/* avrcounter-port-two.c - Double encoder, port output. */ /* avrcounter - Incremental encoder counter. {{{ * * Copyright (C) 2007 Nicolas Schodet * * Robot APB Team 2008. * Web: http://apbteam.org/ * Email: team AT apbteam DOT org * * 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. * * }}} */ #include int main (void) { uint8_t count0 = 0, count1 = 0; uint8_t state0 = 0, state1 = 0; /* Encoder signals: * ____----____----____---- * __----____----____----__ */ static const int8_t inc[] = { 0, /* 00 -> 00 */ +1, /* 00 -> 01 */ -1, /* 00 -> 10 */ 0, /* 00 -> 11, missed! */ -1, /* 01 -> 00 */ 0, /* 01 -> 01 */ 0, /* 01 -> 10, missed! */ +1, /* 01 -> 11 */ +1, /* 10 -> 00 */ 0, /* 10 -> 01, missed! */ 0, /* 10 -> 10 */ -1, /* 10 -> 11 */ 0, /* 11 -> 00, missed! */ -1, /* 11 -> 01 */ +1, /* 11 -> 10 */ 0, /* 11 -> 11 */ }; DDRD = 0xff; while (1) { state0 = (state0 << 2) | (PINC & 0x03); count0 += inc[state0]; state1 = (state1 << 2) | ((PINC >> 2) & 0x03); count1 += inc[state1]; PORTD = (PINB & 1) ? count1 : count0; } }