Ernesto Palacios
DS1820
Diff: DS1820.h
- Revision:
- 5:2cd4928e8147
- Parent:
- 3:8f2b7f4940b5
- Child:
- 6:abfdd851218a
--- a/DS1820.h Wed Aug 07 11:02:10 2013 +0000
+++ b/DS1820.h Mon Feb 24 21:23:14 2014 +0000
@@ -24,60 +24,31 @@
#define MBED_DS1820_H
#include "mbed.h"
-
-// ****** THIS GLOBAL VARIABLES MUST BE DEFINED IN main.cpp
+#include "LinkedList.h"
-// Global variables shared between all DS1820 objects
-//bool DS1820_done_flag;
-//int DS1820_last_descrepancy;
-//char DS1820_search_ROM[8];
+#define FAMILY_CODE _ROM[0]
+#define FAMILY_CODE_DS1820 0x10
+#define FAMILY_CODE_DS18B20 0x28
+#define FAMILY_CODE_DS1822 0x22
/** 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];
- *
+ * DS1820 probe(DATA_PIN);
+ *
* 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(true, DS1820::all_devices);
- * lcd.cls();
- * for (i=0; i<devices_found; i++) {
- * lcd.printf("%3.1f ",probe[i]->temperature('f'));
- * }
- * }
+ * while(1) {
+ * probe.convertTemperature(true, DS1820::all_devices); //Start temperature conversion, wait until ready
+ * printf("It is %3.1foC\r\n", probe.temperature());
+ * wait(1);
* }
* }
* @endcode
*/
-
class DS1820 {
public:
enum devices{
@@ -85,84 +56,28 @@
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
+ *
+ * The probe might either by regular powered or parasite powered. If it is parasite
+ * powered and power_pin is set, that pin will be used to switch an external mosfet connecting
+ * data to Vdd. If it is parasite powered and the pin is not set, the regular data pin
+ * is used to supply extra power when required. This will be sufficient as long as the
+ * number of probes is limitted.
*
* @param data_pin DigitalInOut pin for the data bus
+ * @param power_pin DigitalOut (optional) pin to control the power MOSFET
+ * @param power_polarity bool (optional) which sets active state (0 for active low (default), 1 for active high)
*/
- DS1820(PinName data_pin);
-
- /** ROM is a copy of the internal DS1820's ROM
- * It is 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];
- #define FAMILY_CODE ROM[0]
- #define FAMILY_CODE_DS1820 0x10
- #define FAMILY_CODE_DS18S20 0x10
- #define FAMILY_CODE_DS18B20 0x28
-
- /** 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 except RAM_checksum_error.
- */
- char RAM[9];
-
- /** This function copies the DS1820's RAM into the object's
- * RAM[]. It is automaticaly called by temperature(),
- * read_scratchpad(), and recall_scratchpad() of a single probe.
- */
- void read_RAM();
+ DS1820(PinName data_pin, PinName power_pin = NC, bool power_polarity = 0); // Constructor with parasite power pin
+ ~DS1820();
- /** 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.
+ /** Function to see if there are DS1820 devices left on a pin which do not have a corresponding DS1820 object
+ *
+ * @return - true if there are one or more unassigned devices, otherwise false
*/
- 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();
+ static bool unassignedProbe(PinName pin);
/** This routine will initiate the temperature conversion within
- * one or all DS1820 probes. There is an optional built in delay
- * (up to 750ms) to allow the conversion to complete.
- *
- * To update all probes on the bus, use a statement such as this:
- * probe[0]->convert_temperature(true, DS1820::all_devices);
+ * one or all DS1820 probes.
*
* @param wait if true or parisitic power is used, waits up to 750 ms for
* conversion otherwise returns immediatly.
@@ -170,33 +85,15 @@
* to all devices on the 1-Wire bus.
* @returns milliseconds untill conversion will complete.
*/
- int convert_temperature(bool wait, devices device=this_device);
+ int convertTemperature(bool wait, devices device=this_device);
/** This function will return the probe temperature. Approximately 10ms per
* probe to read its RAM, do CRC check and convert temperature on the LPC1768.
- * 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, or -1000.0 if CRC error detected.
*/
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 checksums mis-match, otherwise false.
- */
- bool ROM_checksum_error();
-
- /** This function calculates the RAM checksum and compares it to the
- * CRC value stored in RAM[8]. Approx 10 us on LPC1768.
- *
- * @returns true if the checksums mis-matche, otherwise false.
- */
- bool RAM_checksum_error();
/** This function sets the temperature resolution for the DS18B20
* in the configuration register.
@@ -204,65 +101,36 @@
* @param a number between 9 and 12 to specify resolution
* @returns true if successful
*/
- bool set_configuration_bits(unsigned int resolution);
-
- /** This function 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 function 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);
+ bool setResolution(unsigned int resolution);
private:
bool _parasite_power;
- char CRC_byte (char CRC, char byte );
- bool onewire_reset();
+ bool _power_mosfet;
+ bool _power_polarity;
+
+ static char CRC_byte (char CRC, char byte );
+ static bool onewire_reset(DigitalInOut *pin);
void match_ROM();
void skip_ROM();
- bool search_ROM_routine(char command);
- void onewire_bit_out (bool bit_data);
+ static bool search_ROM_routine(DigitalInOut *pin, char command, char *ROM_address);
+ static void onewire_bit_out (DigitalInOut *pin, bool bit_data);
void onewire_byte_out(char data);
- bool onewire_bit_in();
+ static bool onewire_bit_in(DigitalInOut *pin);
char onewire_byte_in();
+ static bool ROM_checksum_error(char *_ROM_address);
+ bool RAM_checksum_error();
+ void read_RAM();
+ static bool unassignedProbe(DigitalInOut *pin, char *ROM_address);
+ void write_scratchpad(int data);
+ bool read_power_supply(devices device=this_device);
-protected:
DigitalInOut _datapin;
DigitalOut _parasitepin;
+
+ char _ROM[8];
+ char RAM[9];
+
+ static LinkedList<node> probes;
};