/* counter.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. * * }}} */ /** Define to 1 to reverse the left counter. */ #define COUNTER_REVERSE_LEFT 1 /** Define to 1 to reverse the right counter. */ #define COUNTER_REVERSE_RIGHT 0 /** Forward and reverse counter values. */ static uint8_t counter_left_frw, counter_left_rev, counter_right_frw, counter_right_rev; /** Last TCNT values. */ static uint8_t counter_left_old, counter_right_old; /** Overall counter values. */ static uint16_t counter_left, counter_right; /** Counter differences since last update. * Maximum of 9 significant bits, sign included. */ static int16_t counter_left_diff, counter_right_diff; /* +AutoDec */ /** Initialize the counters. */ static inline void counter_init (void); /** Poll counters, should be called as often as possible. */ static inline void counter_poll (void); /** Update overall counter values and compute diffs. */ static inline void counter_update (void); /** Restart counting. */ static inline void counter_restart (void); /* -AutoDec */ /** Initialize the counters. */ static inline void counter_init (void) { /* Left counter. */ /* External, rising edge. */ TCCR2 = regv (FOC2, WGM20, COM21, COM20, WGM21, CS22, CS21, CS20, 0, 0, 0, 0, 0, 1, 1, 1); /* Right counter. */ /* Normal counter. */ TCCR3A = 0; /* External, rising edge. */ TCCR3B = regv (ICNC3, ICES3, 5, WGM33, WGM32, CS32, CS31, CS30, 0, 0, 0, 0, 0, 1, 1, 1); /* Begin with safe values. */ counter_restart (); } /** Poll counters, should be called as often as possible. */ static inline void counter_poll (void) { uint8_t c; /* Read left counter. */ c = TCNT2; #if COUNTER_REVERSE_LEFT == 0 if (PINE & _BV (4)) #else if (!(PINE & _BV (4))) #endif { PORTD &= ~0x40; counter_left_frw += c - counter_left_old; } else { PORTD |= 0x40; counter_left_rev += c - counter_left_old; } counter_left_old = c; /* Read right counter. */ c = TCNT3L; #if COUNTER_REVERSE_RIGHT == 0 if (PINE & _BV (5)) #else if (!(PINE & _BV (5))) #endif { PORTD &= ~0x20; counter_right_frw += c - counter_right_old; } else { PORTD |= 0x20; counter_right_rev += c - counter_right_old; } counter_right_old = c; } /** Update overall counter values and compute diffs. */ static inline void counter_update (void) { counter_left_diff = counter_left_frw; counter_left_frw = 0; counter_left_diff -= counter_left_rev; counter_left_rev = 0; counter_left += counter_left_diff; counter_right_diff = counter_right_frw; counter_right_frw = 0; counter_right_diff -= counter_right_rev; counter_right_rev = 0; counter_right += counter_right_diff; } /** Restart counting. */ static inline void counter_restart (void) { counter_left_frw = 0; counter_left_rev = 0; counter_left_old = TCNT2; counter_right_frw = 0; counter_right_rev = 0; counter_right_old = TCNT3L; }