#ifndef utils_h #define utils_h // utils.h // n.avr.utils - AVR utilities module. {{{ // // Copyright (C) 2004 Nicolas Schodet // // 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. // // Contact : // Web: http://perso.efrei.fr/~schodet/ // Email: // }}} #include "avrconfig.h" #include #include /** Delay in ns. Do not call this macro with a variable parameter. If you * want a variable delay, prefer looping over a fixed delay. * * Maximum delay is about 3.3s at 20MHz. * * Should be a inline function, but GCC do not inline like I want. */ #define delay_ns(ns_) \ do { \ static const uint32_t ns = (ns_); \ static const uint32_t t = 1000000000lu / AC_FREQ; \ static const uint32_t t8 = t * 255 * 3; \ static const uint32_t t16 = t * 65535 * 4; \ if (ns <= t) \ { \ /* Delay shorter than 1 instruction. */ \ asm volatile ("nop" : :); \ } \ else if (ns <= t * 2) \ { \ /* Delay shorter than 2 instruction. */ \ asm volatile ("nop\n\tnop" : :); \ } \ else if (ns <= t * 3) \ { \ /* Delay shorter than 3 instruction. */ \ asm volatile ("nop\n\tnop\n\tnop" : :); \ } \ else if (ns <= t8) \ { \ static const uint8_t b = (uint8_t) ((ns + t * 3 - 1) / (t * 3)); \ _delay_loop_1 (b); \ } \ else if (ns <= t16) \ { \ static const uint16_t b = (uint16_t) ((ns + t * 4 - 1) / (t * 4)); \ _delay_loop_2 (b); \ } \ else \ { \ static const uint8_t ob = (uint8_t) ((ns + t16 - 1) / t16); \ static const uint16_t ib = (uint16_t) ((ns / ob + t * 4 - 1) \ / (t * 4)); \ uint8_t i; \ i = ob; \ while (i--) \ _delay_loop_2 (ib); \ } \ } while (0) /** Shortcut for delay_ns (us * 1000). */ #define delay_us(us) delay_ns ((us) * 1000) /** Shortcut for delay_ns (ms * 1000 * 1000). */ #define delay_ms(ms) delay_ns ((ms) * 1000 * 1000) /** Delay in seconds. Maximum of 256 seconds. */ extern inline void delay_s (uint8_t s) { while (s--) delay_ns (1000000000); } #endif // utils_h