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linux123
Joined: 09 Oct 2006
Posts: 17
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| two DS18s20 (indoor and outdoor) |
 Posted: Mon Oct 16, 2006 4:58 pm |
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Hy, i need check two temps, indoor and outdoor, i use DS1820, from Dallas, the protocol is 1-wire, whats read two sensor ?
My MCU is 18F452.
Thanks. |
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LazBoy
Joined: 17 Oct 2006
Posts: 8
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| Posted: Tue Oct 17, 2006 5:35 am |
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This is my solution. I know, not a optimal solution but it works.
I modified this code from http://www.vermontficks.org/pic.htm (Jon Fick)
This is working code but a litlle slow communication:
You may decide seperate 2 pin for Indoor and Outdoor sensors.
Include this two sensor files to your project:
Variables:
| Code: |
#define DS1820_SKIP_ROM 0xCC
#define DS1820_READ_SCRATCHPAD 0xBE
#define DS1820_CONVERT_T 0x44
#define INDOOR_PIN PIN_A0
#define OUTDOOR_PIN PIN_A1
static char cShiftBit,cDataOut;
static long iTemperature,iDataIn;
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indoor.c
| Code: |
///////////// INDOOR ///////////////////////
void ResetDS1820_Indoor( void )
{
output_low ( INDOOR_PIN );
delay_us ( 480 );
output_float ( INDOOR_PIN );
delay_us ( 480 );
}
void WriteDS1820_Indoor ( void )
{
for ( cShiftBit = 1; cShiftBit <= 8; ++cShiftBit )
{
output_low ( INDOOR_PIN );
delay_us ( 5 );
output_bit ( INDOOR_PIN, shift_right ( &cDataOut, 1, 0 ) );
delay_us ( 60 );
output_float ( INDOOR_PIN );
delay_us ( 5 );
}
}
void ReadDS1820_Indoor ( void )
{
iDataIn = 0;
for ( cShiftBit = 1; cShiftBit <= 16; ++cShiftBit )
{
output_low ( INDOOR_PIN );
delay_us ( 5 );
output_float ( INDOOR_PIN );
delay_us ( 5 );
shift_right ( &iDataIn, 2, input ( INDOOR_PIN ) );
delay_us ( 55 );
}
}
void WaitForConversion_Indoor ( void )
{
while ( TRUE )
{
output_low ( INDOOR_PIN );
delay_us ( 5 );
output_float ( INDOOR_PIN );
delay_us ( 5 );
if ( input ( INDOOR_PIN ) == 1 )
{
break;
}
delay_us ( 55 );
}
}
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outdoor.c
| Code: |
///////////// OUTDOOR ///////////////////////
void ResetDS1820_Outdoor( void )
{
output_low ( OUTDOOR_PIN );
delay_us ( 480 );
output_float ( OUTDOOR_PIN );
delay_us ( 480 );
}
void WriteDS1820_Outdoor ( void )
{
for ( cShiftBit = 1; cShiftBit <= 8; ++cShiftBit )
{
output_low ( OUTDOOR_PIN );
delay_us ( 5 );
output_bit ( OUTDOOR_PIN, shift_right ( &cDataOut, 1, 0 ) );
delay_us ( 60 );
output_float ( OUTDOOR_PIN );
delay_us ( 5 );
}
}
void ReadDS1820_Outdoor ( void )
{
iDataIn = 0;
for ( cShiftBit = 1; cShiftBit <= 16; ++cShiftBit )
{
output_low ( OUTDOOR_PIN );
delay_us ( 5 );
output_float ( OUTDOOR_PIN );
delay_us ( 5 );
shift_right ( &iDataIn, 2, input ( OUTDOOR_PIN ) );
delay_us ( 55 );
}
}
void WaitForConversion_Outdoor ( void )
{
while ( TRUE )
{
output_low ( OUTDOOR_PIN );
delay_us ( 5 );
output_float ( OUTDOOR_PIN );
delay_us ( 5 );
if ( input ( OUTDOOR_PIN ) == 1 )
{
break;
}
delay_us ( 55 );
}
}
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| Code: |
ResetDS1820_Indoor();
cDataOut = DS1820_SKIP_ROM;
WriteDS1820_Indoor();
cDataOut = DS1820_CONVERT_T;
WriteDS1820_Indoor();
WaitForConversion_Indoor();
ResetDS1820_Indoor();
cDataOut = DS1820_SKIP_ROM;
WriteDS1820_Indoor();
cDataOut = DS1820_READ_SCRATCHPAD;
WriteDS1820_Indoor();
ReadDS1820_Indoor();
iTemperature = iDataIn / 2; // INDOOR Temperature
// LCD or 7Seg Call routines here
ResetDS1820_Outdoor();
cDataOut = DS1820_SKIP_ROM;
WriteDS1820_Outdoor();
cDataOut = DS1820_CONVERT_T;
WriteDS1820_Outdoor();
WaitForConversion_Indoor();
ResetDS1820_Outdoor();
cDataOut = DS1820_SKIP_ROM;
WriteDS1820_Outdoor();
cDataOut = DS1820_READ_SCRATCHPAD;
WriteDS1820_Outdoor();
ReadDS1820_Outdoor();
iTemperature = iDataIn / 2; // OUTDOOR Temperature
// LCD or 7Seg Call routines here
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Bytheway,
I am not good with C. How can we use only one routine for both 2 sensors for code space optimization ?
Any suggestions wellcome.
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Last edited by LazBoy on Thu Oct 19, 2006 1:21 pm; edited 1 time in total |
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linux123
Joined: 09 Oct 2006
Posts: 17
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| Stop |
| Posted: Wed Oct 18, 2006 4:46 pm |
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Hy, the code stop begin call function, read temp_indoor, but, my code continue load, because call interrupt from serail RX, response, and i add call from SKIP ROM.
Thanks. |
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linux123
Joined: 09 Oct 2006
Posts: 17
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| Ok. |
| Posted: Thu Oct 19, 2006 7:04 am |
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The code it's ok, but, have insert:
#define DS1820_SKIP_ROM 0xCC
#define DS1820_READ_SCRATCHPAD 0xBE
#define DS1820_CONVERT_T 0x44
I go job to add precision, because, the code return decimal value.
If anybody help-me, i thanks. |
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LazBoy
Joined: 17 Oct 2006
Posts: 8
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| Posted: Fri Oct 20, 2006 6:09 am |
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I added missed variables.
Yes, it hangs If there is no sensor on communication pin.
You may fix it for your needs.
| Code: |
void ResetDS1820_Indoor( void )
{
INDOOR_SENSOR_NOT_FOUND = FALSE;
output_low ( INDOOR_PIN );
delay_us ( 480 );
output_float ( INDOOR_PIN );
delay_us ( 20 );
if ( input ( INDOOR_PIN ) == 1 )
{
INDOOR_SENSOR_NOT_FOUND = TRUE;
Break;
}
delay_us ( 460 );
}
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