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SAM3U-EK: Correct polarity of the PENIRQ signal

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This commit is contained in:
Gregory Nutt 2013-06-16 14:31:18 -06:00
parent c7fd7a4e27
commit c9f1d1857c
7 changed files with 42 additions and 56 deletions
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5
ChangeLog
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@ -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).
(2013-6-16).
* configs/sam3u-ek/src/up_touchscreen.c: Fix polarity of the /PENIRQ
signal (it is active low) (2013-6-16).

10
arch/arm/src/sam34/sam_spi.c
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@ -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;

14
configs/sam3u-ek/README.txt
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@ -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

17
configs/sam3u-ek/src/sam3u-ek.h
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@ -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

4
configs/sam3u-ek/src/up_touchscreen.c
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@ -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;
}

35
drivers/input/ads7843e.c
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@ -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 */
@ -266,22 +263,6 @@ 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
*
@ -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 */

13
include/nuttx/input/ads7843e.h
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@ -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);