pios_annuncdac.c

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/*
 * This program 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.
 *
 * This program 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, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

/* Project Includes */
#include <pios.h>

#if defined(PIOS_INCLUDE_DAC_ANNUNCIATOR)
#include <pios_annuncdac.h>

#include <misc_math.h>

struct annuncdac_dev_s {
        uint32_t magic;
#define ANNUNCDAC_DEV_MAGIC 0x43414441  // 'ADAC'

        dac_dev_t dac;

        volatile bool value;

        uint8_t history;
        uint16_t phase_accum;

        pios_com_callback tx_out_cb;
        uintptr_t tx_out_context;

        bool tx_running;
};

static bool PIOS_ANNUNCDAC_cb(void *ctx, uint16_t *buf, int len);

static bool PIOS_ANNUNCDAC_validate(annuncdac_dev_t annuncdac_dev)
{
        return (annuncdac_dev->magic == ANNUNCDAC_DEV_MAGIC);
}

int32_t PIOS_ANNUNCDAC_Init(annuncdac_dev_t *annuncdac_id, dac_dev_t dac)
{
        PIOS_DEBUG_Assert(annuncdac_id);
        PIOS_DEBUG_Assert(cfg);

        annuncdac_dev_t annuncdac_dev = PIOS_malloc(sizeof(*annuncdac_dev));

        if (!annuncdac_dev) return -1;

        *annuncdac_dev = (struct annuncdac_dev_s) { 
                .magic = ANNUNCDAC_DEV_MAGIC,
                .dac = dac,
        };

        *annuncdac_id = annuncdac_dev;

        PIOS_DAC_install_callback(annuncdac_dev->dac, 100, 
                        PIOS_ANNUNCDAC_cb, annuncdac_dev);

        return 0;
}

static inline void FillBuf(annuncdac_dev_t dev, uint16_t *buf, int len,
                uint16_t freq, int start_mag, int stop_mag) {
        int mag_span = stop_mag - start_mag;

        for (int i=0; i < len; i++) {
                dev->phase_accum += freq;

                int magnitude = (mag_span * i + len / 2) / len;
                magnitude += start_mag;

                uint16_t result = 32768 +
                        (magnitude * sin_approx(dev->phase_accum >> 1) >> 2);

                buf[i] = result & 0xFFF0;
        }
}

#define ANNUNC_FREQ 1911        /* 65536 / (24000Hz / 700Hz) =~ 1911 */
static bool PIOS_ANNUNCDAC_cb(void *ctx, uint16_t *buf, int len)
{
        annuncdac_dev_t dev = ctx;
        PIOS_Assert(PIOS_ANNUNCDAC_validate(dev));

        dev->history <<= 1;

        if (dev->value) {
                dev->history |= 1;
        }

        switch (dev->history & 3) {
                case 0:
                        /* Off, has been off */
                        for (int i = 0; i < len; i++) {
                                buf[i] = 32768;
                        }
                        return true;
                case 1:
                        FillBuf(dev, buf, len, ANNUNC_FREQ, 1, 6);
                        break;
                case 2:
                        /* Going off */
                        FillBuf(dev, buf, len, ANNUNC_FREQ, 6, 1);
                        break;
                case 3:
                        /* Steady state */
                        FillBuf(dev, buf, len, ANNUNC_FREQ, 6, 6);
                        break;
        }

        return true;
}

void PIOS_ANNUNCDAC_SetValue(annuncdac_dev_t dev, bool active, bool value)
{
        (void) active;

        PIOS_Assert(PIOS_ANNUNCDAC_validate(dev));

        dev->value = value;
}

#endif /* PIOS_INCLUDE_DAC_ANNUNCIATOR */