aversive_10-03-12/modules/hardware/pwm_ng/pwm_ng.c

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/*  
 *  Copyright Droids Corporation, Microb Technology, Eirbot (2005)
 * 
 *  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 2 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
 *
 *  Copyright Droids-corporation - Olivier MATZ - 2009
 */
#include <string.h>

#include <aversive.h>
#include <aversive/parts.h>
#include <aversive/timers.h>

#include "pwm_ng.h"

/* value to be used for limiting inputs */
#define PWM_SIGNIFICANT_BITS 12
#define PWM_MAX ((1<< PWM_SIGNIFICANT_BITS)-1)
#define PWM_MIN (-PWM_MAX)

#define PWM_NG_TYPE_8   0
#define PWM_NG_TYPE_16  1

#define PWM_NG_NBITS_8   0
#define PWM_NG_NBITS_9   1
#define PWM_NG_NBITS_10  2

void pwm_ng_init(struct pwm_ng *pwm, uint8_t timer_nbits, 
                 uint8_t pwm_nbits, uint8_t pwm_mode,
                 volatile void *ocrn, 
                 uint8_t com0, volatile uint8_t *tccrn,
                 volatile uint8_t *pwm_port, uint8_t pwm_bit,
                 volatile uint8_t *sign_port, uint8_t sign_bit)
{
        memset(pwm, 0, sizeof(*pwm));

        if (timer_nbits == 8) {
                pwm->type = PWM_NG_TYPE_8;
                pwm->u.ocr8 = ocrn;
                *pwm->u.ocr8 = 0;
        }
        else {
                pwm->type = PWM_NG_TYPE_16;
                pwm->u.ocr16 = ocrn;
                *pwm->u.ocr16 = 0;
        }
        switch (pwm_nbits) {
        case 9:
                pwm->nbits = PWM_NG_NBITS_9;
                break;
        case 10:
                pwm->nbits = PWM_NG_NBITS_10;
                break;
        case 8:
        default:
                pwm->nbits = PWM_NG_NBITS_8;
                break;
        }
        pwm->mode = pwm_mode;

        *tccrn &= ~(0x03 << com0);
        if (pwm_mode & PWM_NG_MODE_REVERSE)
                *tccrn |= (0x01 << com0);
        else
                *tccrn |= (0x02 << com0);
        
        DDR(*pwm_port) |= (1 << pwm_bit);

        if ((pwm_mode & PWM_NG_MODE_SIGNED) && (sign_port))
                DDR(*sign_port) |= (1 << sign_bit);
        pwm->sign_port = sign_port;
        pwm->sign_bit = sign_bit;
}

static inline void pwm_sign_set(struct pwm_ng *pwm)
{
        if (pwm->mode & PWM_NG_MODE_SIGN_INVERTED)
                *pwm->sign_port &= ~(1 << pwm->sign_bit);
        else
                *pwm->sign_port |= (1 << pwm->sign_bit);
}

static inline void pwm_sign_reset(struct pwm_ng *pwm)
{
        if (pwm->mode &PWM_NG_MODE_SIGN_INVERTED)
                *pwm->sign_port |= (1 << pwm->sign_bit);
        else
                *pwm->sign_port &= ~(1 << pwm->sign_bit);
}

static inline int32_t pwm_invert_value(struct pwm_ng *pwm, int32_t value)
{
        if (pwm->mode & PWM_NG_MODE_SPECIAL_SIGN)
                return value & PWM_MAX;
        else
                return -value;
}

#include <stdio.h>
void pwm_ng_set(void *data, int32_t value)
{
        struct pwm_ng *pwm = data;
        uint8_t nbits = 8 + pwm->nbits;

        MAX(value, PWM_MAX);
        if (pwm->mode & PWM_NG_MODE_SIGNED) {
                MIN(value, PWM_MIN);
                if (value < 0) {
                        pwm_sign_set(pwm);
                        value = pwm_invert_value(pwm, value);
                }
                else {
                        pwm_sign_reset(pwm);
                }
        }
        else {
                MIN(value, 0);
        }
        if (pwm->type == PWM_NG_TYPE_8)
                *pwm->u.ocr8 = (uint8_t) (value >> (PWM_SIGNIFICANT_BITS - 8));
        else
                *pwm->u.ocr16 = (value >> (PWM_SIGNIFICANT_BITS - nbits));
}

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