tinySA/os/hal/platforms/AT91SAM7/adc_lld.c

/*
    ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
                 2011,2012,2013 Giovanni Di Sirio.

    This file is part of ChibiOS/RT.

    ChibiOS/RT 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/RT 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/>.
*/
/*
   This file has been contributed by:
		Andrew Hannam aka inmarket.
*/
/**
 * @file    AT91SAM7/adc_lld.c
 * @brief   AT91SAM7 ADC subsystem low level driver source.
 *
 * @addtogroup ADC
 * @{
 */

#include "ch.h"
#include "hal.h"

#if HAL_USE_ADC || defined(__DOXYGEN__)

/**
 * @brief	ADC1 Prescaler
 * @detail	Prescale = RoundUp(MCK / 2 / ADCClock - 1)
 */
#if ((((MCK/2)+(AT91_ADC1_CLOCK-1))/AT91_ADC1_CLOCK)-1) > 255
	#define AT91_ADC1_PRESCALE	255
#else
	#define AT91_ADC1_PRESCALE	((((MCK/2)+(AT91_ADC1_CLOCK-1))/AT91_ADC1_CLOCK)-1)
#endif

/**
 * @brief	ADC1 Startup Time
 * @details	Startup = RoundUp(ADCClock / 400,000 - 1)
 * @note	Corresponds to a startup delay > 20uS (as required from the datasheet)
 */
#if (((AT91_ADC1_CLOCK+399999)/400000)-1) > 127
	#define AT91_ADC1_STARTUP	127
#else
	#define AT91_ADC1_STARTUP	(((AT91_ADC1_CLOCK+399999)/400000)-1)
#endif

#if AT91_ADC1_RESOLUTION == 8
	#define AT91_ADC1_MAINMODE		(((AT91_ADC1_SHTM & 0x0F) << 24) | ((AT91_ADC1_STARTUP & 0x7F) << 16) | ((AT91_ADC1_PRESCALE & 0xFF) << 8) | AT91C_ADC_LOWRES_8_BIT)
#else
	#define AT91_ADC1_MAINMODE		(((AT91_ADC1_SHTM & 0x0F) << 24) | ((AT91_ADC1_STARTUP & 0x7F) << 16) | ((AT91_ADC1_PRESCALE & 0xFF) << 8) | AT91C_ADC_LOWRES_10_BIT)
#endif

#if AT91_ADC1_TIMER < 0 || AT91_ADC1_TIMER > 2
	#error "Unknown Timer specified for ADC1"
#endif

/*===========================================================================*/
/* Driver exported variables.                                                */
/*===========================================================================*/

#if !ADC_USE_ADC1
	#error "You must specify ADC_USE_ADC1 if you have specified HAL_USE_ADC"
#endif

/** @brief ADC1 driver identifier.*/
ADCDriver ADCD1;

/*===========================================================================*/
/* Driver local variables.                                                   */
/*===========================================================================*/

#define ADCReg1		((AT91S_ADC *)AT91C_ADC_CR)

#if AT91_ADC1_MAINMODE == 2
	#define ADCTimer1				((AT91S_TC *)AT91C_TC2_CCR)
	#define AT91_ADC1_TIMERMODE		AT91C_ADC_TRGSEL_TIOA2
	#define AT91_ADC1_TIMERID		AT91C_ID_TC2
#elif AT91_ADC1_MAINMODE == 1
	#define ADCTimer1				((AT91S_TC *)AT91C_TC1_CCR)
	#define AT91_ADC1_TIMERMODE		AT91C_ADC_TRGSEL_TIOA1
	#define AT91_ADC1_TIMERID		AT91C_ID_TC1
#else
	#define ADCTimer1				((AT91S_TC *)AT91C_TC0_CCR)
	#define AT91_ADC1_TIMERMODE		AT91C_ADC_TRGSEL_TIOA0
	#define AT91_ADC1_TIMERID		AT91C_ID_TC0
#endif

/*===========================================================================*/
/* Driver local functions.                                                   */
/*===========================================================================*/

#define adc_sleep()				ADCReg1->ADC_MR = (AT91_ADC1_MAINMODE | AT91C_ADC_SLEEP_MODE | AT91C_ADC_TRGEN_DIS)
#define adc_wake()				ADCReg1->ADC_MR = (AT91_ADC1_MAINMODE | AT91C_ADC_SLEEP_NORMAL_MODE | AT91C_ADC_TRGEN_DIS)
#define adc_disable()			{																\
									ADCReg1->ADC_IDR = 0xFFFFFFFF;								\
									ADCReg1->ADC_PTCR = AT91C_PDC_RXTDIS | AT91C_PDC_TXTDIS;	\
									adc_wake();													\
									ADCReg1->ADC_CHDR = 0xFF;									\
								}
#define adc_clrint()			{																\
									uint32_t	isr, dummy;										\
																								\
									isr = ADCReg1->ADC_SR;										\
									if ((isr & AT91C_ADC_DRDY)) dummy = ADCReg1->ADC_LCDR;		\
									if ((isr & AT91C_ADC_EOC0)) dummy = ADCReg1->ADC_CDR0;		\
									if ((isr & AT91C_ADC_EOC1)) dummy = ADCReg1->ADC_CDR1;		\
									if ((isr & AT91C_ADC_EOC2)) dummy = ADCReg1->ADC_CDR2;		\
									if ((isr & AT91C_ADC_EOC3)) dummy = ADCReg1->ADC_CDR3;		\
									if ((isr & AT91C_ADC_EOC4)) dummy = ADCReg1->ADC_CDR4;		\
									if ((isr & AT91C_ADC_EOC5)) dummy = ADCReg1->ADC_CDR5;		\
									if ((isr & AT91C_ADC_EOC6)) dummy = ADCReg1->ADC_CDR6;		\
									if ((isr & AT91C_ADC_EOC7)) dummy = ADCReg1->ADC_CDR7;		\
								}
#define adc_stop()				{																\
									adc_disable();												\
									adc_clrint();												\
								}

/**
 * We must keep stack usage to a minimum - the default AT91SAM7 isr stack size is very small.
 * We sacrifice some speed and code size in order to achieve this by accessing the structure
 * and registers directly rather than through the passed in pointers. This works because the
 * AT91SAM7 supports only a single ADC device (although with 8 channels).
 */
static void handleint(void) {
	uint32_t	isr;

	isr = ADCReg1->ADC_SR;

	if (ADCD1.grpp) {

		/* ADC overflow condition, this could happen only if the DMA is unable to read data fast enough.*/
		if ((isr & AT91C_ADC_GOVRE)) {
			_adc_isr_error_code(&ADCD1, ADC_ERR_OVERFLOW);

		/* Transfer complete processing.*/
		} else if ((isr & AT91C_ADC_RXBUFF)) {
			if (ADCD1.grpp->circular) {
				/* setup the DMA again */
				ADCReg1->ADC_RPR = (uint32_t)ADCD1.samples;
				if (ADCD1.depth <= 1) {
					ADCReg1->ADC_RCR = ADCD1.grpp->num_channels;
					ADCReg1->ADC_RNPR = 0;
					ADCReg1->ADC_RNCR = 0;
				} else {
					ADCReg1->ADC_RCR = ADCD1.depth/2 * ADCD1.grpp->num_channels;
					ADCReg1->ADC_RNPR = (uint32_t)(ADCD1.samples + (ADCD1.depth/2 * ADCD1.grpp->num_channels));
					ADCReg1->ADC_RNCR = (ADCD1.depth - ADCD1.depth/2) * ADCD1.grpp->num_channels;
				}
				ADCReg1->ADC_PTCR = AT91C_PDC_RXTEN;			// DMA enabled
			}
			_adc_isr_full_code(&ADCD1);

		/* Half transfer processing.*/
		} else if ((isr & AT91C_ADC_ENDRX)) {
			_adc_isr_half_code(&ADCD1);
		}

	} else {
		/* Spurious interrupt - Make sure it doesn't happen again */
		adc_disable();
	}
}

/*===========================================================================*/
/* Driver interrupt handlers.                                                */
/*===========================================================================*/

/**
 * @brief   ADC interrupt handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(ADC_IRQHandler) {
	CH_IRQ_PROLOGUE();

	handleint();

	AT91C_BASE_AIC->AIC_EOICR = 0;
	CH_IRQ_EPILOGUE();
}

/*===========================================================================*/
/* Driver exported functions.                                                */
/*===========================================================================*/

/**
 * @brief   Low level ADC driver initialization.
 *
 * @notapi
 */
void adc_lld_init(void) {
	/* Turn on ADC in the power management controller */
	AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_ADC);

	/* Driver object initialization.*/
	adcObjectInit(&ADCD1);

	ADCReg1->ADC_CR = 0;				// 0 or AT91C_ADC_SWRST if you want to do a ADC reset
	adc_stop();
	adc_sleep();

	/* Setup interrupt handler */
	AIC_ConfigureIT(AT91C_ID_ADC,
		  AT91C_AIC_SRCTYPE_HIGH_LEVEL | AT91_ADC_IRQ_PRIORITY,
		  ADC_IRQHandler);
	AIC_EnableIT(AT91C_ID_ADC);
}

/**
 * @brief   Configures and activates the ADC peripheral.
 *
 * @param[in] adcp      pointer to the @p ADCDriver object
 *
 * @notapi
 */
void adc_lld_start(ADCDriver *adcp) {

	/* If in stopped state then wake up the ADC */
	if (adcp->state == ADC_STOP) {

    	/* Take it out of sleep mode */
    	/* We could stay in sleep mode provided total conversion rate < 44khz but we can't guarantee that here */
    	adc_wake();

    	/* TODO: We really should perform a conversion here just to ensure that we are out of sleep mode */
    }
}

/**
 * @brief   Deactivates the ADC peripheral.
 *
 * @param[in] adcp      pointer to the @p ADCDriver object
 *
 * @notapi
 */
void adc_lld_stop(ADCDriver *adcp) {
	if (adcp->state != ADC_READY) {
		adc_stop();
    	adc_sleep();
	}
}

/**
 * @brief   Starts an ADC conversion.
 *
 * @param[in] adcp      pointer to the @p ADCDriver object
 *
 * @notapi
 */
void adc_lld_start_conversion(ADCDriver *adcp) {
	uint32_t			i;

	/* Make sure everything is stopped first */
	adc_stop();

	/* Safety check the trigger value */
	switch(ADCD1.grpp->trigger & ~ADC_TRIGGER_SOFTWARE) {
	case ADC_TRIGGER_TIMER:
	case ADC_TRIGGER_EXTERNAL:
		break;
	default:
		((ADCConversionGroup *)ADCD1.grpp)->trigger = ADC_TRIGGER_SOFTWARE;
		ADCD1.depth = 1;
		((ADCConversionGroup *)ADCD1.grpp)->circular = 0;
		break;
	}

	/* Count the real number of activated channels in case the user got it wrong */
	((ADCConversionGroup *)ADCD1.grpp)->num_channels = 0;
	for(i=1; i < 0x100; i <<= 1) {
		if ((ADCD1.grpp->channelselects & i))
			((ADCConversionGroup *)ADCD1.grpp)->num_channels++;
	}

	/* Set the channels */
	ADCReg1->ADC_CHER = ADCD1.grpp->channelselects;

	/* Set up the DMA */
	ADCReg1->ADC_RPR = (uint32_t)ADCD1.samples;
	if (adcp->depth <= 1) {
		ADCReg1->ADC_RCR = ADCD1.grpp->num_channels;
		ADCReg1->ADC_RNPR = 0;
		ADCReg1->ADC_RNCR = 0;
	} else {
		ADCReg1->ADC_RCR = ADCD1.depth/2 * ADCD1.grpp->num_channels;
		ADCReg1->ADC_RNPR = (uint32_t)(ADCD1.samples + (ADCD1.depth/2 * ADCD1.grpp->num_channels));
		ADCReg1->ADC_RNCR = (ADCD1.depth - ADCD1.depth/2) * ADCD1.grpp->num_channels;
	}
	ADCReg1->ADC_PTCR = AT91C_PDC_RXTEN;

	/* Set up interrupts */
	ADCReg1->ADC_IER = AT91C_ADC_GOVRE | AT91C_ADC_ENDRX | AT91C_ADC_RXBUFF;

	/* Set the trigger */
	switch(ADCD1.grpp->trigger & ~ADC_TRIGGER_SOFTWARE) {
	case ADC_TRIGGER_TIMER:
		// Set up the timer if ADCD1.grpp->frequency != 0
		if (ADCD1.grpp->frequency) {
			/* Turn on Timer in the power management controller */
			AT91C_BASE_PMC->PMC_PCER = (1 << AT91_ADC1_TIMERID);

		    /* Disable the clock and the interrupts */
			ADCTimer1->TC_CCR = AT91C_TC_CLKDIS;
			ADCTimer1->TC_IDR = 0xFFFFFFFF;

		    /* Set the Mode of the Timer Counter and calculate the period */
			i = (MCK/2)/ADCD1.grpp->frequency;
			if (i < (0x10000<<0)) {
				ADCTimer1->TC_CMR = (AT91C_TC_ASWTRG_CLEAR | AT91C_TC_ACPC_CLEAR | AT91C_TC_ACPA_SET | AT91C_TC_LDRA_RISING |
				                        AT91C_TC_WAVE  | AT91C_TC_WAVESEL_UP_AUTO | AT91C_TC_CLKS_TIMER_DIV1_CLOCK);
			} else if (i < (0x10000<<2)) {
				i >>= 2;
				ADCTimer1->TC_CMR = (AT91C_TC_ASWTRG_CLEAR | AT91C_TC_ACPC_CLEAR | AT91C_TC_ACPA_SET | AT91C_TC_LDRA_RISING |
				                        AT91C_TC_WAVE  | AT91C_TC_WAVESEL_UP_AUTO | AT91C_TC_CLKS_TIMER_DIV2_CLOCK);
			} else if (i < (0x10000<<4)) {
				i >>= 4;
				ADCTimer1->TC_CMR = (AT91C_TC_ASWTRG_CLEAR | AT91C_TC_ACPC_CLEAR | AT91C_TC_ACPA_SET | AT91C_TC_LDRA_RISING |
				                        AT91C_TC_WAVE  | AT91C_TC_WAVESEL_UP_AUTO | AT91C_TC_CLKS_TIMER_DIV3_CLOCK);
			} else if (i < (0x10000<<6)) {
				i >>= 6;
				ADCTimer1->TC_CMR = (AT91C_TC_ASWTRG_CLEAR | AT91C_TC_ACPC_CLEAR | AT91C_TC_ACPA_SET | AT91C_TC_LDRA_RISING |
				                        AT91C_TC_WAVE  | AT91C_TC_WAVESEL_UP_AUTO | AT91C_TC_CLKS_TIMER_DIV4_CLOCK);
			} else {
				i >>= 9;
				ADCTimer1->TC_CMR = (AT91C_TC_ASWTRG_CLEAR | AT91C_TC_ACPC_CLEAR | AT91C_TC_ACPA_SET | AT91C_TC_LDRA_RISING |
				                        AT91C_TC_WAVE  | AT91C_TC_WAVESEL_UP_AUTO | AT91C_TC_CLKS_TIMER_DIV5_CLOCK);
			}

		    /* RC is the period, RC-RA is the pulse width (in this case = 1) */
			ADCTimer1->TC_RC = i;
			ADCTimer1->TC_RA = i - 1;

			/* Start the timer counter */
			ADCTimer1->TC_CCR = (AT91C_TC_CLKEN |AT91C_TC_SWTRG);
		}

		ADCReg1->ADC_MR = AT91_ADC1_MAINMODE | AT91C_ADC_SLEEP_NORMAL_MODE | AT91C_ADC_TRGEN_EN | AT91_ADC1_TIMERMODE;
		break;

	case ADC_TRIGGER_EXTERNAL:
		/* Make sure the ADTRG pin is set as an input - assume pull-ups etc have already been set */
		#if (SAM7_PLATFORM == SAM7S64) || (SAM7_PLATFORM == SAM7S128) || (SAM7_PLATFORM == SAM7S256) || (SAM7_PLATFORM == SAM7S512)
			AT91C_BASE_PIOA->PIO_ODR	= AT91C_PA8_ADTRG;
		#elif (SAM7_PLATFORM == SAM7X128) || (SAM7_PLATFORM == SAM7X256) || (SAM7_PLATFORM == SAM7X512)
			AT91C_BASE_PIOB->PIO_ODR	= AT91C_PB18_ADTRG;
		#endif
    	ADCReg1->ADC_MR = AT91_ADC1_MAINMODE | AT91C_ADC_SLEEP_NORMAL_MODE | AT91C_ADC_TRGEN_EN | AT91C_ADC_TRGSEL_EXT;
    	break;

	default:
    	ADCReg1->ADC_MR = AT91_ADC1_MAINMODE | AT91C_ADC_SLEEP_NORMAL_MODE | AT91C_ADC_TRGEN_DIS;
    	break;
	}

	/* Manually start a conversion if we need to */
	if (ADCD1.grpp->trigger & ADC_TRIGGER_SOFTWARE)
    	ADCReg1->ADC_CR = AT91C_ADC_START;
}

/**
 * @brief   Stops an ongoing conversion.
 *
 * @param[in] adcp      pointer to the @p ADCDriver object
 *
 * @notapi
 */
void adc_lld_stop_conversion(ADCDriver *adcp) {
	(void) adcp;
	adc_stop();
}

#endif /* HAL_USE_ADC */

/** @} */