--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/1wire.c	Sun Jul 11 00:45:50 2004 +0930
@@ -0,0 +1,530 @@
+/*
+ * Various 1 wire routines
+ * Search routine is copied from the Dallas owpd library with mods.
+ *
+ * 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 "1wire.h"
+
+void		uart_putsP(const char *addr);
+void		uart_puts(const char *addr);
+void		uart_getc();
+int		uart_putc(char c);
+
+static uint8_t OW_LastDevice = 0;
+static uint8_t OW_LastDiscrepancy = 0;
+static uint8_t OW_LastFamilyDiscrepancy = 0;
+
+static void
+OWdelay(void) {
+      asm volatile (
+	  "ldi r21, 50\n\t"
+	  "_OWdelay:\n\t"
+	  "nop\n\t"
+	  "nop\n\t"
+	  "nop\n\t"
+	  "nop\n\t"
+	  "nop\n\t"
+	  "nop\n\t"
+	  "nop\n\t"
+	  "nop\n\t"
+	  "nop\n\t"
+	  "nop\n\t"
+	  "nop\n\t"
+	  "nop\n\t"
+	  "nop\n\t"
+	  "dec r21\n\t"
+	  "brne _OWdelay\n\t"
+	  ::: "r21");
+}
+
+/*-----------------------------------------------------------------------------
+ * Generate a 1-Wire reset, return 1 if no presence detect was found,
+ * return 0 otherwise.
+ * (NOTE: Does not handle alarm presence from DS2404/DS1994)
+ */
+int
+OWTouchReset(void) {
+    uint8_t	result;
+
+    asm volatile (
+	/* Delay G (0 usec) */
+	"\n\t"
+	/* Drive bus low */
+	"cbi %[out], %[opin]\n\t"
+	"sbi %[ddr], %[opin]\n\t"
+	/* Delay H (480 usec) */
+	"ldi r21, 120\n\t"
+	"loopH:\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"dec r21\n\t"
+	"brne loopH\n\t"
+	/* Release bus */
+	"cbi %[ddr], %[opin]\n\t"
+	/* Delay I (70 usec) */
+	"ldi r21, 35\n\t"
+	"loopI:\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"dec r21\n\t"
+	"brne loopI\n\t"
+	/* Sample for presense */
+	"ldi %[result], 0\n\t"
+	"sbi %[ddr], 1\n\t"
+	"sbi %[out], 1\n\t"
+	/* 1 == no presence */
+	"sbic %[in], %[ipin]\n\t"
+	"ldi %[result], 1\n\t"
+	"cbi %[out], 1\n\t"
+
+	: [result] "=r" (result)			/* Outputs */
+	: [out]  "I" (_SFR_IO_ADDR(OWIREOUTPORT)),	/* Inputs */
+	  [ddr]  "I" (_SFR_IO_ADDR(OWIREDDR)),
+	  [opin] "I" (OWIREOUTPIN),
+	  [in]   "I" (_SFR_IO_ADDR(OWIREINPORT)),
+	  [ipin] "I" (OWIREINPIN)
+	: "r21");				/* Clobbers */
+
+    return(result);
+}
+
+/*-----------------------------------------------------------------------------
+ * Send a 1-wire write bit.
+ */
+void
+OWWriteBit(int bit) {
+    OWdelay();
+    if (bit) {
+	asm volatile (
+	    /* Drive bus low */
+	    "cbi %[out], %[pin]\n\t"
+	    "sbi %[ddr], %[pin]\n\t"
+	    /* Delay A (6 usec) */
+	    "ldi r21, 1\n\t"
+	    "loopA:\n\t"
+	    "nop\n\t"
+	    "dec r21\n\t"
+	    "brne loopA\n\t"
+	    /* Release bus */
+	    "cbi %[ddr], %[pin]\n\t"
+	    /* Delay B (64 usec) */
+	    "ldi r21, 32\n\t"
+	    "loopB:\n\t"
+	    "nop\n\t"
+	    "nop\n\t"
+	    "nop\n\t"
+	    "nop\n\t"
+	    "nop\n\t"
+	    "dec r21\n\t"
+	    "brne loopB\n\t"
+	    :						/* Outputs */
+	    : [out] "I" (_SFR_IO_ADDR(OWIREOUTPORT)),	/* Inputs */
+	      [ddr] "I" (_SFR_IO_ADDR(OWIREDDR)),
+	      [pin] "I" (OWIREOUTPIN)
+	    : "r21");					/* Clobbers */
+    } else {
+	asm volatile (
+	    /* Drive bus low */
+	    "cbi %[out], %[pin]\n\t"
+	    "sbi %[ddr], %[pin]\n\t"
+	    /* Delay C (60 usec) */
+	    "ldi r21, 30\n\t"
+	    "loopC:\n\t"
+	    "nop\n\t"
+	    "nop\n\t"
+	    "nop\n\t"
+	    "nop\n\t"
+	    "nop\n\t"
+	    "dec r21\n\t"
+	    "brne loopC\n\t"
+	    /* Release bus */
+	    "cbi %[ddr], %[pin]\n\t"
+	    /* Delay D (10 usec) */
+	    "ldi r21, 9\n\t"
+	    "loopD:\n\t"
+	    "nop\n\t"
+	    "dec r21\n\t"
+	    "brne loopD\n\t"
+	    :						/* Outputs */
+	    : [out] "I" (_SFR_IO_ADDR(OWIREOUTPORT)),	/* Inputs */
+	      [ddr] "I" (_SFR_IO_ADDR(OWIREDDR)),
+	      [pin] "I" (OWIREOUTPIN)
+	    : "r21");					/* Clobbers */
+    }
+}
+
+/*-----------------------------------------------------------------------------
+ * Read a bit from the 1-wire bus and return it.
+ */
+int
+OWReadBit(void) {
+    uint8_t	result;
+
+    OWdelay();
+    
+    asm volatile (
+	/* Drive bus low */
+	"cbi %[out], %[opin]\n\t"
+	"sbi %[ddr], %[opin]\n\t"
+	/* Delay A (6 usec) */
+	"ldi r21, 1\n\t"
+	"loopA1:\n\t"
+	"dec r21\n\t"
+	"brne loopA1\n\t"
+	/* Release bus */
+	"cbi %[ddr], %[opin]\n\t"
+	/* Delay E (9 usec) */
+	"ldi r21, 8\n\t"
+	"loopE:\n\t"
+	"nop\n\t"
+	"dec r21\n\t"
+	"brne loopE\n\t"
+	/* Sample */
+	"ldi %[res], 0\n\t"
+	"sbic %[in], %[ipin]\n\t"
+	"ldi %[res], 1\n\t"
+
+	/* Delay F (55 usec) */
+	"ldi r21, 27\n\t"
+	"loopF:\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"nop\n\t"
+	"dec r21\n\t"
+	"brne loopF\n\t"
+
+	: [res]  "=r" (result) 				/* Outputs */
+	: [out]  "I" (_SFR_IO_ADDR(OWIREOUTPORT)),	/* Inputs */
+	  [ddr]  "I" (_SFR_IO_ADDR(OWIREDDR)),
+	  [opin] "I" (OWIREOUTPIN),
+	  [in]   "I" (_SFR_IO_ADDR(OWIREINPORT)),
+	  [ipin] "I" (OWIREINPIN)	
+	: "r21");					/* Clobbers */
+
+    return(result);
+}
+
+/*-----------------------------------------------------------------------------
+ * Write a byte to the 1-wire bus
+ */
+void
+OWWriteByte(uint8_t data) {
+    int i;
+    
+    /* Send LSB first */
+    for (i = 0; i < 8; i++) {
+	OWWriteBit(data & 0x01);
+	data >>= 1;
+    }
+}
+
+/*-----------------------------------------------------------------------------
+ * Read a byte from the 1-wire bus
+ */
+int
+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.
+ */
+int
+OWTouchByte(uint8_t data) {
+    int 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) {
+    int		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)
+ *
+ * Returns 1 when something is found, 0 if nothing present
+ */
+int
+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 */
+int
+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, next_result;
+    uint8_t	rom_byte_mask;
+    uint8_t	lastcrc8, crcaccum;
+    char	errstr[30];
+
+    /* Init for search */
+   bit_number = 1;
+   last_zero = 0;
+   rom_byte_number = 0;
+   rom_byte_mask = 1;
+   next_result = 0;
+   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
+         if (OWTouchReset()) {
+	     /* reset the search */
+	     OW_LastDiscrepancy = 0;
+	     OW_LastFamilyDiscrepancy = 0;
+#if OW_DEBUG
+	     uart_putsP(PSTR("No devices on bus\n\r"));
+#endif
+	     return 0;
+         }
+       }
+
+       /* 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) {
+	      sprintf_P(errstr, PSTR("bit_test = %d\n\r"), bit_test);
+	      uart_puts(errstr);
+	      break;
+	  }
+	  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) {
+	      sprintf_P(errstr, PSTR("Bad CRC (%d)\n\r"), lastcrc8);
+	      uart_puts(errstr);
+	      next_result = 0;
+	  } 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 = 1;
+	  }
+      }
+   }
+
+   /* if no device found then reset counters so next 'next' will be
+    * like a first */
+   if (!next_result || !ROM[0]) {
+       OW_LastDiscrepancy = 0;
+       OW_LastDevice = 0;
+       OW_LastFamilyDiscrepancy = 0;
+       next_result = 0;
+   }
+
+   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]);
+}