Wait a tiny amount to make sure that the aquisition time is complete */
 
    up_udelay(3); /* 3 microseconds */
-#else
-  /* Wait until busy is no longer asserted */
-
-  ads7843e_waitbusy(priv);
-#endif
 
   /* Read the 12-bit data (LS 4 bits will be padded with zero) */
 
@@ -372,7 +347,7 @@ static void ads7843e_notify(FAR struct ads7843e_dev_s *priv)
        * is no longer available.
        */
 
-      sem_post(&priv->waitsem); 
+      sem_post(&priv->waitsem);
     }
 
   /* If there are threads waiting on poll() for ADS7843E data to become available,
@@ -484,7 +459,7 @@ static int ads7843e_waitsample(FAR struct ads7843e_dev_s *priv,
   while (ads7843e_sample(priv, sample) < 0)
     {
       /* Wait for a change in the ADS7843E state */
- 
+
       ivdbg("Waiting..\n");
       priv->nwaiters++;
       ret = sem_wait(&priv->waitsem);
@@ -1283,7 +1258,7 @@ int ads7843e_register(FAR struct spi_dev_s *spi,
   ads7843e_configspi(spi);
 
   /* Enable the PEN IRQ */
-  
+
   ads7843e_sendcmd(priv, ADS7843_CMD_ENABPENIRQ);
 
   /* Unlock the bus */
diff --git a/nuttx/include/nuttx/input/ads7843e.h b/nuttx/include/nuttx/input/ads7843e.h
index fe4382f2f..dc8b97faf 100644
--- a/nuttx/include/nuttx/input/ads7843e.h
+++ b/nuttx/include/nuttx/input/ads7843e.h
@@ -126,10 +126,15 @@ struct ads7843e_config_s
    * interrupts should be configured on both rising and falling edges
    * so that contact and loss-of-contact events can be detected.
    *
-   * attach  - Attach the ADS7843E interrupt handler to the GPIO interrupt
-   * enable  - Enable or disable the GPIO interrupt
-   * clear   - Acknowledge/clear any pending GPIO interrupt
-   * pendown - Return the state of the pen down GPIO input
+   *   attach  - Attach the ADS7843E interrupt handler to the GPIO interrupt
+   *   enable  - Enable or disable the GPIO interrupt
+   *   clear   - Acknowledge/clear any pending GPIO interrupt
+   *   busy    - Return the state of the BUSY GPIO input (for debug only)
+   *   pendown - Return the state of the pen down GPIO input
+   *
+   * NOTE: The busy() method is not currently used by the driver.  The BUSY
+   * signal is only an informative signal that is raised after a command has
+   * been send but before the sample data has been obtained.
    */
 
   int  (*attach)(FAR struct ads7843e_config_s *state, xcpt_t isr);