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); } }
OneWire.cpp
- Committer:
- ivank
- Date:
- 2012-12-17
- Revision:
- 1:74dcd0c7d5d4
- Parent:
- 0:b9cd1d4dcc1f
- Child:
- 2:07da4deb7135
File content as of revision 1:74dcd0c7d5d4:
/* 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(0xcc); // Skip ROM command. owBus->sendGlobalCommand(0x44); // wait_us(750); 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; } };