Diff: onewire.cpp

Revision:

0:1449f126b241

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/onewire.cpp	Sun Mar 03 01:41:51 2013 +0000
@@ -0,0 +1,313 @@
+/**
+* @file onewire.c
+* @brief library 1-Wire(www.maxim-ic.com)
+* @author Maciej Rajtar (Published 10 May 2010 www.mbed.org)
+* @author Frederic BLANC
+*/
+#include "mbed.h"
+#include "onewire.h"
+#include "DS18X20.h"
+#include "crc8.h"
+
+DigitalInOut ow_pin(ONEWIRE_PIN);
+
+/**
+*     @brief PUL-UP bus OW
+*    @return OW_OK
+*     @date 20/06/2011
+*/
+uint8_t ow_PullUp(void)
+{
+    ow_pin.mode(PullUp); //PULL-UP bus OW
+return OW_OK;
+}
+/**
+*     @brief search_sensors
+*    @param  [out] nSensors number of device onewire
+*    @param  [out] gSensorIDs[][] array of id romcode
+*    @return OW_OK or OW_PRESENCE_ERR or OW_DATA_ERR
+*     @date 20/06/2011
+*/
+uint8_t search_sensors(uint8_t *nSensors,uint8_t *gSensorIDs ) {
+    uint8_t i;
+    uint8_t id[OW_ROMCODE_SIZE];
+    uint8_t diff;
+    printf( "Scanning Bus\n" );
+    diff = OW_SEARCH_FIRST;
+    for (*nSensors = 0 ; (diff != OW_LAST_DEVICE) && (*nSensors < MAXSENSORS) ;++(*nSensors) ) {
+        ow_find_sensor( &diff, &id[0] );
+        if ( diff == OW_PRESENCE_ERR ) {
+            printf( "No Sensor found\n" );
+            return diff;
+        }
+        if ( diff == OW_DATA_ERR ) {
+            printf( "Bus Error\n" );
+            return diff;
+        }
+        for (i=0;i<OW_ROMCODE_SIZE;i++)
+            gSensorIDs[(*nSensors)*OW_ROMCODE_SIZE+i]=id[i];
+
+    }
+    return OW_OK;
+}
+/**
+*     @brief show_id
+*    @param  [in] id[] = rom_code
+*    @param  [in] n number of id[n]
+*    @param  [out] text id
+*    @return OW_OK or OW_ERROR_CRC
+*     @date 20/06/2011
+*/
+uint8_t ow_show_id( uint8_t id[], size_t n ,char *text) {
+    size_t i;
+    char hex[4];
+    sprintf(text,"");
+    
+    for ( i = 0; i < n; i++ ) {
+        if ( i == 0 ) strcat(text, " FC: " );
+        else if ( i == n-1 ) strcat(text, "CRC: " );
+        if ( i == 1 ) strcat(text, " SN: " );
+        sprintf(hex,"%2.2X ",id[i]);
+        strcat(text,hex);
+        if ( i == 0 ) {
+            if ( id[0] == DS18S20_ID ) strcat(text,"(18S)");
+            else if ( id[0] == DS18B20_ID ) strcat(text,"(18B)");
+            else strcat(text,"( ? )");
+        }
+    }
+    if ( crc8( id, OW_ROMCODE_SIZE) )
+        return OW_ERROR_CRC;
+    return OW_OK;
+}
+
+/**
+*     @brief test pin onewire bus
+*    @return etat pin ow
+*     @date 20/06/2011
+*/
+uint8_t ow_test_pin (void){
+    if (ow_pin)
+        return 1;
+return 0;   
+}
+/**
+*     @brief onewire reset bus
+*    @return pin ow or OW_SHORT_CIRCUIT
+*     @date 20/06/2011
+*/
+uint8_t ow_reset(void) { // reset.  Should improve to act as a presence pulse
+    uint8_t err;
+
+    ow_pin.output();
+    ow_pin = 0;     // bring low for 500 us
+    wait_us(500);
+    ow_pin.input();
+    wait_us(60);
+    err = ow_pin;
+    wait_us(240);
+    if ( ow_pin == 0 )    {    // short circuit
+        err = OW_SHORT_CIRCUIT;
+    }
+    return err;
+}
+
+/**
+*     @brief read write onewire
+*    @param  [in/out] b data
+*    @return data
+*     @date 20/06/2011
+*/
+uint8_t ow_bit_io( uint8_t b ) {
+
+    ow_pin.output(); // drive bus low
+    ow_pin = 0;
+    wait_us(1); // Recovery-Time wuffwuff was 1
+    
+    if ( b ) 
+        ow_pin.input(); // if bit is 1 set bus high (by ext. pull-up)
+    //  delay was 15uS-1 see comment above
+    wait_us(15-1);
+    if ( ow_pin == 0 ) b = 0; // sample at end of read-timeslot
+    wait_us(60-15);
+    ow_pin.input();
+    return b;
+}
+
+/**
+*     @brief byte write on onewire
+*    @param  [in] b data
+*    @return data
+*     @date 20/06/2011
+*/
+uint8_t ow_byte_wr( uint8_t b ) {
+    uint8_t i = 8, j;
+
+    do {
+        j = ow_bit_io( b & 1 );
+        b >>= 1;
+        if ( j )
+            b |= 0x80;
+    } while ( --i );
+    return b;
+}
+
+/**
+*     @brief byte read on onewire
+*    @param  [in] uint8_t b
+*    @return 
+*     @date 20/06/2011
+*/
+uint8_t ow_byte_rd( void ) {
+    // read by sending 0xff (a dontcare?)
+    return ow_byte_wr( 0xFF );
+}
+
+
+/**
+*     @brief search romcode
+*    @param  [in] uint8_t diff
+*    @param  [out] id romcode
+*    @return next_diff or OW_LAST_DEVICE or OW_DATA_ERR or OW_PRESENCE_ERR
+*     @date 20/06/2011
+*/
+uint8_t ow_rom_search( uint8_t diff, uint8_t id[] ) {
+    uint8_t i, j, next_diff;
+    uint8_t b;
+
+    if ( ow_reset() )
+        return OW_PRESENCE_ERR;    // error, no device found
+    ow_byte_wr( OW_SEARCH_ROM );            // ROM search command
+    next_diff = OW_LAST_DEVICE;            // unchanged on last device
+    i = OW_ROMCODE_SIZE * 8;                    // 8 bytes
+    do {
+        j = 8;                                // 8 bits
+        do {
+            b = ow_bit_io( 1 );                // read bit
+            if ( ow_bit_io( 1 ) ) {            // read complement bit
+                if ( b )                    // 11
+                    return OW_DATA_ERR;        // data error
+            } else {
+                if ( !b ) {                    // 00 = 2 devices
+                    if ( diff > i || ((*id & 1) && diff != i) ) {
+                        b = 1;                // now 1
+                        next_diff = i;        // next pass 0
+                    }
+                }
+            }
+            ow_bit_io( b );                 // write bit
+            *id >>= 1;
+            if ( b ) 
+                *id |= 0x80;            // store bit
+            --i;
+        } while ( --j );
+        id++;                                // next byte
+    } while ( i );
+    return next_diff;                // to continue search
+}
+
+/**
+*     @brief write command
+*    @param  [in] command
+*    @param  [in] id romcode
+*     @date 20/06/2011
+*/
+uint8_t ow_command( uint8_t command, uint8_t id[] ) {
+    uint8_t i;
+
+    ow_reset();
+    if ( id ) {
+        ow_byte_wr( OW_MATCH_ROM );            // to a single device
+        i = OW_ROMCODE_SIZE;
+        do {
+            ow_byte_wr( *id );
+            ++id;
+        } while ( --i );
+    } else {
+        ow_byte_wr( OW_SKIP_ROM );            // to all devices
+    }
+    ow_byte_wr( command );
+    return 0;
+}
+/**
+*     @brief parasite enable
+*     @date 20/06/2011
+*/
+uint8_t ow_parasite_enable(void) {
+    ow_pin.output();
+    ow_pin = 1;
+    return 0;
+}
+/**
+*     @brief parasite disable
+*     @date 20/06/2011
+*/
+uint8_t ow_parasite_disable(void) {
+
+    ow_pin.input();
+    return 0;
+}
+
+
+/**
+*     @brief find Sensors on 1-Wire-Bus
+*    @param  [in/out] diff is the result of the last rom-search
+*    @param  [out] is the rom-code of the sensor found
+*    @return  OW_OK or OW_ERROR 
+*/
+uint8_t ow_find_sensor(uint8_t *diff, uint8_t id[]) {
+    for (;;) 
+    {
+        *diff = ow_rom_search( *diff, &id[0] );
+        if ( *diff==OW_PRESENCE_ERR)
+            return OW_ERROR;
+        if ( *diff==OW_DATA_ERR )
+            return OW_ERROR;
+        if ( *diff == OW_LAST_DEVICE )
+            return OW_OK ;
+        if ( id[0] == DS18B20_ID || id[0] == DS18S20_ID ) 
+            return OW_OK ;
+    }
+}
+
+/**
+*     @brief output byte d (least sig bit first)
+*    @param  [in] d output byte (least sig bit first)
+*    @return  OW_OK 
+*/
+uint8_t OneWireOutByte(uint8_t d) { // output byte d (least sig bit first).
+    for (int n=8; n!=0; n--) {
+        if ((d & 0x01) == 1) { // test least sig bit
+            ow_pin.output();
+            ow_pin = 0;
+            wait_us(5);
+            ow_pin.input();
+            wait_us(80);
+        } else {
+            ow_pin.output();
+            ow_pin = 0;
+            wait_us(80);
+            ow_pin.input();
+        }
+        d=d>>1; // now the next bit is in the least sig bit position.
+    }
+    return OW_OK;
+}
+/**
+*     @brief read byte, least sig byte first
+*    @return  byte, least sig byte first 
+*/
+uint8_t OneWireInByte(void) { // read byte, least sig byte first
+    uint8_t d = 0, b;
+    for (int n=0; n<8; n++) {
+        ow_pin.output();
+        ow_pin = 0;
+        wait_us(5);
+        ow_pin.input();
+        wait_us(5);
+        b =ow_pin;
+        wait_us(50);
+        d = (d >> 1) | (b << 7); // shift d to right and insert b in most sig bit position
+    }
+    return d;
+}
+