OneWire Library lets you access 1-wire devices made by Maxim/Dallas, such as temperature sensors
Dependents: OneWireTest mbed_blinky Affich_Lum_Moist Projetv0 ... more
#include "mbed.h" #include "OneWire.h" OneWire owBus(p21); int main() { char _id[16]; DeviceAddresses* devAddresses = owBus.getFoundDevAddresses(); uint8_t foundNum = owBus.getFoundDevNum(); printf("OneWire: found %d devices\r\n", foundNum); while(1) { OneWireDeviceTemperature::startConversationForAll(&owBus, OWTEMP_11_BIT); for (uint8_t i = 0; i < foundNum; i++) { OneWireDevice* owDevice = OneWireDeviceFactory::init(&owBus, (*devAddresses)[i]); if (owDevice->getFamily() != ONEWIRE_DS18B20_FAMILY) // currently only DS18B20 supports continue; owDevice->generateId(_id); printf("OneWire: device #%s = %.4f*C\r\n", _id, (float) owDevice->sendGetCommand(GET_TEMPERATURE)); delete owDevice; } wait(5); } }
Diff: OneWire.cpp
- Revision:
- 0:b9cd1d4dcc1f
- Child:
- 1:74dcd0c7d5d4
diff -r 000000000000 -r b9cd1d4dcc1f OneWire.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/OneWire.cpp Mon Nov 12 19:44:46 2012 +0000 @@ -0,0 +1,309 @@ +/* Copyright (c) 2012, Ivan Kravets <me@ikravets.com>, www.ikravets.com. MIT License + * + * 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. + */ + +#include "OneWire.h" +#include "ds18b20.h" + +uint8_t const OneWire::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 +}; + +OneWire::OneWire(PinName pin) : DIO(pin) +{ + DIO.output(); + DIO = 0; + DIO.input(); + + reset(); + findDevAddresses(); +} + + +uint8_t OneWire::reset(void) +{ + uint8_t presence; + DIO.output(); + DIO = 0; + wait_us(480); + DIO.input(); + wait_us(70); + presence = DIO; + wait_us(410); + return(presence); +} + +uint8_t OneWire::readBit(void) +{ + uint8_t retval; + wait_us(1); + DIO.output(); + DIO = 0; + wait_us(2); + DIO.input(); + wait_us(10); + retval=DIO; + wait_us(48); + return(retval); +} + +uint8_t OneWire::readByte(void) +{ + uint8_t i, value=0; + for (i=0; i<8; i++) { + if (readBit()) value|=0x01<<i; + } + return(value); +} + + +void OneWire::writeBit(uint8_t bitval) +{ + wait_us(1); + DIO.output(); + DIO = 0; + wait_us(10); + if (bitval==1) DIO = 1; + wait_us(50); + DIO.input(); +} + + +void OneWire::writeByte(uint8_t val) +{ + uint8_t i; + uint8_t temp; + for (i=0; i<8; i++) { + temp = val>>i; + temp &= 0x01; + writeBit(temp); + } +} + +uint8_t OneWire::calcCRC( uint8_t x) +{ + return dscrc_table[dowcrc^x]; +} + +void OneWire::skip() +{ + writeByte(0xcc); +} + + +void OneWire::select(uint8_t* devAddr) +{ + writeByte(0x55); + for (uint8_t i=0; i<8; i++) { + writeByte(devAddr[i]); + } +} + +void OneWire::sendGlobalCommand(uint8_t cmd) +{ + reset(); + skip(); + writeByte(cmd); +} + + +void OneWire::resetSearch(void) +{ + lastDiscrep = 0; + doneFlag = FALSE; +} + +uint8_t OneWire::search(uint8_t* devAddr) +{ + uint8_t m = 1; // ROM Bit index + uint8_t n = 0; // ROM Byte index + uint8_t k = 1; // bit mask + uint8_t x = 0; + uint8_t discrepMarker = 0; // discrepancy marker + uint8_t g; // Output bit + uint8_t nxt; // return value + uint8_t flag; + nxt = FALSE; // set the next flag to false + dowcrc = 0; // reset the dowcrc + DeviceAddress ROM; + + flag = reset(); // reset the 1-Wire + if (flag||doneFlag) { // no parts -> return false + lastDiscrep = 0; // reset the search + return FALSE; + } + + writeByte(0xF0); // send SearchROM command + do { // for all eight bytes + x = 0; + if (readBit()==1) x = 2; + wait_us(120); + if (readBit()==1) x |= 1; // and its complement + if (x ==3) // there are no devices on the 1-Wire + break; + else { + if (x>0) // all devices coupled have 0 or 1 + g = x>>1; // bit write value for search + else { + // if this discrepancy is before the last discrepancy on a previous Next then pick the same as last time + if (m<lastDiscrep) + g = ((ROM[n]&k)>0); + else // if equal to last pick 1 + g = (m==lastDiscrep); // if not then pick 0 + // if 0 was picked then record position with mask k + if (g==0) discrepMarker = m; + } + if (g==1) // isolate bit in ROM[n] with mask k + ROM[n] |= k; + else + ROM[n] &= ~k; + writeBit(g); // ROM search write + m++; // increment bit counter m + k = k<<1; // and shift the bit mask k + if (k==0) { // if the mask is 0 then go to new ROM // byte n and reset mask + dowcrc = calcCRC(ROM[n]); // accumulate the CRC + n++; + k++; + } + } + } while (n<8); //loop until through all ROM bytes 0-7 + if (m<65||dowcrc) // if search was unsuccessful then + lastDiscrep=0; // reset the last discrepancy to 0 + else { // search was successful, so set lastDiscrep, lastOne, nxt + lastDiscrep = discrepMarker; + doneFlag = (lastDiscrep==0); + nxt = TRUE; // indicates search is not complete yet, more parts remain + } + + for (uint8_t i = 0; i < 8; i++) + devAddr[i] = ROM[i]; + + return nxt; +} + +void OneWire::findDevAddresses(void) +{ + foundDevNum = 0; + resetSearch(); + + DeviceAddress devAddr; + while (search(devAddr)) { + foundDevNum++; + } + delete devAddr; + + wait_us(250); + resetSearch(); + + foundDevAdresses = (DeviceAddresses*) malloc(foundDevNum * sizeof(int)); + for (uint8_t i = 0; i < foundDevNum; i++) { + foundDevAdresses[i] = (DeviceAddress*) malloc(sizeof(DeviceAddress)); + search((*foundDevAdresses)[i]); + } + + printf("OneWire Bus: Found %d devices\r\n", getFoundDevNum() ); +} + +DeviceAddresses* OneWire::getFoundDevAddresses() +{ + return foundDevAdresses; +} + +uint8_t OneWire::getFoundDevNum() +{ + return foundDevNum; +} + + + +// ======================== OneWireDevice Class ============================= +OneWireDevice* OneWireDeviceFactory::init(OneWire* ow, DeviceAddress address) +{ + switch (address[0]) { + case ONEWIRE_DS18B20_FAMILY: + return new OneWireDeviceDS18B20(ow, address); + } + + return NULL; +} + +OneWireDevice::OneWireDevice(OneWire* ow, DeviceAddress devAddr) +{ + owBus = ow; + for (uint8_t i = 0; i < 8; i++) + address[i] = devAddr[i]; + + +} + +void OneWireDevice::generateId(char* id) +{ + sprintf(id, "%02X%02X%02X%02X%02X%02X%02X%02X", address[0], address[1],address[2],address[3],address[4],address[5],address[6],address[7]); +} + +uint8_t OneWireDevice::getFamily() +{ + return address[0]; +} + + +void OneWireDeviceTemperature::startConversationForAll(OneWire* owBus, uint8_t resolution) +{ + DeviceAddresses* devAddresses = owBus->getFoundDevAddresses(); + for (uint8_t i = 0; i < owBus->getFoundDevNum(); i++) { + OneWireDevice* owDevice = OneWireDeviceFactory::init(owBus, (*devAddresses)[i]); + if (owDevice->getFamily() != ONEWIRE_DS18B20_FAMILY) + continue; + + owDevice->sendSetCommand(SET_TEMPERATURE_RESOLUTION, resolution); + delete owDevice; + } + //delete devAddresses; + + owBus->sendGlobalCommand(0x44); + + switch (resolution) { + case OWTEMP_9_BIT: + wait_us(94); + break; + case OWTEMP_10_BIT: + wait_us(188); + break; + case OWTEMP_11_BIT: + wait_us(375); + break; + case OWTEMP_12_BIT: + default: + wait_us(750); + break; + } +}; \ No newline at end of file