/* pwm.c */ /* asserv - Position & speed motor control on a ATmega128. {{{ * * Copyright (C) 2004 Nicolas Schodet * * Robot APB Team/Efrei 2005. * Web: http://assos.efrei.fr/robot/ * Email: robot AT efrei DOT fr * * 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. * * }}} */ /** PWM values. */ int16_t pwm_left, pwm_right; /* +AutoDec */ /** Initialise PWM generator. */ static inline void pwm_init (void); /** Preprocess a PWM value before sending it to hardware. */ static inline uint8_t pwm_preproc (uint16_t v); /** Update the hardware PWM values. */ static inline void pwm_update (void); /* -AutoDec */ /** Initialise PWM generator. */ static inline void pwm_init (void) { /* Phase correct PWM, TOP = 0xff, OC1B & OC1C with positive logic. f_IO without prescaler. Fpwm = f_IO / (2 * prescaler * TOP) = 28912 Hz. */ TCCR1A = regv (COM1A1, COM1A0, COM1B1, COM1B0, COM1C1, COM1C0, WGM11, WGM10, 0, 0, 1, 0, 1, 0, 0, 1); TCCR1B = regv (ICNC1, ICES1, 5, WGM13, WGM12, CS12, CS11, CS10, 0, 0, 0, 0, 0, 0, 0, 1); /* Enable pwm and direction outputs in DDRB. */ DDRB |= _BV (7) | _BV (6) | _BV (3) | _BV (2); } /** Preprocess a PWM value before sending it to hardware. */ static inline uint8_t pwm_preproc (uint16_t v) { // This is a try to correct the optocoupler problem... //v += 0x10; if (v > 255) return 255; else return v; } /** Update the hardware PWM values. */ static inline void pwm_update (void) { /* Set left PWM. */ if (pwm_left == 0) { OCR1B = 0; } else if (pwm_left < 0) { PORTB |= _BV (2); OCR1B = pwm_preproc (-pwm_left); } else { PORTB &= ~_BV (2); OCR1B = pwm_preproc (pwm_left); } /* Set right PWM. */ if (pwm_right == 0) { OCR1C = 0; } else if (pwm_right < 0) { PORTB &= ~_BV (3); OCR1C = pwm_preproc (-pwm_right); } else { PORTB |= _BV (3); OCR1C = pwm_preproc (pwm_right); } }