/*********************************************************************************
Title: DS18X20-Functions via One-Wire-Bus
Author: Martin Thomas <eversmith@heizung-thomas.de>
http://www.siwawi.arubi.uni-kl.de/avr-projects
Software: avr-gcc 3.4.1 / avr-libc 1.0.4
Hardware: any AVR - tested with ATmega16/ATmega32 and 3 DS18B20
Partly based on code from Peter Dannegger and others
changelog:
20041124 - Extended measurements for DS18(S)20 contributed by Carsten Foss (CFO)
200502xx - function DS18X20_read_meas_single
20050310 - DS18x20 EEPROM functions (can be disabled to save flash-memory)
(DS18X20_EEPROMSUPPORT in ds18x20.h)
**********************************************************************************/
#include <avr/io.h>
#include "ds18x20.h"
#include "onewire.h"
#include "crc8.h"
#ifdef DS18X20_EEPROMSUPPORT
// for 10ms delay in copy scratchpad
#include "delay.h"
#endif
/*
convert raw value from DS18x20 to Celsius
input is:
- familycode fc (0x10/0x28 see header)
- scratchpad-buffer
output is:
- cel full celsius
- fractions of celsius in millicelsius*(10^-1)/625 (the 4 LS-Bits)
- subzero =0 positiv / 1 negativ
always returns DS18X20_OK
TODO invalid-values detection (but should be covered by CRC)
*/
uint8_t DS18X20_meas_to_cel( uint8_t fc, uint8_t *sp,
uint8_t* subzero, uint8_t* cel, uint8_t* cel_frac_bits)
{
uint16_t meas;
uint8_t i;
meas = sp[0]; // LSB
meas |= ((uint16_t)sp[1])<<8; // MSB
//meas = 0xff5e; meas = 0xfe6f;
// only work on 12bit-base
if( fc == DS18S20_ID ) { // 9 -> 12 bit if 18S20
/* Extended measurements for DS18S20 contributed by Carsten Foss */
meas &= (uint16_t) 0xfffe; // Discard LSB , needed for later extended precicion calc
meas <<= 3; // Convert to 12-bit , now degrees are in 1/16 degrees units
meas += (16 - sp[6]) - 4; // Add the compensation , and remember to subtract 0.25 degree (4/16)
}
// check for negative
if ( meas & 0x8000 ) {
*subzero=1; // mark negative
meas ^= 0xffff; // convert to positive => (twos complement)++
meas++;
}
else *subzero=0;
// clear undefined bits for B != 12bit
if ( fc == DS18B20_ID ) { // check resolution 18B20
i = sp[DS18B20_CONF_REG];
if ( (i & DS18B20_12_BIT) == DS18B20_12_BIT ) ;
else if ( (i & DS18B20_11_BIT) == DS18B20_11_BIT )
meas &= ~(DS18B20_11_BIT_UNDF);
else if ( (i & DS18B20_10_BIT) == DS18B20_10_BIT )
meas &= ~(DS18B20_10_BIT_UNDF);
else { // if ( (i & DS18B20_9_BIT) == DS18B20_9_BIT ) {
meas &= ~(DS18B20_9_BIT_UNDF);
}
}
*cel = (uint8_t)(meas >> 4);
*cel_frac_bits = (uint8_t)(meas & 0x000F);
return DS18X20_OK;
}
/* converts to decicelsius
input is ouput from meas_to_cel
returns absolute value of temperatur in decicelsius
i.e.: sz=0, c=28, frac=15 returns 289 (=28.9�C)
0 0 0
1 625 625 1
2 1250 250
3 1875 875 3
4 2500 500 4
5 3125 125
6 3750 750 6
7 4375 375
8 5000 0
9 5625 625 9
10 6250 250
11 6875 875 11
12 7500 500 12
13 8125 125
14 8750 750 14
15 9375 375 */
uint16_t DS18X20_temp_to_decicel(uint8_t subzero, uint8_t cel,
uint8_t cel_frac_bits)
{
uint16_t h;
uint8_t i;
uint8_t need_rounding[] = { 1, 3, 4, 6, 9, 11, 12, 14 };
h = cel_frac_bits*DS18X20_FRACCONV/1000;
h += cel*10;
if (!subzero) {
for (i=0; i<sizeof(need_rounding); i++) {
if ( cel_frac_bits == need_rounding[i] ) {
h++;
break;
}
}
}
return h;
}
/* compare temperature values (full celsius only)
returns -1 if param-pair1 < param-pair2
0 if ==
1 if > */
int8_t DS18X20_temp_cmp(uint8_t subzero1, uint16_t cel1,
uint8_t subzero2, uint16_t cel2)
{
int16_t t1 = (subzero1) ? (cel1*(-1)) : (cel1);
int16_t t2 = (subzero2) ? (cel2*(-1)) : (cel2);
if (t1<t2) return -1;
if (t1>t2) return 1;
return 0;
}
/* find DS18X20 Sensors on 1-Wire-Bus
input/ouput: diff is the result of the last rom-search
output: id is the rom-code of the sensor found */
void DS18X20_find_sensor(uint8_t *diff, uint8_t id[])
{
for (;;) {
*diff = ow_rom_search( *diff, &id[0] );
if ( *diff==OW_PRESENCE_ERR || *diff==OW_DATA_ERR ||
*diff == OW_LAST_DEVICE ) return;
if ( id[0] == DS18B20_ID || id[0] == DS18S20_ID ) return;
}
}
/* get power status of DS18x20
input : id = rom_code
returns: DS18X20_POWER_EXTERN or DS18X20_POWER_PARASITE */
uint8_t DS18X20_get_power_status(uint8_t id[])
{
uint8_t pstat;
ow_reset();
ow_command(DS18X20_READ_POWER_SUPPLY, id);
pstat=ow_bit_io(1); // pstat 0=is parasite/ !=0 ext. powered
ow_reset();
return (pstat) ? DS18X20_POWER_EXTERN:DS18X20_POWER_PARASITE;
}
/* start measurement (CONVERT_T) for all sensors if input id==NULL
or for single sensor. then id is the rom-code */
uint8_t DS18X20_start_meas( uint8_t with_power_extern, uint8_t id[])
{
ow_reset(); //**
if( ow_input_pin_state() ) { // only send if bus is "idle" = high
ow_command( DS18X20_CONVERT_T, id );
if (with_power_extern != DS18X20_POWER_EXTERN)
ow_parasite_enable();
return DS18X20_OK;
}
else {
#ifdef DS18X20_VERBOSE
uart_puts_P( "DS18X20_start_meas: Short Circuit !\r" );
#endif
return DS18X20_START_FAIL;
}
}
/* reads temperature (scratchpad) of sensor with rom-code id
output: subzero==1 if temp.<0, cel: full celsius, mcel: frac
in millicelsius*0.1
i.e.: subzero=1, cel=18, millicel=5000 = -18,5000�C */
uint8_t DS18X20_read_meas(uint8_t id[], uint8_t *subzero,
uint8_t *cel, uint8_t *cel_frac_bits)
{
uint8_t i;
uint8_t sp[DS18X20_SP_SIZE];
ow_reset(); //**
ow_command(DS18X20_READ, id);
for ( i=0 ; i< DS18X20_SP_SIZE; i++ ) sp[i]=ow_byte_rd();
if ( crc8( &sp[0], DS18X20_SP_SIZE ) )
return DS18X20_ERROR_CRC;
DS18X20_meas_to_cel(id[0], sp, subzero, cel, cel_frac_bits);
return DS18X20_OK;
}
/* reads temperature (scratchpad) of a single sensor (uses skip-rom)
output: subzero==1 if temp.<0, cel: full celsius, mcel: frac
in millicelsius*0.1
i.e.: subzero=1, cel=18, millicel=5000 = -18,5000�C */
uint8_t DS18X20_read_meas_single(uint8_t familycode, uint8_t *subzero,
uint8_t *cel, uint8_t *cel_frac_bits)
{
uint8_t i;
uint8_t sp[DS18X20_SP_SIZE];
ow_command(DS18X20_READ, NULL);
for ( i=0 ; i< DS18X20_SP_SIZE; i++ ) sp[i]=ow_byte_rd();
if ( crc8( &sp[0], DS18X20_SP_SIZE ) )
return DS18X20_ERROR_CRC;
DS18X20_meas_to_cel(familycode, sp, subzero, cel, cel_frac_bits);
return DS18X20_OK;
}
#ifdef DS18X20_EEPROMSUPPORT
uint8_t DS18X20_write_scratchpad( uint8_t id[],
uint8_t th, uint8_t tl, uint8_t conf)
{
ow_reset(); //**
if( ow_input_pin_state() ) { // only send if bus is "idle" = high
ow_command( DS18X20_WRITE_SCRATCHPAD, id );
ow_byte_wr(th);
ow_byte_wr(tl);
if (id[0] == DS18B20_ID) ow_byte_wr(conf); // config avail. on B20 only
return DS18X20_OK;
}
else {
#ifdef DS18X20_VERBOSE
uart_puts_P( "DS18X20_write_scratchpad: Short Circuit !\r" );
#endif
return DS18X20_ERROR;
}
}
uint8_t DS18X20_read_scratchpad( uint8_t id[], uint8_t sp[] )
{
uint8_t i;
ow_reset(); //**
if( ow_input_pin_state() ) { // only send if bus is "idle" = high
ow_command( DS18X20_READ, id );
for ( i=0 ; i< DS18X20_SP_SIZE; i++ ) sp[i]=ow_byte_rd();
return DS18X20_OK;
}
else {
#ifdef DS18X20_VERBOSE
uart_puts_P( "DS18X20_read_scratchpad: Short Circuit !\r" );
#endif
return DS18X20_ERROR;
}
}
uint8_t DS18X20_copy_scratchpad( uint8_t with_power_extern,
uint8_t id[] )
{
ow_reset(); //**
if( ow_input_pin_state() ) { // only send if bus is "idle" = high
ow_command( DS18X20_COPY_SCRATCHPAD, id );
if (with_power_extern != DS18X20_POWER_EXTERN)
ow_parasite_enable();
delay_ms(DS18X20_COPYSP_DELAY); // wait for 10 ms
if (with_power_extern != DS18X20_POWER_EXTERN)
ow_parasite_disable();
return DS18X20_OK;
}
else {
#ifdef DS18X20_VERBOSE
uart_puts_P( "DS18X20_copy_scratchpad: Short Circuit !\r" );
#endif
return DS18X20_START_FAIL;
}
}
uint8_t DS18X20_recall_E2( uint8_t id[] )
{
ow_reset(); //**
if( ow_input_pin_state() ) { // only send if bus is "idle" = high
ow_command( DS18X20_RECALL_E2, id );
// TODO: wait until status is "1" (then eeprom values
// have been copied). here simple delay to avoid timeout
// handling
delay_ms(DS18X20_COPYSP_DELAY);
return DS18X20_OK;
}
else {
#ifdef DS18X20_VERBOSE
uart_puts_P( "DS18X20_recall_E2: Short Circuit !\r" );
#endif
return DS18X20_ERROR;
}
}
#endif
/*----------- start of "debug-functions" ---------------*/
#ifdef DS18X20_VERBOSE
/* functions for debugging-output - undef DS18X20_VERBOSE in .h
if you run out of program-memory */
#include <string.h>
#include "uart.h"
void DS18X20_uart_put_temp(const uint8_t subzero,
const uint8_t cel, const uint8_t cel_frac_bits)
{
uint8_t buffer[sizeof(int)*8+1];
int i;
uart_putc((subzero)?'-':'+');
uart_puti((int)cel);
uart_puts_P(".");
itoa(cel_frac_bits
*DS18X20_FRACCONV
,buffer
,10); for (i
=0;i
<4-strlen(buffer
);i
++) uart_puts_P
("0"); uart_puts(buffer);
uart_puts_P(" C");
}
void DS18X20_show_id_uart( uint8_t *id, size_t n )
{
size_t i;
for( i = 0; i < n; i++ ) {
if ( i == 0 ) uart_puts_P( "FC:" );
else if ( i == n-1 ) uart_puts_P( "CRC:" );
if ( i == 1 ) uart_puts_P( "SN: " );
uart_puthex_byte(id[i]);
uart_puts_P(" ");
if ( i == 0 ) {
if ( id[0] == DS18S20_ID ) uart_puts_P ("(18S)");
else if ( id[0] == DS18B20_ID ) uart_puts_P ("(18B)");
else uart_puts_P ("( ? )");
}
}
if ( crc8( id, OW_ROMCODE_SIZE) )
uart_puts_P( " CRC FAIL " );
else
uart_puts_P( " CRC O.K. " );
}
void show_sp_uart( uint8_t *sp, size_t n )
{
size_t i;
uart_puts_P( "SP:" );
for( i = 0; i < n; i++ ) {
if ( i == n-1 ) uart_puts_P( "CRC:" );
uart_puthex_byte(sp[i]);
uart_puts_P(" ");
}
}
/* verbose output rom-search follows read-scratchpad in one loop */
uint8_t DS18X20_read_meas_all_verbose( void )
{
uint8_t id[OW_ROMCODE_SIZE], sp[DS18X20_SP_SIZE], diff;
uint8_t i;
uint16_t meas;
uint8_t subzero, cel, cel_frac_bits;
for( diff = OW_SEARCH_FIRST; diff != OW_LAST_DEVICE; )
{
diff = ow_rom_search( diff, &id[0] );
if( diff == OW_PRESENCE_ERR ) {
uart_puts_P( "No Sensor found\r" );
return OW_PRESENCE_ERR;
}
if( diff == OW_DATA_ERR ) {
uart_puts_P( "Bus Error\r" );
return OW_DATA_ERR;
}
DS18X20_show_id_uart( id, OW_ROMCODE_SIZE );
if( id[0] == DS18B20_ID || id[0] == DS18S20_ID ) { // temperature sensor
uart_putc ('\r');
ow_byte_wr( DS18X20_READ ); // read command
for ( i=0 ; i< DS18X20_SP_SIZE; i++ )
sp[i]=ow_byte_rd();
show_sp_uart( sp, DS18X20_SP_SIZE );
if ( crc8( &sp[0], DS18X20_SP_SIZE ) )
uart_puts_P( " CRC FAIL " );
else
uart_puts_P( " CRC O.K. " );
uart_putc ('\r');
meas = sp[0]; // LSB Temp. from Scrachpad-Data
meas |= (uint16_t) (sp[1] << 8); // MSB
uart_puts_P(" T_raw=");
uart_puthex_byte((uint8_t)(meas>>8));
uart_puthex_byte((uint8_t)meas);
uart_puts_P(" ");
if( id[0] == DS18S20_ID ) { // 18S20
uart_puts_P( "S20/09" );
}
else if ( id[0] == DS18B20_ID ) { // 18B20
i=sp[DS18B20_CONF_REG];
if ( (i & DS18B20_12_BIT) == DS18B20_12_BIT ) {
uart_puts_P( "B20/12" );
}
else if ( (i & DS18B20_11_BIT) == DS18B20_11_BIT ) {
uart_puts_P( "B20/11" );
}
else if ( (i & DS18B20_10_BIT) == DS18B20_10_BIT ) {
uart_puts_P( " B20/10 " );
}
else { // if ( (i & DS18B20_9_BIT) == DS18B20_9_BIT ) {
uart_puts_P( "B20/09" );
}
}
uart_puts_P(" ");
DS18X20_meas_to_cel(id[0], sp, &subzero, &cel, &cel_frac_bits);
DS18X20_uart_put_temp(subzero, cel, cel_frac_bits);
uart_puts("\r");
} // if meas-sensor
} // loop all sensors
uart_puts_P( "\r" );
return DS18X20_OK;
}
#endif
/*----------- end of "debug-functions" ---------------*/