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dallas onewire primitives library and ds1822 driver code

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jds-pic

Joined: 17 Sep 2003
Posts: 205

dallas onewire primitives library and ds1822 driver code

Posted: Fri Jun 04, 2004 9:54 am

http://losdos.dyndns.org:8080/public/onewire/lib-onewire.html

Code:

// onewire library, for dallas onewire devices
// currently includes:
// - generic onewire functions (init, readbyte, sendbyte, crc, etc.)
// - ds1822 dallas-semi econo-thermometer

// (C) copyright 2003 j.d.sandoz / jds-pic !at! losdos.dyndns.org

// released under the GNU GENERAL PUBLIC LICENSE (GPL)
// refer to http://www.gnu.org/licenses/gpl.txt

// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

// ds1822 scratchpad registers
#define DS1822_SP_TLSB 0
#define DS1822_SP_TMSB 1
#define DS1822_SP_HLIM 2
#define DS1822_SP_LLIM 3
#define DS1822_SP_CFG 4
#define DS1822_SP_RES0 5
#define DS1822_SP_RES1 6
#define DS1822_SP_RES2 7
#define DS1822_SP_CRC 8

// ds1822 rom registers
#define DS1822_ROM_DEVTYPE 0
#define DS1822_ROM_SERIAL1 1
#define DS1822_ROM_SERIAL2 2
#define DS1822_ROM_SERIAL3 3
#define DS1822_ROM_SERIAL4 4
#define DS1822_ROM_SERIAL5 5
#define DS1822_ROM_SERIAL6 6
#define DS1822_ROM_CRC 7

// ds1822 command set
#define DS1822_CMD_READROM 0x33
#define DS1822_CMD_SKIPROM 0xCC
#define DS1822_CMD_CONVERTTEMP 0x44
#define DS1822_CMD_WRITESCRATCHPAD 0x4E
#define DS1822_CMD_READSCRATCHPAD 0xBE
#define DS1822_CMD_COPYSCRATCHPAD 0x48

// note that not all applications need to disable interrupts when
// performing onewire transactions. but, if unmasked interrupts
// cause onewire timing violations, returned data will be suspect
// or there may be other, hard-to-reproduce problems.

void onewire_disable_interrupts(int disable) {
if (disable)
disable_interrupts(GLOBAL);
else
enable_interrupts(GLOBAL);
}

short int onewire_init_with_error_check() {
onewire_disable_interrupts(TRUE);
output_low(ONE_WIRE_PIN);
delay_us( 500 ); // pull 1-wire low for reset pulse
output_float(ONE_WIRE_PIN); // float 1-wire high
delay_us( 5 ); // allow pin to stabilize
if (!input(ONE_WIRE_PIN)) {
onewire_disable_interrupts(FALSE);
return ( FALSE ); // error (1-wire leads shorted)
}
delay_us( 80 ); // wait for presence pulse, allowing for device variation
if (input(ONE_WIRE_PIN)) {
onewire_disable_interrupts(FALSE);
return ( FALSE ); // error (no 1-wire devices present)
}
delay_us( 420 ); // wait-out remaining initialisation window.
output_float(ONE_WIRE_PIN);
//printf(debug_putc,"<>ok >onewire_init\n\r");
onewire_disable_interrupts(FALSE);
return ( TRUE ); // device(s) present and initialised.
}

void onewire_init() { // OK if just using a single permanently connected device
onewire_disable_interrupts(TRUE);
output_low(ONE_WIRE_PIN);
delay_us( 500 ); // pull 1-wire low for reset pulse
output_float(ONE_WIRE_PIN); // float 1-wire high
delay_us( 80 ); // wait for presence pulse, allowing for device variation
delay_us( 420 ); // wait-out remaining initialisation window.
output_float(ONE_WIRE_PIN);
onewire_disable_interrupts(FALSE);
}

void onewire_sendbyte(int data) {
int count;
//static int debugS;
//printf(debug_putc,"0x%x >onewire_sendbyte(%u)\n\r",data,debugS++);
onewire_disable_interrupts(TRUE);
for (count=0; count<8; ++count) {
output_low(ONE_WIRE_PIN);
delay_us( 2 ); // pull 1-wire low to initiate write time-slot.
output_bit(ONE_WIRE_PIN, shift_right(&data,1,0)); // set output bit on 1-wire
delay_us( 60 ); // wait until end of write slot.
output_float(ONE_WIRE_PIN); // set 1-wire high again,
delay_us( 2 ); // for more than 1us minimum.
}
onewire_disable_interrupts(FALSE);
}

int onewire_readbyte() {
int count, data;
//static int debugR;
onewire_disable_interrupts(TRUE);
for (count=0; count<8; ++count) {
output_low(ONE_WIRE_PIN);
delay_us( 2 ); // pull 1-wire low to initiate read time-slot.
output_float(ONE_WIRE_PIN); // now let 1-wire float high,
delay_us( 8 ); // let device state stabilise,
shift_right(&data,1,input(ONE_WIRE_PIN)); // and load result.
delay_us( 120 ); // wait until end of read slot.
}
//printf(debug_putc,"0x%x >onewire_readbyte(%u)\n\r",data,debugR++);
onewire_disable_interrupts(FALSE);
return( data );
}

int onewire_ds1822_read_scratchpad(int field) { /* returns config bitfield */
int data[9];

onewire_init();
onewire_sendbyte(DS1822_CMD_SKIPROM);
onewire_sendbyte(DS1822_CMD_READSCRATCHPAD);

data[DS1822_SP_TLSB]=onewire_readbyte(); // 0 Tlsb
data[DS1822_SP_TMSB]=onewire_readbyte(); // 1 Tmsb
data[DS1822_SP_HLIM]=onewire_readbyte(); // 2 Thlim
data[DS1822_SP_LLIM]=onewire_readbyte(); // 3 Tllim
data[DS1822_SP_CFG]=onewire_readbyte(); // 4 Config
data[DS1822_SP_RES0]=onewire_readbyte(); // 5 RES0
data[DS1822_SP_RES1]=onewire_readbyte(); // 6 RES1
data[DS1822_SP_RES2]=onewire_readbyte(); // 7 RES2
data[DS1822_SP_CRC]=onewire_readbyte(); // 8 CRC

if (field > 8) {
//printf(debug_putc,"ERR! >scratchpad field 0x%x out of range (ds1822)\n\r",field);
return(0);
}
else {
//printf(debug_putc,"0x%x >scratchpad field 0x%x (ds1822)\n\r",data[field],field);
return(data[field]);
}
}

int onewire_ds1822_read_rom(int field) { /* rtns ROM info, one byte at a time */
int data[8];

if (!onewire_init_with_error_check())
return (0);
onewire_sendbyte(DS1822_CMD_READROM);

data[DS1822_ROM_DEVTYPE]=onewire_readbyte(); // 0 family code
data[DS1822_ROM_SERIAL1]=onewire_readbyte(); // 1 serial number LSB
data[DS1822_ROM_SERIAL2]=onewire_readbyte(); // 2 serial number
data[DS1822_ROM_SERIAL3]=onewire_readbyte(); // 3 serial number
data[DS1822_ROM_SERIAL4]=onewire_readbyte(); // 4 serial number
data[DS1822_ROM_SERIAL5]=onewire_readbyte(); // 5 serial number
data[DS1822_ROM_SERIAL6]=onewire_readbyte(); // 6 serial number MSB
data[DS1822_ROM_CRC]=onewire_readbyte(); // 7 CRC

if (field > 7) {
//printf(debug_putc,"ERR! >rom field 0x%x out of range (ds1822)\n\r",field);
return(0);
}
else {
//printf(debug_putc,"0x%x >rom field 0x%x (ds1822)\n\r",data[field],field);
return(data[field]);
}
}

int onewire_crc(int oldcrc, int newbyte) {
// see http://pdfserv.maxim-ic.com/arpdf/AppNotes/app27.pdf
int shift_reg, data_bit, sr_lsb, fb_bit, j;

shift_reg=oldcrc;
for(j=0; j<8; j++) { // for each bit
data_bit = (newbyte >> j) & 0x01;
sr_lsb = shift_reg & 0x01;
fb_bit = (data_bit ^ sr_lsb) & 0x01;
shift_reg = shift_reg >> 1;
if (fb_bit)
shift_reg = shift_reg ^ 0x8c;
}
return(shift_reg);
}

int onewire_ds1822_set_temperature_resolution(int resolution) { /* set up for nbit resolution */
int resolution_cfgfield;

if ((resolution < 9) || (resolution > 12))
resolution=9;

resolution_cfgfield=((resolution-9)<<5); // see DS1822 datasheet page 7

if (!onewire_init_with_error_check())
return (0);
onewire_sendbyte(DS1822_CMD_SKIPROM);
onewire_sendbyte(DS1822_CMD_WRITESCRATCHPAD);

onewire_sendbyte(0b01111101); // set max TH threshold (125'C)
onewire_sendbyte(0b11001001); // set min TL threshold (-55'C)
onewire_sendbyte(resolution_cfgfield); // Temp resolution, set to nbit

onewire_init(); // reset
onewire_sendbyte(DS1822_CMD_SKIPROM);
onewire_sendbyte(DS1822_CMD_COPYSCRATCHPAD);
delay_ms(15); // allow time for flash memory write.

return( (onewire_ds1822_read_scratchpad(DS1822_SP_CFG) & 0b01100000)>>5 );
}

int onewire_ds1822_read_temp_c_lite() { /* 0 to 125'C byte rtnd, nonparasitic mode */
int temperatureLSB, temperatureMSB, config, delaymult;

config=((onewire_ds1822_read_scratchpad(DS1822_SP_CFG) & 0b01100000)>>5);
// each addn'l resolution bit needs twice the base conversion time!
if (!onewire_init_with_error_check())
return (0);
onewire_sendbyte(DS1822_CMD_SKIPROM);
onewire_sendbyte(DS1822_CMD_CONVERTTEMP);

delaymult=(1<<config);
//printf(debug_putc,"0x%x >delay_mult (ds1822)\n\r",delaymult);

while (delaymult--)
delay_ms(100); // allow worst case time for temp. conversion.

temperatureLSB = onewire_ds1822_read_scratchpad(DS1822_SP_TLSB);
temperatureMSB = onewire_ds1822_read_scratchpad(DS1822_SP_TMSB);

if (temperatureMSB & 0b11111000) // if temp is negative rtn 0
return(0);
else { // else rtn the positive temp
temperatureLSB=((temperatureLSB & 0b11110000)>>4);
temperatureMSB=((temperatureMSB & 0b00000111)<<4);
}
return(temperatureMSB | temperatureLSB); // OR msb&lsb
}

Last edited by jds-pic on Sun Jan 23, 2011 5:47 pm; edited 1 time in total

jds-pic

Joined: 17 Sep 2003
Posts: 205

Posted: Sat Jun 12, 2004 7:13 am

someone asked me for example code...

for temperature measurements WITH A SINGLE PERMANENTLY ATTACHED DS1822 onewire device...
in your main() or other calling function:

Code:

int temperature;

if (int onewire_init_with_error_check()) {
// set the number of bits of resolution on the ds1822.
// note that this affects the conversion time,
// RTFM and see the called function.
onewire_ds1822_set_temperature_resolution(9);

// read the temperature from the ds1822.
// note that the returned value is in deg C,
// and the "lite" function returns only positive temps.
temperature = onewire_ds1822_read_temp_c_lite();
}
else
printf("onewire device not found");

here's a little snippet that shows how to get the 48bit unique serial number from the DS1822...

Code:

printf(lcd_putc,"Widget / Ver%04Lx", (int16)FW_VERSION);
printf(lcd_putc,"Ser ");
if (onewire_init_with_error_check()) {
for (loop=6; loop>=1; loop--)
printf(lcd_putc,"%x",onewire_ds1822_read_rom(loop));
}

and then another snippet that shows how to retrieve the burned in CRC and compute same from the ROM data...

Code:

crc=0;
if (onewire_init_with_error_check()) {
for (loop=0;loop<7;loop++) // crc check to see if we are reading onewire net correctly
crc=onewire_crc(crc,onewire_ds1822_read_rom(loop));
printf(serial_putc,"\r\nchk: 0x%x/",onewire_ds1822_read_rom(DS1822_ROM_DEVTYPE)); // 1st ROM byte = device type
printf(serial_putc,"0x%x/0x%x\r\n",onewire_ds1822_read_rom(DS1822_ROM_CRC),crc);
}

glavic

Joined: 13 Jul 2005
Posts: 7

Posted: Wed Jul 13, 2005 6:34 am

function onewire_readbyte()

Code:

int onewire_readbyte() {
int count, data;
//static int debugR;
onewire_disable_interrupts(TRUE);
for (count=0; count<8; ++count) {
output_low(ONE_WIRE_PIN);
delay_us( 2 ); // pull 1-wire low to initiate read time-slot.
output_float(ONE_WIRE_PIN); // now let 1-wire float high,
delay_us( 8 ); // let device state stabilise,
shift_right(&data,1,input(ONE_WIRE_PIN)); // and load result.
delay_us( 120 ); // wait until end of read slot.
}
//printf(debug_putc,"0x%x >onewire_readbyte(%u)\n\r",data,debugR++);
onewire_disable_interrupts(FALSE);
return( data );
}

Why is there 120us delay in readybyte function ?
The read-time slots is minimum 60us + minimum 1us recovery time between slots, so 80us is enough. I am using 66us read-time slots. You should take samples between 15us and 30us. I am getting sample in 18us.

edited >

Code:

int onewire_read_byte ()
{
int count, data;

onewire_disable_interrupts(TRUE);

for (count=0; count < 8; ++count)
{
   output_low(ONE_WIRE_PIN);
   delay_us(2);
   output_float(ONE_WIRE_PIN);
   delay_us(18);
   shift_right(&data, 1, input(ONE_WIRE_PIN));
   delay_us(44);
}

onewire_disable_interrupts(FALSE);
return(data);
}

function onewire_ds1822_read_temp_c_lite()

Code:

.
.
.
temperatureLSB = onewire_ds1822_read_scratchpad(DS1822_SP_TLSB);
temperatureMSB = onewire_ds1822_read_scratchpad(DS1822_SP_TMSB);
.
.

Here you read the scratchpad twice. Why?

edited >

Code:

void onewire_ds1822_read_scratchpad(int *data)
{
onewire_init();
onewire_sendbyte(DS1822_CMD_SKIPROM);
onewire_sendbyte(DS1822_CMD_READSCRATCHPAD);

data[DS1822_SP_TLSB]=onewire_readbyte(); // 0 Tlsb
data[DS1822_SP_TMSB]=onewire_readbyte(); // 1 Tmsb
data[DS1822_SP_HLIM]=onewire_readbyte(); // 2 Thlim
data[DS1822_SP_LLIM]=onewire_readbyte(); // 3 Tllim
data[DS1822_SP_CFG]=onewire_readbyte(); // 4 Config
data[DS1822_SP_RES0]=onewire_readbyte(); // 5 RES0
data[DS1822_SP_RES1]=onewire_readbyte(); // 6 RES1
data[DS1822_SP_RES2]=onewire_readbyte(); // 7 RES2
data[DS1822_SP_CRC]=onewire_readbyte(); // 8 CRC
}

so now you can call this function once and you will get all the scratchpad registers in array >>

Code:

int onewire_ds1822_read_temp_c_lite() { /* 0 to 125'C byte rtnd, nonparasitic mode */
int temperatureLSB, temperatureMSB, config, delaymult, scratchpad[9];
.
.
.
onewire_ds1822_read_scratchpad(scratchpad);

temperatureLSB = scratchpad[0];
temperatureMSB = scratchpad[1];
.
.
.
}

jds-pic

Joined: 17 Sep 2003
Posts: 205

Re: dallas onewire primitives library and ds1822 driver code

Posted: Wed Jan 11, 2006 2:42 pm

Code:

int onewire_ds1822_read_temp_c_lite() { /* 0 to 125'C byte rtnd, nonparasitic mode */
int temperatureLSB, temperatureMSB, config, delaymult;
<...snip...>
if (temperatureMSB & 0b11111000) // if temp is negative rtn 0
return(0);
else { // else rtn the positive temp
temperatureLSB=((temperatureLSB & 0b11110000)>>4);
temperatureMSB=((temperatureMSB & 0b00000111)<<4);
}
return(temperatureMSB | temperatureLSB); // OR msb&lsb
}

for dealing with negative temperatures, see this thread:
http://www.ccsinfo.com/forum/viewtopic.php?t=25630

jds-pic

ckielstra

Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands


Posted: Wed Mar 08, 2006 8:12 am

A more efficient implementation of the CRC calculation can be found in http://www.ccsinfo.com/forum/viewtopic.php?p=60194

acidice333

Joined: 14 Oct 2006
Posts: 33


Posted: Sun Dec 24, 2006 4:25 am

Now I know this is for just a single, but does anybody have a modified code for multiple?

jds-pic

Joined: 17 Sep 2003
Posts: 205

Posted: Sun Dec 24, 2006 9:11 am

acidice333 wrote:

Now I know this is for just a single, but does anybody have a modified code for multiple?

you need to use the "Search ROM" technique to find all of the devices on the onewire net; see for example,
http://www.ccsinfo.com/forum/viewtopic.php?t=21848
http://www.ccsinfo.com/forum/viewtopic.php?t=19255
etc

jds-pic

nuclear__

Joined: 24 Jan 2015
Posts: 63

can't make it work

Posted: Fri Dec 16, 2016 4:07 am

Hi there. Using 16f684 and pin_c2 with internal 8MHz osc, i try to make it work. I don't have lcd on it, it's a very simple circuit. Generally working. I have 3 leds for debugging.
Anyway i can't get temperature reading. I can see that i get no pulses to pin_c2 (with oscilloscope). When i use #use FIXED_IO( C_outputs=PIN_C2) then i do see pulses coming periodically, however it's still not reading anything but 0.
Running this at main once, i can see ledr going low:

Code:

if (onewire_init_with_error_check()) {
onewire_ds1822_set_temperature_resolution(9);
}
else {
output_low(ledr);
delay_ms(2000);
}

Probably something is wrong with my configuration.
Nothing changes if i remove ds1822.
Any tip?

Code:

#include <16F684.h>
#device ADC=8

#FUSES WDT //Watch Dog Timer
#FUSES NOPUT //No Power Up Timer
#FUSES NOMCLR //Master Clear pin used for I/O
#FUSES PROTECT //Code protected from reads
#FUSES NOCPD //No EE protection
#FUSES BROWNOUT //Reset when brownout detected
#FUSES IESO //Internal External Switch Over mode enabled
#FUSES FCMEN //Fail-safe clock monitor enabled

#use delay(internal=8000000,restart_wdt)
#use FIXED_IO( C_outputs=PIN_C5,PIN_C4,PIN_C3,PIN_C0 )

#include <ds1822.c>

#define pot PIN_A2
#define s_season PIN_A4
#define s_mode PIN_A5
#define Relay PIN_C0
#define ledR PIN_C3
#define ledG PIN_C4
#define ledB PIN_C5

nuclear__

Joined: 24 Jan 2015
Posts: 63

fixed
Posted: Fri Dec 23, 2016 3:11 pm

I removed fixed_io line and now works.

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