teste de publish
Fork of DS1820 by
Diff: DS1820.h
- Revision:
- 0:61d83318f2d6
- Child:
- 1:6a427f54e82c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/DS1820.h Sun Dec 19 05:40:28 2010 +0000 @@ -0,0 +1,252 @@ +/* mbed DS1820 Library, for the Dallas (Maxim) 1-Wire Digital Thermometer + * Copyright (c) 2010, Michael Hagberg Michael@RedBoxCode.com + * + * 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. + */ + +#ifndef MBED_DS1820_H +#define MBED_DS1820_H + +#include "mbed.h" + +// ****** THIS GLOBAL VARIABLES MUST BE DEFINED IN main.cpp + +// Global variables shared between all DS1820 objects +//bool DS1820_done_flag; +//int DS1820_last_descrepancy; +//char DS1820_search_ROM[8]; + +/** DS1820 Dallas 1-Wire Temperature Probe + * + * Example: + * @code + * #include "mbed.h" + * + * #include "TextLCD.h" + * #include "DS1820.h" + * + * TextLCD lcd(p25, p26, p21, p22, p23, p24, TextLCD::LCD16x2); // rs, e, d0-d3, layout + * + * const int MAX_PROBES = 16; + * DS1820* probe[MAX_PROBES]; + * + * int main() { + * int i; + * int devices_found=0; + * // Initialize the probe array to DS1820 objects + * for (i = 0; i < MAX_PROBES; i++) + * probe[i] = new DS1820(p27); + * // Initialize global state variables + * probe[0]->search_ROM_setup(); + * // Loop to find all devices on the data line + * while (probe[devices_found]->search_ROM() and devices_found<MAX_PROBES-1) + * devices_found++; + * // If maximum number of probes are found, + * // bump the counter to include the last array entry + * if (probe[devices_found]->ROM[0] != 0xFF) + * devices_found++; + * + * lcd.cls(); + * if (devices_found==0) + * lcd.printf("No devices found"); + * else { + * while (true) { + * probe[0]->convert_temperature(DS1820::all_devices); + * lcd.cls(); + * for (i=0; i<devices_found; i++) { + * lcd.printf("%3.1f ",probe[i]->temperature('f')); + * } + * } + * } + * } + * @endcode + */ + +class DS1820 { +public: + enum devices{ + this_device, // command applies to only this device + all_devices }; // command applies to all devices + + /** Create a probe object connected to the specified pins + * + * @param data_pin DigitalInOut pin for the data bus + * @param power_pin DigitalOut pin to control the power MOSFET + */ + DS1820(PinName data_pin, PinName power_pin); // Constructor with parasite power pin + + /** Create a probe object connected to the specified pin + * this is used when all probes are externally powered + * + * @param data_pin DigitalInOut pin for the data bus + */ + DS1820(PinName data_pin); + + /** ROM is a copy of the internal DS1820's ROM + * It's created during the search_ROM() or search_alarm() commands + * + * ROM[0] is the Dallas Family Code + * ROM[1] thru ROM[6] is the 48-bit unique serial number + * ROM[7] is the device CRC + */ + char ROM[8]; + + /** RAM is a copy of the internal DS1820's RAM + * It's updated during the read_RAM() command + * which is automaticaly called from any function + * using the RAM values. + */ + char RAM[9]; + + /* This function copies the DS1820's RAM into the object's + * RAM[]. + */ + void read_RAM(); + + /** This routine initializes the global variables used in + * the search_ROM() and search_alarm() funtions. It should + * be called once before looping to find devices. + */ + void search_ROM_setup(); + + /** This routine will search for an unidentified device + * on the bus. It uses the variables in search_ROM_setup + * to remember the pervious ROM address found. + * It will return FALSE if there were no new devices + * discovered on the bus. + */ + bool search_ROM(); + + /** This routine will search for an unidentified device + * which has the temperature alarm bit set. It uses the + * variables in search_ROM_setup to remember the pervious + * ROM address found. It will return FALSE if there were + * no new devices with alarms discovered on the bus. + */ + bool search_alarm(); + + /** This routine will read the ROM (Family code, serial number + * and Checksum) from a dedicated device on the bus. + * + * NOTE: This command can only be used when there is only one + * DS1820 on the bus. If this command is used when there + * is more than one slave present on the bus, a data + * collision will occur when all the DS1820s attempt to + * respond at the same time. + */ + void read_ROM(); + + /** This routine will initiate the temperature conversion within + * a DS1820. There is a built in 750ms delay to allow the + * conversion to complete. + * + * To update all probes on the bus, use a statement such as this: + * probe[0]->convert_temperature(DS1820::all_devices); + * + * @param allows the fnction to apply to a specific device or + * to all devices on the 1-Wire bus. + */ + void convert_temperature(devices device=this_device); + + /** This function will return the probe temperature. This function + * uses the count remainding values to interpolate the temperature + * to about 1/150th of a degree. Whereas the probe is not spec to + * that precision. It does seem to give a smooth reading to the + * tenth of a degree. + * + * @param scale, may be either 'c' or 'f' + * @returns temperature for that scale + */ + float temperature(char scale='c'); + + /** This function calculates the ROM checksum and compares it to the + * CRC value stored in ROM[7]. + * + * @returns true if the checksum matches, otherwise false. + */ + bool ROM_checksum_error(); + + /** This function calculates the RAM checksum and compares it to the + * CRC value stored in RAM[8]. + * + * @returns true if the checksum matches, otherwise false. + */ + bool RAM_checksum_error(); + + /** This funtion returns the values stored in the temperature + * alarm registers. + * + * @returns a 16 bit integer of TH (upper byte) and TL (lower byte). + */ + int read_scratchpad(); + + /** This function will store the passed data into the DS1820's RAM. + * Note: It does NOT save the data to the EEPROM for retention + * during cycling the power off and on. + * + * @param a 16 bit integer of TH (upper byte) and TL (lower byte). + */ + void write_scratchpad(int data); + + /** This function will transfer the TH and TL registers from the + * DS1820's RAM into the EEPROM. + * Note: There is a built in 10ms delay to allow for the + * completion of the EEPROM write cycle. + * + * @param allows the fnction to apply to a specific device or + * to all devices on the 1-Wire bus. + */ + void store_scratchpad(devices device=this_device); + + /** This function will copy the stored values from the EEPROM + * into the DS1820's RAM locations for TH and TL. + * + * @param allows the fnction to apply to a specific device or + * to all devices on the 1-Wire bus. + */ + int recall_scratchpad(devices device=this_device); + + /** This function will return the type of power supply for + * a specific device. It can also be used to query all devices + * looking for any device that is parasite powered. + * + * @returns true if the device (or all devices) are Vcc powered, + * returns false if the device (or ANY device) is parasite powered. + */ + bool read_power_supply(devices device=this_device); + +private: + bool _parasite_power; + char CRC_byte (char CRC, char byte ); + bool onewire_reset(); + void match_ROM(); + void skip_ROM(); + bool search_ROM_routine(char command); + void onewire_bit_out (bool bit_data); + void onewire_byte_out(char data); + bool onewire_bit_in(); + char onewire_byte_in(); + +protected: + DigitalInOut _datapin; + DigitalOut _parasitepin; +}; + + +#endif