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- /*
- Adaptation of Paul Stoffregen's One wire library to the NodeMcu
- The latest version of this library may be found at:
- http://www.pjrc.com/teensy/td_libs_OneWire.html
- Permission is hereby granted, free of charge, to any person obtaining
- a copy of this software and associated documentation files (the
- "Software"), to deal in the Software without restriction, including
- without limitation the rights to use, copy, modify, merge, publish,
- distribute, sublicense, and/or sell copies of the Software, and to
- permit persons to whom the Software is furnished to do so, subject to
- the following conditions:
- The above copyright notice and this permission notice shall be
- included in all copies or substantial portions of the Software.
- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
- MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
- NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
- LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
- OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
- WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
- Much of the code was inspired by Derek Yerger's code, though I don't
- think much of that remains. In any event that was..
- (copyleft) 2006 by Derek Yerger - Free to distribute freely.
- The CRC code was excerpted and inspired by the Dallas Semiconductor
- sample code bearing this copyright.
- //---------------------------------------------------------------------------
- // Copyright (C) 2000 Dallas Semiconductor Corporation, All Rights Reserved.
- //
- // Permission is hereby granted, free of charge, to any person obtaining a
- // copy of this software and associated documentation files (the "Software"),
- // to deal in the Software without restriction, including without limitation
- // the rights to use, copy, modify, merge, publish, distribute, sublicense,
- // and/or sell copies of the Software, and to permit persons to whom the
- // Software is furnished to do so, subject to the following conditions:
- //
- // The above copyright notice and this permission notice shall be included
- // in all copies or substantial portions of the Software.
- //
- // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
- // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
- // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
- // IN NO EVENT SHALL DALLAS SEMICONDUCTOR BE LIABLE FOR ANY CLAIM, DAMAGES
- // OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
- // ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
- // OTHER DEALINGS IN THE SOFTWARE.
- //
- // Except as contained in this notice, the name of Dallas Semiconductor
- // shall not be used except as stated in the Dallas Semiconductor
- // Branding Policy.
- //--------------------------------------------------------------------------
- */
- #include "driver/onewire.h"
- #include "platform.h"
- #include "osapi.h"
- #define noInterrupts ets_intr_lock
- #define interrupts ets_intr_unlock
- #define delayMicroseconds os_delay_us
- // 1 for keeping the parasitic power on H
- #define owDefaultPower 1
- #if ONEWIRE_SEARCH
- // global search state
- static unsigned char ROM_NO[NUM_OW][8];
- static uint8_t LastDiscrepancy[NUM_OW];
- static uint8_t LastFamilyDiscrepancy[NUM_OW];
- static uint8_t LastDeviceFlag[NUM_OW];
- #endif
- void onewire_init(uint8_t pin)
- {
- // pinMode(pin, INPUT);
- platform_gpio_mode(pin, PLATFORM_GPIO_INPUT, PLATFORM_GPIO_PULLUP);
- #if ONEWIRE_SEARCH
- onewire_reset_search(pin);
- #endif
- }
- // Perform the onewire reset function. We will wait up to 250uS for
- // the bus to come high, if it doesn't then it is broken or shorted
- // and we return a 0;
- //
- // Returns 1 if a device asserted a presence pulse, 0 otherwise.
- //
- uint8_t onewire_reset(uint8_t pin)
- {
- uint8_t r;
- uint8_t retries = 125;
- noInterrupts();
- DIRECT_MODE_INPUT(pin);
- interrupts();
- // wait until the wire is high... just in case
- do {
- if (--retries == 0) return 0;
- delayMicroseconds(2);
- } while ( !DIRECT_READ(pin));
- noInterrupts();
- DIRECT_WRITE_LOW(pin);
- interrupts();
- delayMicroseconds(480);
- noInterrupts();
- DIRECT_MODE_INPUT(pin); // allow it to float
- delayMicroseconds(70);
- r = !DIRECT_READ(pin);
- interrupts();
- delayMicroseconds(410);
- return r;
- }
- //
- // Write a bit. Port and bit is used to cut lookup time and provide
- // more certain timing.
- //
- static void onewire_write_bit(uint8_t pin, uint8_t v, uint8_t power)
- {
- if (v & 1) {
- noInterrupts();
- DIRECT_WRITE_LOW(pin);
- delayMicroseconds(5);
- if (power) {
- DIRECT_WRITE_HIGH(pin);
- } else {
- DIRECT_MODE_INPUT(pin); // drive output high by the pull-up
- }
- delayMicroseconds(8);
- interrupts();
- delayMicroseconds(52);
- } else {
- noInterrupts();
- DIRECT_WRITE_LOW(pin);
- delayMicroseconds(65);
- if (power) {
- DIRECT_WRITE_HIGH(pin);
- } else {
- DIRECT_MODE_INPUT(pin); // drive output high by the pull-up
- }
- interrupts();
- delayMicroseconds(5);
- }
- }
- //
- // Read a bit. Port and bit is used to cut lookup time and provide
- // more certain timing.
- //
- static uint8_t onewire_read_bit(uint8_t pin)
- {
- uint8_t r;
- noInterrupts();
- DIRECT_WRITE_LOW(pin);
- delayMicroseconds(5);
- DIRECT_MODE_INPUT(pin); // let pin float, pull up will raise
- delayMicroseconds(8);
- r = DIRECT_READ(pin);
- interrupts();
- delayMicroseconds(52);
- return r;
- }
- //
- // Write a byte. The writing code uses the external pull-up to raise the
- // pin high, if you need power after the write (e.g. DS18S20 in
- // parasite power mode) then set 'power' to 1 and the output driver will
- // be activated at the end of the write. Otherwise the pin will
- // go tri-state at the end of the write to avoid heating in a short or
- // other mishap.
- //
- void onewire_write(uint8_t pin, uint8_t v, uint8_t power /* = 0 */) {
- uint8_t bitMask;
- for (bitMask = 0x01; bitMask; bitMask <<= 1) {
- // send last bit with requested power mode
- onewire_write_bit(pin, (bitMask & v)?1:0, bitMask & 0x80 ? power : 0);
- }
- }
- void onewire_write_bytes(uint8_t pin, const uint8_t *buf, uint16_t count, bool power /* = 0 */) {
- uint16_t i;
- for (i = 0 ; i < count ; i++)
- onewire_write(pin, buf[i], i < count-1 ? owDefaultPower : power);
- }
- //
- // Read a byte
- //
- uint8_t onewire_read(uint8_t pin) {
- uint8_t bitMask;
- uint8_t r = 0;
- for (bitMask = 0x01; bitMask; bitMask <<= 1) {
- if (onewire_read_bit(pin)) r |= bitMask;
- }
- return r;
- }
- void onewire_read_bytes(uint8_t pin, uint8_t *buf, uint16_t count) {
- uint16_t i;
- for (i = 0 ; i < count ; i++)
- buf[i] = onewire_read(pin);
- }
- //
- // Do a ROM select
- //
- void onewire_select(uint8_t pin, const uint8_t rom[8])
- {
- uint8_t i;
- onewire_write(pin, 0x55, owDefaultPower); // Choose ROM
- for (i = 0; i < 8; i++) onewire_write(pin, rom[i], owDefaultPower);
- }
- //
- // Do a ROM skip
- //
- void onewire_skip(uint8_t pin)
- {
- onewire_write(pin, 0xCC, owDefaultPower); // Skip ROM
- }
- void onewire_depower(uint8_t pin)
- {
- noInterrupts();
- DIRECT_MODE_INPUT(pin);
- interrupts();
- }
- #if ONEWIRE_SEARCH
- //
- // You need to use this function to start a search again from the beginning.
- // You do not need to do it for the first search, though you could.
- //
- void onewire_reset_search(uint8_t pin)
- {
- // reset the search state
- LastDiscrepancy[pin] = 0;
- LastDeviceFlag[pin] = FALSE;
- LastFamilyDiscrepancy[pin] = 0;
- int i;
- for(i = 7; ; i--) {
- ROM_NO[pin][i] = 0;
- if ( i == 0) break;
- }
- }
- // Setup the search to find the device type 'family_code' on the next call
- // to search(*newAddr) if it is present.
- //
- void onewire_target_search(uint8_t pin, uint8_t family_code)
- {
- // set the search state to find SearchFamily type devices
- ROM_NO[pin][0] = family_code;
- uint8_t i;
- for (i = 1; i < 8; i++)
- ROM_NO[pin][i] = 0;
- LastDiscrepancy[pin] = 64;
- LastFamilyDiscrepancy[pin] = 0;
- LastDeviceFlag[pin] = FALSE;
- }
- //
- // Perform a search. If this function returns a '1' then it has
- // enumerated the next device and you may retrieve the ROM from the
- // OneWire::address variable. If there are no devices, no further
- // devices, or something horrible happens in the middle of the
- // enumeration then a 0 is returned. If a new device is found then
- // its address is copied to newAddr. Use OneWire::reset_search() to
- // start over.
- //
- // --- Replaced by the one from the Dallas Semiconductor web site ---
- //--------------------------------------------------------------------------
- // Perform the 1-Wire Search Algorithm on the 1-Wire bus using the existing
- // search state.
- // Return TRUE : device found, ROM number in ROM_NO buffer
- // FALSE : device not found, end of search
- //
- uint8_t onewire_search(uint8_t pin, uint8_t *newAddr)
- {
- uint8_t id_bit_number;
- uint8_t last_zero, rom_byte_number, search_result;
- uint8_t id_bit, cmp_id_bit;
- unsigned char rom_byte_mask, search_direction;
- // initialize for search
- id_bit_number = 1;
- last_zero = 0;
- rom_byte_number = 0;
- rom_byte_mask = 1;
- search_result = 0;
- // if the last call was not the last one
- if (!LastDeviceFlag[pin])
- {
- // 1-Wire reset
- if (!onewire_reset(pin))
- {
- // reset the search
- LastDiscrepancy[pin] = 0;
- LastDeviceFlag[pin] = FALSE;
- LastFamilyDiscrepancy[pin] = 0;
- return FALSE;
- }
- // issue the search command
- onewire_write(pin, 0xF0, owDefaultPower);
- // loop to do the search
- do
- {
- // read a bit and its complement
- id_bit = onewire_read_bit(pin);
- cmp_id_bit = onewire_read_bit(pin);
- // check for no devices on 1-wire
- if ((id_bit == 1) && (cmp_id_bit == 1))
- break;
- else
- {
- // all devices coupled have 0 or 1
- if (id_bit != cmp_id_bit)
- search_direction = id_bit; // bit write value for search
- else
- {
- // if this discrepancy if before the Last Discrepancy
- // on a previous next then pick the same as last time
- if (id_bit_number < LastDiscrepancy[pin])
- search_direction = ((ROM_NO[pin][rom_byte_number] & rom_byte_mask) > 0);
- else
- // if equal to last pick 1, if not then pick 0
- search_direction = (id_bit_number == LastDiscrepancy[pin]);
- // if 0 was picked then record its position in LastZero
- if (search_direction == 0)
- {
- last_zero = id_bit_number;
- // check for Last discrepancy in family
- if (last_zero < 9)
- LastFamilyDiscrepancy[pin] = last_zero;
- }
- }
- // set or clear the bit in the ROM byte rom_byte_number
- // with mask rom_byte_mask
- if (search_direction == 1)
- ROM_NO[pin][rom_byte_number] |= rom_byte_mask;
- else
- ROM_NO[pin][rom_byte_number] &= ~rom_byte_mask;
- // serial number search direction write bit
- onewire_write_bit(pin, search_direction, 0);
- // increment the byte counter id_bit_number
- // and shift the mask rom_byte_mask
- id_bit_number++;
- rom_byte_mask <<= 1;
- // if the mask is 0 then go to new SerialNum byte rom_byte_number and reset mask
- if (rom_byte_mask == 0)
- {
- 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 (!(id_bit_number < 65))
- {
- // search successful so set LastDiscrepancy,LastDeviceFlag,search_result
- LastDiscrepancy[pin] = last_zero;
- // check for last device
- if (LastDiscrepancy[pin] == 0)
- LastDeviceFlag[pin] = TRUE;
- search_result = TRUE;
- }
- }
- // if no device found then reset counters so next 'search' will be like a first
- if (!search_result || !ROM_NO[pin][0])
- {
- LastDiscrepancy[pin] = 0;
- LastDeviceFlag[pin] = FALSE;
- LastFamilyDiscrepancy[pin] = 0;
- search_result = FALSE;
- }
- else
- {
- for (rom_byte_number = 0; rom_byte_number < 8; rom_byte_number++)
- {
- newAddr[rom_byte_number] = ROM_NO[pin][rom_byte_number];
- }
- }
- return search_result;
- }
- #endif
- #if ONEWIRE_CRC
- // The 1-Wire CRC scheme is described in Maxim Application Note 27:
- // "Understanding and Using Cyclic Redundancy Checks with Maxim iButton Products"
- //
- #if ONEWIRE_CRC8_TABLE
- // This table comes from Dallas sample code where it is freely reusable,
- // though Copyright (C) 2000 Dallas Semiconductor Corporation
- static const uint8_t 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};
- #ifndef pgm_read_byte
- #define pgm_read_byte(addr) (*(const uint8_t *)(addr))
- #endif
- //
- // Compute a Dallas Semiconductor 8 bit CRC. These show up in the ROM
- // and the registers. (note: this might better be done without to
- // table, it would probably be smaller and certainly fast enough
- // compared to all those delayMicrosecond() calls. But I got
- // confused, so I use this table from the examples.)
- //
- uint8_t onewire_crc8(const uint8_t *addr, uint8_t len)
- {
- uint8_t crc = 0;
- while (len--) {
- crc = pgm_read_byte(dscrc_table + (crc ^ *addr++));
- }
- return crc;
- }
- #else
- //
- // Compute a Dallas Semiconductor 8 bit CRC directly.
- // this is much slower, but much smaller, than the lookup table.
- //
- uint8_t onewire_crc8(const uint8_t *addr, uint8_t len)
- {
- uint8_t crc = 0;
- while (len--) {
- uint8_t inbyte = *addr++;
- uint8_t i;
- for (i = 8; i; i--) {
- uint8_t mix = (crc ^ inbyte) & 0x01;
- crc >>= 1;
- if (mix) crc ^= 0x8C;
- inbyte >>= 1;
- }
- }
- return crc;
- }
- #endif
- #if ONEWIRE_CRC16
- // Compute the 1-Wire CRC16 and compare it against the received CRC.
- // Example usage (reading a DS2408):
- // // Put everything in a buffer so we can compute the CRC easily.
- // uint8_t buf[13];
- // buf[0] = 0xF0; // Read PIO Registers
- // buf[1] = 0x88; // LSB address
- // buf[2] = 0x00; // MSB address
- // WriteBytes(net, buf, 3); // Write 3 cmd bytes
- // ReadBytes(net, buf+3, 10); // Read 6 data bytes, 2 0xFF, 2 CRC16
- // if (!CheckCRC16(buf, 11, &buf[11])) {
- // // Handle error.
- // }
- //
- // @param input - Array of bytes to checksum.
- // @param len - How many bytes to use.
- // @param inverted_crc - The two CRC16 bytes in the received data.
- // This should just point into the received data,
- // *not* at a 16-bit integer.
- // @param crc - The crc starting value (optional)
- // @return True, iff the CRC matches.
- bool onewire_check_crc16(const uint8_t* input, uint16_t len, const uint8_t* inverted_crc, uint16_t crc)
- {
- crc = ~onewire_crc16(input, len, crc);
- return (crc & 0xFF) == inverted_crc[0] && (crc >> 8) == inverted_crc[1];
- }
- // Compute a Dallas Semiconductor 16 bit CRC. This is required to check
- // the integrity of data received from many 1-Wire devices. Note that the
- // CRC computed here is *not* what you'll get from the 1-Wire network,
- // for two reasons:
- // 1) The CRC is transmitted bitwise inverted.
- // 2) Depending on the endian-ness of your processor, the binary
- // representation of the two-byte return value may have a different
- // byte order than the two bytes you get from 1-Wire.
- // @param input - Array of bytes to checksum.
- // @param len - How many bytes to use.
- // @param crc - The crc starting value (optional)
- // @return The CRC16, as defined by Dallas Semiconductor.
- uint16_t onewire_crc16(const uint8_t* input, uint16_t len, uint16_t crc)
- {
- static const uint8_t oddparity[16] =
- { 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0 };
- uint16_t i;
- for (i = 0 ; i < len ; i++) {
- // Even though we're just copying a byte from the input,
- // we'll be doing 16-bit computation with it.
- uint16_t cdata = input[i];
- cdata = (cdata ^ crc) & 0xff;
- crc >>= 8;
- if (oddparity[cdata & 0x0F] ^ oddparity[cdata >> 4])
- crc ^= 0xC001;
- cdata <<= 6;
- crc ^= cdata;
- cdata <<= 1;
- crc ^= cdata;
- }
- return crc;
- }
- #endif
- #endif
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