Mercurial > ~darius > hgwebdir.cgi > avr
view 1wire.c @ 26:350e8655cbb7
- Remove some #if'd out code.
- Use STRING_DESCRIPTOR types instead of rolling one for each type of
string.
- Fix comment typo.
author | darius |
---|---|
date | Tue, 13 Dec 2005 10:53:48 +1030 |
parents | bd792ebf813d |
children | 02b67e09ca12 |
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/* * Various 1 wire routines * Search routine is copied from the Dallas owpd library with mods * available from here http://www.ibutton.com/software/1wire/wirekit.html * * $Id$ * * Copyright (c) 2004 * Daniel O'Connor <darius@dons.net.au>. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include <stdio.h> #include <avr/io.h> #include <avr/pgmspace.h> #include <util/delay.h> #include "1wire.h" #include "1wire-delay.h" #if OW_DEBUG void uart_putsP(const char *addr); void uart_puts(const char *addr); void uart_getc(); char uart_putc(char c); #endif static uint8_t OW_LastDevice = 0; static uint8_t OW_LastDiscrepancy = 0; static uint8_t OW_LastFamilyDiscrepancy = 0; static void OWdelay(void) { DELAY_I; } /*----------------------------------------------------------------------------- * Generate a 1-Wire reset, return 0 if presence pulse was found, 1 if it * wasn't, or 2 if the line appears to be being held low. * * * (NOTE: Does not handle alarm presence from DS2404/DS1994) */ uint8_t OWTouchReset(void) { DELAY_G; if (!(OWIREINPORT & _BV(OWIREINPIN))) return 2; OWIREOUTPORT &= ~(_BV(OWIREOUTPIN)); OWIREDDR |= _BV(OWIREOUTPIN); DELAY_H; OWIREDDR &= ~(_BV(OWIREOUTPIN)); DELAY_I; return(OWIREINPORT & _BV(OWIREINPIN) ? 1 : 0); } /*----------------------------------------------------------------------------- * Send a 1-wire write bit. */ void OWWriteBit(uint8_t bit) { OWdelay(); if (bit) { OWIREOUTPORT &= ~(_BV(OWIREOUTPIN)); OWIREDDR |= _BV(OWIREOUTPIN); DELAY_A; OWIREDDR &= ~(_BV(OWIREOUTPIN)); DELAY_B; } else { OWIREOUTPORT &= ~(_BV(OWIREOUTPIN)); OWIREDDR |= _BV(OWIREOUTPIN); DELAY_C; OWIREDDR &= ~(_BV(OWIREOUTPIN)); DELAY_D; } } /*----------------------------------------------------------------------------- * Read a bit from the 1-wire bus and return it. */ uint8_t OWReadBit(void) { OWdelay(); OWIREOUTPORT &= ~(_BV(OWIREOUTPIN)); OWIREDDR |= _BV(OWIREOUTPIN); DELAY_A; OWIREDDR &= ~(_BV(OWIREOUTPIN)); DELAY_E; return(OWIREINPORT & _BV(OWIREINPIN) ? 1 : 0); } /*----------------------------------------------------------------------------- * Write a byte to the 1-wire bus */ void OWWriteByte(uint8_t data) { uint8_t i; /* Send LSB first */ for (i = 0; i < 8; i++) { OWWriteBit(data & 0x01); data >>= 1; } } /*----------------------------------------------------------------------------- * Read a byte from the 1-wire bus */ uint8_t OWReadByte(void) { int i, result = 0; for (i = 0; i < 8; i++) { result >>= 1; if (OWReadBit()) result |= 0x80; } return(result); } /*----------------------------------------------------------------------------- * Write a 1-wire data byte and return the sampled result. */ uint8_t OWTouchByte(uint8_t data) { uint8_t i, result = 0; for (i = 0; i < 8; i++) { result >>= 1; /* If sending a 1 then read a bit, otherwise write a 0 */ if (data & 0x01) { if (OWReadBit()) result |= 0x80; } else OWWriteBit(0); data >>= 1; } return(result); } /*----------------------------------------------------------------------------- * Write a block of bytes to the 1-wire bus and return the sampled result in * the same buffer */ void OWBlock(uint8_t *data, int len) { int i; for (i = 0; i < len; i++) data[i] = OWTouchByte(data[i]); } /*----------------------------------------------------------------------------- * Send a 1 wire command to a device, or all if no ROM ID provided */ void OWSendCmd(uint8_t *ROM, uint8_t cmd) { uint8_t i; OWTouchReset(); if (ROM == NULL) OWWriteByte(OW_SKIP_ROM_CMD); else { OWWriteByte(OW_MATCH_ROM_CMD); for (i = 0; i < 8; i++) OWWriteByte(ROM[i]); } OWWriteByte(cmd); } /*----------------------------------------------------------------------------- * Search algorithm from App note 187 (and 162) * * OWFirst/OWNext return.. * 1 when something is found, * 0 no more modules * -1 if no presence pulse, * -2 if bad CRC, * -3 if bad wiring. */ uint8_t OWFirst(uint8_t *ROM, uint8_t do_reset, uint8_t alarm_only) { /* Reset state */ OW_LastDiscrepancy = 0; OW_LastDevice = 0; OW_LastFamilyDiscrepancy = 0; /* Go looking */ return (OWNext(ROM, do_reset, alarm_only)); } /* Returns 1 when something is found, 0 if nothing left */ uint8_t OWNext(uint8_t *ROM, uint8_t do_reset, uint8_t alarm_only) { uint8_t bit_test, search_direction, bit_number; uint8_t last_zero, rom_byte_number, rom_byte_mask; uint8_t lastcrc8, crcaccum; int8_t next_result; /* Init for search */ bit_number = 1; last_zero = 0; rom_byte_number = 0; rom_byte_mask = 1; next_result = OW_NOMODULES; lastcrc8 = 0; crcaccum = 0; /* if the last call was not the last one */ if (!OW_LastDevice) { /* check if reset first is requested */ if (do_reset) { /* reset the 1-wire * if there are no parts on 1-wire, return 0 */ #if OW_DEBUG uart_putsP(PSTR("Resetting\n\r")); #endif switch (OWTouchReset()) { case 0: break; case 1: /* reset the search */ OW_LastDiscrepancy = 0; OW_LastFamilyDiscrepancy = 0; #if OW_DEBUG uart_putsP(PSTR("No devices on bus\n\r")); #endif return OW_NOPRESENCE; break; case 2: /* reset the search */ OW_LastDiscrepancy = 0; OW_LastFamilyDiscrepancy = 0; #if OW_DEBUG uart_putsP(PSTR("Bus appears to be being held low\n\r")); #endif return OW_BADWIRE; break; } } /* If finding alarming devices issue a different command */ if (alarm_only) OWWriteByte(OW_SEARCH_ALRM_CMD); /* issue the alarming search command */ else OWWriteByte(OW_SEARCH_ROM_CMD); /* issue the search command */ /* pause before beginning the search */ OWdelay(); OWdelay(); OWdelay(); /* loop to do the search */ do { /* read a bit and its compliment */ bit_test = OWReadBit() << 1; bit_test |= OWReadBit(); #if OW_DEBUG sprintf_P(errstr, PSTR("bit_test = %d\n\r"), bit_test); uart_puts(errstr); #endif /* check for no devices on 1-wire */ if (bit_test == 3) { #if OW_DEBUG sprintf_P(errstr, PSTR("bit_test = %d\n\r"), bit_test); uart_puts(errstr); #endif return(OW_BADWIRE); } else { /* all devices coupled have 0 or 1 */ if (bit_test > 0) search_direction = !(bit_test & 0x01); /* bit write value for search */ else { /* if this discrepancy is before the Last Discrepancy * on a previous OWNext then pick the same as last time */ if (bit_number < OW_LastDiscrepancy) search_direction = ((ROM[rom_byte_number] & rom_byte_mask) > 0); else /* if equal to last pick 1, if not then pick 0 */ search_direction = (bit_number == OW_LastDiscrepancy); /* if 0 was picked then record its position in LastZero */ if (search_direction == 0) { last_zero = bit_number; /* check for Last discrepancy in family */ if (last_zero < 9) OW_LastFamilyDiscrepancy = last_zero; } } /* set or clear the bit in the ROM byte rom_byte_number * with mask rom_byte_mask */ if (search_direction == 1) ROM[rom_byte_number] |= rom_byte_mask; else ROM[rom_byte_number] &= ~rom_byte_mask; /* serial number search direction write bit */ OWWriteBit(search_direction); /* increment the byte counter bit_number * and shift the mask rom_byte_mask */ bit_number++; rom_byte_mask <<= 1; /* if the mask is 0 then go to new ROM byte rom_byte_number * and reset mask */ if (rom_byte_mask == 0) { OWCRC(ROM[rom_byte_number], &crcaccum); /* accumulate the CRC */ lastcrc8 = crcaccum; rom_byte_number++; rom_byte_mask = 1; } } } while (rom_byte_number < 8); /* loop until through all ROM bytes 0-7 */ /* if the search was successful then */ if (!(bit_number < 65) || lastcrc8) { if (lastcrc8) { #if OW_DEBUG sprintf_P(errstr, PSTR("Bad CRC (%d)\n\r"), lastcrc8); uart_puts(errstr); #endif next_result = OW_BADCRC; } else { /* search successful so set LastDiscrepancy,LastDevice,next_result */ OW_LastDiscrepancy = last_zero; OW_LastDevice = (OW_LastDiscrepancy == 0); #if OW_DEBUG sprintf_P(errstr, PSTR("Last device = %d\n\r"), OW_LastDevice); uart_puts(errstr); #endif next_result = OW_FOUND; } } } /* if no device found then reset counters so next 'next' will be * like a first */ if (next_result != OW_FOUND || ROM[0] == 0) { OW_LastDiscrepancy = 0; OW_LastDevice = 0; OW_LastFamilyDiscrepancy = 0; } if (next_result == OW_FOUND && ROM[0] == 0x00) next_result = OW_BADWIRE; return next_result; } uint8_t PROGMEM dscrc_table[] = { 0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65, 157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220, 35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98, 190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255, 70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7, 219, 133,103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154, 101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36, 248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185, 140,210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113,147, 205, 17, 79, 173, 243, 112, 46, 204, 146, 211,141, 111, 49, 178, 236, 14, 80, 175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82,176, 238, 50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115, 202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139, 87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22, 233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168, 116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53 }; void OWCRC(uint8_t x, uint8_t *crc) { *crc = pgm_read_byte(&dscrc_table[(*crc) ^ x]); }