aitouares jeremy
DS18S20
Revision 0:5b6520e71eb6, committed 2012-04-26
- Comitter:
- aitouares
- Date:
- Thu Apr 26 14:18:31 2012 +0000
- Commit message:
Changed in this revision
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/DS18S20.h Thu Apr 26 14:18:31 2012 +0000
@@ -0,0 +1,535 @@
+ /*** D'apres : *********************************************************
+ *
+ * FILENAME: ds1820.h
+ * DATE: 25.02.2005
+ * AUTHOR: Christian Stadler
+ *
+ * DESCRIPTION: Driver for DS1820 1-Wire Temperature sensor (Dallas)
+ *
+ ******************************************************************************/
+#include "mbed.h"
+DigitalInOut DQ (p15); // broche DQ relie a la broche p15 du MBED
+DigitalOut G__MOS_P (p16);
+Serial pc(USBTX, USBRX); // tx, rx
+/* -------------------------------------------------------------------------- */
+/* DS1820 Timing Parameters */
+/* -------------------------------------------------------------------------- */
+#define DS1820_RST_PULSE 480 /* master reset pulse time in [us] */
+#define DS1820_MSTR_BITSTART 2 /* delay time for bit start by master */
+#define DS1820_PRESENCE_WAIT 40 /* delay after master reset pulse in [us] */
+#define DS1820_PRESENCE_FIN 480 /* dealy after reading of presence pulse [us] */
+#define DS1820_BITREAD_DLY 5 /* bit read delay */
+#define DS1820_BITWRITE_DLY 100 /* bit write delay */
+
+
+/* -------------------------------------------------------------------------- */
+/* DS1820 Registers */
+/* -------------------------------------------------------------------------- */
+
+#define DS1820_REG_TEMPLSB 0
+#define DS1820_REG_TEMPMSB 1
+#define DS1820_REG_CNTREMAIN 6
+#define DS1820_REG_CNTPERSEC 7
+#define DS1820_SCRPADMEM_LEN 9 // length of scratchpad memory
+
+#define DS1820_ADDR_LEN 8
+
+
+/* -------------------------------------------------------------------------- */
+/* DS1820 Commands */
+/* -------------------------------------------------------------------------- */
+
+#define DS1820_CMD_SEARCHROM 0xF0 // recherche des differents DS1820 et de leur numROMs
+#define DS1820_CMD_READROM 0x33 // idem que SEARCHROM mais utilise pour 1 seul DS1820
+#define DS1820_CMD_MATCHROM 0x55 // permet de communiquer avec un DS1820 en particulier grace a son numROM
+#define DS1820_CMD_SKIPROM 0xCC // permet de communiquer avec tous les DS1820 en meme temps
+#define DS1820_CMD_ALARMSEARCH 0xEC // permet de dialoguer seulement avec les DS1820 qui ont un flag
+#define DS1820_CMD_CONVERTTEMP 0x44 // permet de lancer un convertion de la temperature, le resultat sera stocke dans le scratchpad
+#define DS1820_CMD_WRITESCRPAD 0x4E // permet au MBED d'ecrire deux octets dans le scratchpad dont un dans le registre TH et un dans le registre TL
+#define DS1820_CMD_READSCRPAD 0xBE // permet au MBED de lire le scratchpad
+#define DS1820_CMD_COPYSCRPAD 0x48 // permet de copier le scratchpad et les registres TH, TL stocke dans EEPROM
+#define DS1820_CMD_RECALLEE 0xB8 // rappel les valeur de declenchement de l'alarme
+
+
+#define DS1820_FAMILY_CODE_DS18B20 0x28
+#define DS1820_FAMILY_CODE_DS18S20 0x10
+
+char dowcrc=0; // crc is accumulated in this variable
+// crc lookup table
+char const 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
+};
+
+/* -------------------------------------------------------------------------- */
+bool doneFlag; // declaration d'une variable booleenne "doneFlag"
+char lastDiscrep,numROMs; // declaration des variables lastDiscrep et numROMs
+char RomBytes[DS1820_ADDR_LEN]; // declaration de la variable RomBytes[DS1820_ADDR_LEN]
+char FoundROM[9][8]; // Table of found ROM codes, 8 bytes for each
+
+
+/* -------------------------------------------------------------------------- */
+/* Low-Level Functions */
+/* -------------------------------------------------------------------------- */
+/*******************************************************************************
+ * FUNCTION: ow_reset
+ * PURPOSE: Initializes the DS1820 device.
+ *
+ * INPUT: -
+ * OUTPUT: -
+ * RETURN: FALSE if at least one device is on the 1-wire bus, TRUE otherwise
+ ******************************************************************************/
+bool ow_reset(void)
+{
+ bool presence;
+
+ /* reset pulse */
+ DQ.output();
+ DQ=0;
+ wait_us(DS1820_RST_PULSE);
+ DQ=1;
+
+ /* wait until pullup pull 1-wire bus to high */
+ wait_us(DS1820_PRESENCE_WAIT);
+
+ /* get presence pulse */
+ DQ.input();
+ presence=DQ.read();
+
+ wait_us(424);
+
+ return presence;
+}
+
+/*******************************************************************************
+ * FUNCTION: read_bit
+ * PURPOSE: Reads a single bit from the DS1820 device.
+ *
+ * INPUT: -
+ * OUTPUT: -
+ * RETURN: bool value of the bit which as been read form the DS1820
+ ******************************************************************************/
+bool read_bit(void)
+{
+ DQ.output();
+ DQ=0;
+ wait_us(DS1820_MSTR_BITSTART);
+ DQ.input();
+ DQ.read();
+ wait_us(DS1820_BITREAD_DLY);
+
+ return (DQ);
+}
+
+/*******************************************************************************
+ * FUNCTION: write_bit
+ * PURPOSE: Writes a single bit to the DS1820 device.
+ *
+ * INPUT: bBit value of bit to be written
+ * OUTPUT: -
+ * RETURN: -
+ ******************************************************************************/
+void write_bit(bool bBit)
+{
+ DQ.output();
+ DQ=0;
+ wait_us(DS1820_MSTR_BITSTART);
+
+ if (bBit != false) DQ=1;
+
+ wait_us(DS1820_BITWRITE_DLY);
+ DQ=1;
+
+}
+
+/*******************************************************************************
+ * FUNCTION: read_byte
+ * PURPOSE: Reads a single byte from the DS1820 device.
+ *
+ * INPUT: -
+ * OUTPUT: -
+ * RETURN: uint8 byte which has been read from the DS1820
+ ******************************************************************************/
+char read_byte(void)
+{
+ char i;
+ char value = 0;
+
+ for (i=0 ; i < 8; i++)
+ {
+ if ( read_bit() ) value |= (1 << i);
+ wait_us(120);
+ }
+ return(value);
+}
+
+/*******************************************************************************
+ * FUNCTION: write_byte
+ * PURPOSE: Writes a single byte to the DS1820 device.
+ *
+ * INPUT: val_u8 byte to be written
+ * OUTPUT: -
+ * RETURN: -
+ ******************************************************************************/
+void write_byte(char val_u8)
+{
+ char i;
+ char temp;
+
+ for (i=0; i < 8; i++) /* writes byte, one bit at a time */
+ {
+ temp = val_u8 >> i; /* shifts val right 'i' spaces */
+ temp &= 0x01; /* copy that bit to temp */
+ write_bit(temp); /* write bit in temp into */
+ }
+
+ wait_us(105);
+}
+/* -------------------------------------------------------------------------- */
+// One wire crc
+char ow_crc(char x)
+{
+ dowcrc = dscrc_table[dowcrc^x];
+ return dowcrc;
+}
+/* -------------------------------------------------------------------------- */
+/* API Interface */
+/* -------------------------------------------------------------------------- */
+
+/*******************************************************************************
+ * FUNCTION: DS1820_AddrDevice
+ * PURPOSE: Addresses a single or all devices on the 1-wire bus.
+ *
+ * INPUT: nAddrMethod use DS1820_CMD_MATCHROM to select a single
+ * device or DS1820_CMD_SKIPROM to select all
+ * OUTPUT: -
+ * RETURN: -
+ ******************************************************************************/
+void DS1820_AddrDevice(char nAddrMethod)
+{
+ char i;
+
+ if (nAddrMethod == DS1820_CMD_MATCHROM)
+ {
+ write_byte(DS1820_CMD_MATCHROM); /* address single devices on bus */
+ for (i = 0; i < DS1820_ADDR_LEN; i ++)
+ write_byte(RomBytes[i]);
+ }
+ else
+ write_byte(DS1820_CMD_SKIPROM); /* address all devices on bus */
+}
+
+/*******************************************************************************
+ * FUNCTION: Next
+ * PURPOSE: Finds next device connected to the 1-wire bus.
+ *
+ * INPUT: -
+ * OUTPUT: RomBytes[] ROM code of the next device
+ * RETURN: bool TRUE if there are more devices on the 1-wire
+ * bus, FALSE otherwise
+ ******************************************************************************/
+bool Next(void)
+{
+ char x;
+ char n;
+ char k = 1;
+ char m = 1;
+ char discrepMarker = 0;
+ bool g;
+ bool flag;
+ bool nxt = false;
+
+ /* init ROM address */
+ for (n=0; n < 8; n ++)
+ RomBytes[n] = 0x00;
+
+ flag = ow_reset(); /* reset the 1-wire */
+
+ if (flag || doneFlag) /* no device found */
+ {
+ lastDiscrep = 0; /* reset the search */
+ return false;
+ }
+
+ /* send search rom command */
+ write_byte(DS1820_CMD_SEARCHROM);
+
+ n = 0;
+ do
+ {
+ x = 0;
+
+ /* read bit */
+ if ( read_bit() == 1 ) x = 2;
+ wait_us(120);
+
+ /* read bit complement */
+ if ( read_bit() == 1 ) x |= 1;
+ wait_us(120);
+
+ /* description for values of x: */
+ /* 00 There are devices connected to the bus which have conflicting */
+ /* bits in the current ROM code bit position. */
+ /* 01 All devices connected to the bus have a 0 in this bit position. */
+ /* 10 All devices connected to the bus have a 1 in this bit position. */
+ /* 11 There are no devices connected to the 1-wire bus. */
+
+ /* if there are no devices on the bus */
+ if (x == 3) break;
+ else
+ {
+ /* devices have the same logical value at this position */
+ if (x > 0) g = (bool)(x >> 1);// get bit value
+ /* devices have confilcting bits in the current ROM code */
+ else
+ {
+ /* if there was a conflict on the last iteration */
+ if (m < lastDiscrep)
+ /* take same bit as in last iteration */
+ g = ( (RomBytes[n] & k) > 0 );
+ else
+ g = (m == lastDiscrep);
+
+ if (g == 0)
+ discrepMarker = m;
+ }
+
+ /* store bit in ROM address */
+ if (g ==1)
+ RomBytes[n] |= k;
+ else
+ RomBytes[n] &= ~k;
+
+ write_bit(g);
+
+ /* increment bit position */
+ m ++;
+
+ /* calculate next mask value */
+ k = k << 1;
+
+ /* check if this byte has finished */
+ if (k == 0)
+ {
+ ow_crc(RomBytes[n]); // Accumulate the crc
+ n ++; /* advance to next byte of ROM mask */
+ k = 1; /* update mask */
+ }
+ }
+ } while (n < DS1820_ADDR_LEN);
+
+
+ /* if search was unsuccessful then */
+ if ((m < 65) ||dowcrc)
+// if (m < 65 )
+ /* reset the last discrepancy to 0 */
+ lastDiscrep = 0;
+ else
+ {
+ /* search was successful */
+ lastDiscrep = discrepMarker;
+ doneFlag = (lastDiscrep == 0);
+
+ /* indicates search is not complete yet, more parts remain */
+ nxt = true;
+ }
+ return nxt;
+}
+
+/*******************************************************************************
+ * FUNCTION: First
+ * PURPOSE: Starts the device search on the 1-wire bus.
+ *
+ * INPUT: -
+ * OUTPUT: RomBytes[] ROM code of the first device
+ * RETURN: bool TRUE if there are more devices on the 1-wire
+ * bus, FALSE otherwise
+ ******************************************************************************/
+bool First(void)
+{
+ lastDiscrep = 0;
+ doneFlag = false;
+
+ return ( Next() );
+}
+/* -------------------------------------------------------------------------- */
+void FindDevices(void)
+{
+ char m;
+ if(!ow_reset())
+ {
+ if(First()) // Begins when at least one part found
+ {
+ numROMs = 0;
+ do
+ {
+ numROMs++;
+ for (m=0;m<8;m++)
+ {
+ FoundROM[numROMs-1][m] = RomBytes[m];
+ }
+ } while (Next()&&(numROMs<10)); // Continues until no additional
+ }
+ }
+
+}
+//******************************************************************************
+// Sends Match ROM command to bus then device address
+char Send_MatchRom(char actNumROM)
+{
+ char i;
+ if (ow_reset()) return false; // 0 if device present
+ write_byte(0x55); // Match ROM
+
+ for (i=0;i<8;i++)
+ {
+ write_byte(FoundROM[actNumROM][i]); // Send ROM code
+ }
+
+ return true;
+}
+//******************************************************************************
+void Read_ROMCode(void)
+{
+char n;
+char dat[9];
+
+ow_reset();
+write_byte(0x33);
+for (n=0;n<8;n++){dat[n]=read_byte();}
+
+pc.printf("\f%X%X%X%X\n%X%X%X%X",dat[0],dat[1],dat[2],dat[3],dat[4],dat[5],
+ dat[6],dat[7]);
+
+wait_ms(5000);
+}
+/*******************************************************************************
+ * FUNCTION: DS1820_WriteEEPROM
+ * PURPOSE: Writes to the DS1820 EEPROM memory (2 bytes available).
+ *
+ * INPUT: nTHigh high byte of EEPROM
+ * nTLow low byte of EEPROM
+ * OUTPUT: -
+ * RETURN: -
+ ******************************************************************************/
+void DS1820_WriteEEPROM(char nTHigh, char nTLow)
+{
+ /* --- write to scratchpad ----------------------------------------------- */
+ ow_reset(); // appel de la fonction ow_reset
+ DS1820_AddrDevice(DS1820_CMD_MATCHROM);
+ write_byte(DS1820_CMD_WRITESCRPAD); // debut conversion
+ write_byte(nTHigh);
+ write_byte(nTLow);
+ wait_us(10); // attendre 10ms
+ ow_reset(); // appel de la fonction ow_reset
+ DS1820_AddrDevice(DS1820_CMD_MATCHROM);
+ write_byte(DS1820_CMD_COPYSCRPAD); // start conversion
+ G__MOS_P=0; // "strong pullup"
+ wait_ms(10); // attendre 10 ms
+ G__MOS_P=1; // "strong pullup"
+}
+
+/*******************************************************************************
+ * FUNCTION: DS1820_GetTemp
+ * PURPOSE: Get temperature value from single DS1820 device.
+ *
+ * Scratchpad Memory Layout
+ * Byte Register
+ * 0 Temperature_LSB
+ * 1 Temperature_MSB
+ * 2 Temp Alarm High / User Byte 1
+ * 3 Temp Alarm Low / User Byte 2
+ * 4 Reserved
+ * 5 Reserved
+ * 6 Count_Remain
+ * 7 Count_per_C
+ * 8 CRC
+ *
+ * Temperature calculation for DS18S20 (Family Code 0x10):
+ * =======================================================
+ * (Count_per_C - Count_Remain)
+ * Temperature = temp_read - 0.25 + ----------------------------
+ * Count_per_C
+ *
+ * Where temp_read is the value from the temp_MSB and temp_LSB with
+ * the least significant bit removed (the 0.5C bit).
+ *
+ *
+ * Temperature calculation for DS18B20 (Family Code 0x28):
+ * =======================================================
+ * bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
+ * LSB 2^3 2^2 2^1 2^0 2^-1 2^-2 2^-3 2^-4
+ * bit15 bit14 bit13 bit12 bit3 bit2 bit1 bit0
+ * MSB S S S S S 2^6 2^5 2^4
+ *
+ * The temperature data is stored as a 16-bit sign-extended two�s
+ * complement number in the temperature register. The sign bits (S)
+ * indicate if the temperature is positive or negative: for
+ * positive numbers S = 0 and for negative numbers S = 1.
+ *
+ * RETURN: float
+ ******************************************************************************/
+float DS1820_GetTemp(void) //fonction capture de la temperature
+{
+ char i; //declaration de la variable i
+ char scrpad[DS1820_SCRPADMEM_LEN]; //declaration de la variable scrpad[DS1820_SCRPADMEM_LEN]
+ signed char temp_read; //declaration de la variable signe temp_read
+ float temperature; //declaration de la variable flotante temperature
+
+ /* --- start temperature conversion -------------------------------------- */
+ ow_reset();
+ DS1820_AddrDevice(DS1820_CMD_MATCHROM); /* address the device */
+ DQ.output(); //DQ en sortie
+ DQ=1; //DQ � 1
+ write_byte(DS1820_CMD_CONVERTTEMP); /* start conversion */
+ G__MOS_P=0; //"strong pullup"
+ /* wait for temperature conversion */
+ wait_ms(750); // attendre 0.75s
+ G__MOS_P=1; //"strong pullup"
+
+ /* --- read sratchpad ---------------------------------------------------- */
+ ow_reset();
+ DS1820_AddrDevice(DS1820_CMD_MATCHROM); /* address the device */
+ write_byte(DS1820_CMD_READSCRPAD); /* read scratch pad */
+
+ /* read scratch pad data */
+ for (i=0; i < DS1820_SCRPADMEM_LEN; i++) // boucle for : i=0 puis on l'incremante jusqu'a i < DS1820_SCRPADMEM_LEN
+ scrpad[i] = read_byte();
+
+ /* --- calculate temperature --------------------------------------------- */
+
+ if (RomBytes[0] == DS1820_FAMILY_CODE_DS18S20)
+ {
+/////////////////////// precision O,5 degC //////////////////////////////////////
+/*// temp = (signed int) make16(scrpad[1],scrpad[0]);
+ temp = (signed int) ((int)scrpad[1]<<8 | (int)scrpad[0]);
+ temperature =(float)temp/2;*/
+/////////////////////////////////////////////////////////////////////////////////
+
+////////////////////// precision O,1 deg ////////////////////////////////////////
+//...calcul....
+ temp_read=(signed char)(((int)scrpad[1]<<8 | (int)scrpad[0])>>1);
+ temperature=(float)(temp_read);
+ temperature = temperature + 0.75 - (float)(scrpad[6]/(float)scrpad[7]);
+////////////////////////////////////////////////////////////////////////////////
+ }
+ else//ds18b20
+ temperature =((float) (signed int)((int)scrpad[1]<<8 | (int)scrpad[0]))/16;
+
+ return (temperature);
+}
+//******************************************************************************
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Thu Apr 26 14:18:31 2012 +0000
@@ -0,0 +1,57 @@
+
+//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// //
+// Fonctionnement du programme du DS1820 //
+// //
+// //
+// 1) Pour commencer le MBED initial le bus 1-Wire c'est-à-dire : //
+// - MBED envoi une impulsion à 0 pendant 480µs minimum //
+// - Puis le DS1820 répond avec une impulsion à 0 de 60à 240µs. //
+// 2) On utilise la fonction «Search ROM [F0]» qui va permettre au MBED de récupérer tous les numéros //
+// de ROM des DS1820 et par la même occasion de savoir combien de DS1820 il y a sur le bus 1-Wire. //
+// 3) On fait un reset du bus 1-Wire on envoi le numéro de ROM « 0x10,0x65,0xF2,0x45,0x2,0x8,0x0,0xAE » //
+// pour communiquer avec le DS1820 désiré puis on utilise la fonction « Convert Temperature [44] », //
+// la valeur de la température est stocké dans le deuxième octet du scratchpad. //
+// 4) Puis on va lire dans le scratchpad la valeur de la température stockée dans la variable « temperature » //
+// prise par le DS1820. //
+// 5) Affichage de la variable « temperature » sur un HyperTerminal grâce à une liaison série. //
+// //
+//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+
+
+
+
+
+#include "mbed.h"
+#include "DS18S20.h"
+
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// //
+// Affichage de la temperature //
+// //
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+
+int main() /* debut du programme principal */
+{
+
+ float temperature; /* declaration de la variabble
+ flotante temperature */
+ G__MOS_P =1 ; /* initialisation du P-MOS */
+ FindDevices(); /* fonction cherchant le nombre de ds1820
+ et leur numero de serie */
+
+
+ while (true) /* boucle while infini */
+ {
+
+ if ( First() ) /* fonction if */
+ {
+ temperature = DS1820_GetTemp(); /* affectation du resultat de la temperature
+ a la variable temperature */
+ pc.printf("\t temp = % +.3g""\xb0""C \r",temperature); /* affichage de la temperature */
+ }
+ }
+}
\ No newline at end of file
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Thu Apr 26 14:18:31 2012 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed/builds/737756e0b479