dac.c File Reference

---

Detailed Description

AVR32 ABDAC example application.

Application note:

AVR32120 - AVR32 ABDAC audio bitstream DAC driver example

Documentation

For comprehensive code documentation, supported compilers, compiler settings and supported devices see readme.html.

Author:

Atmel Corporation: http://www.atmel.com
Support email: avr32@atmel.com

Revision

506

Date

2007-05-21 20:00:05 +0200 (Mon, 21 May 2007)

Definition in file dac.c.

#include "dac.h"

Include dependency graph for dac.c:

Go to the source code of this file.

Functions
void	abdac_disable (volatile avr32_abdac_t *abdac)
	Disables the ABDAC modules.
void	abdac_enable (volatile avr32_abdac_t *abdac)
	Enables the ABDAC modules.
unsigned long	abdac_get_dac_hz (volatile avr32_abdac_t *abdac, const unsigned long bus_hz)
	Get the DAC sample rate in Hz.
unsigned long	abdac_set_dac_hz (volatile avr32_abdac_t *abdac, const unsigned long bus_hz, const unsigned long dac_hz)
	Set the DAC sample rate in Hz.
int	abdac_sink (volatile avr32_abdac_t *abdac, const unsigned short ch0, const unsigned short ch1)
	Send data to the ABDAC.

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Function Documentation

void abdac_disable

(

volatile avr32_abdac_t *

abdac

)

Disables the ABDAC modules.

This function disables the abdac module.

Parameters:

abdac

Pointer to the base register of the ABDAC module.

Definition at line 69 of file dac.c.

References ABDAC_BIT, and GCLK_BIT.

Referenced by main().

{
    volatile avr32_pm_t *pm = &AVR32_PM;
    abdac->cr &= ~ABDAC_BIT(CR_EN);
    pm->gcctrl[ABDAC_GCLK] &= ~GCLK_BIT(CEN);
}

void abdac_enable

(

volatile avr32_abdac_t *

abdac

)

Enables the ABDAC modules.

This function enables the abdac module.

Parameters:

abdac

Pointer to the base register of the ABDAC module.

Definition at line 56 of file dac.c.

References ABDAC_BIT, and GCLK_BIT.

Referenced by main().

{
    volatile avr32_pm_t *pm = &AVR32_PM;
    pm->gcctrl[ABDAC_GCLK] |= GCLK_BIT(CEN);
    abdac->cr |= ABDAC_BIT(CR_EN);
}

unsigned long abdac_get_dac_hz	(	volatile avr32_abdac_t *	abdac,
		const unsigned long	bus_hz
	)

Get the DAC sample rate in Hz.

This function gets the DAC sample rate in Hz from a given peripheral bus speed.

Parameters:

	abdac	Pointer to the base register of the ABDAC module.
	bus_hz	Speed of peripheral bus in Hz.

Returns:

ABDAC sample rate.

Definition at line 121 of file dac.c.

References GCLK_BFEXT, and GCLK_BIT.

{
    volatile avr32_pm_t *pm = &AVR32_PM;
    unsigned short div = 0;

    if (pm->gcctrl[ABDAC_GCLK] & GCLK_BIT(DIVEN)) {
        div = 2 * (GCLK_BFEXT(DIV, pm->gcctrl[ABDAC_GCLK]) + 1);
    }

    return (bus_hz / div);
}

unsigned long abdac_set_dac_hz	(	volatile avr32_abdac_t *	abdac,
		const unsigned long	bus_hz,
		const unsigned long	dac_hz
	)

Set the DAC sample rate in Hz.

This function sets the DAC sample rate in Hz from a given peripheral bus speed. The playback data must match this sample speed.

Parameters:

	abdac	Pointer to the base register of the ABDAC module.
	bus_hz	Speed of peripheral bus in Hz.
	dac_hz	Wanted sample rate of ABDAC in Hz.

Returns:

ABDAC sample rate or -EINVAL on error.

Definition at line 87 of file dac.c.

References EINVAL, GCLK_BF, and GCLK_BIT.

Referenced by main().

{
    volatile avr32_pm_t *pm = &AVR32_PM;
    unsigned short div;

    if (bus_hz < (256 * dac_hz)) {
        return -EINVAL;
    }

    div = bus_hz / (256 * dac_hz);

    /* div must be a power of 2. */
    div = (div + 1) & ~1UL;

    if (div > 2) {
        pm->gcctrl[ABDAC_GCLK] = GCLK_BIT(DIVEN) | GCLK_BF(DIV, ((div / 2) - 1));
    } else {
        pm->gcctrl[ABDAC_GCLK] = GCLK_BIT(DIVEN);
    }

    return (bus_hz / (256 * div));
}

int abdac_sink	(	volatile avr32_abdac_t *	abdac,
		const unsigned short	ch0,
		const unsigned short	ch1
	)

Send data to the ABDAC.

This function sends data to the two channels provided by the ABDAC peripheral.

Parameters:

	abdac	Pointer to the base register of the ABDAC module.
	ch0	16-bit unsigned value for channel 0.
	ch1	16-bit unsigned value for channel 1.

Returns:

0 on success or -ETIMEOUT on timeout error.

Definition at line 145 of file dac.c.

References ABDAC_BF, ABDAC_BIT, and ETIMEOUT.

Referenced by main().

{
    volatile unsigned long timeout = ABDAC_TIMEOUT;

    do {
    } while (!(abdac->isr & ABDAC_BIT(ISR_TX_READY)) && timeout--);

    if (0 == timeout) {
        return -ETIMEOUT;
    }

    abdac->sdr = ABDAC_BF(SDR_CHANNEL0, ch0) | ABDAC_BF(SDR_CHANNEL1, ch1);

    return 0;
}