DS1820 display with 7-seg 4 digits

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- 20th January 2007, 16:52
chai98a

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DS1820 display with 7-seg 4 digits

Hi every one i would lioke to share with my project.
I did make temperature display and show on 7-seg.[ 45.5C ]

Code:

Define LOADER_USED 1
DEFINE OSC 4
@ Device pic16F877A, xt_OSC, BOD_OFF, PWRT_ON, WDT_OFF, PROTECT_OFF 'WRT_On

Segments Var PORTC
Digits Var PORTD

i Var Byte
n Var Byte
Value Var Word

' Allocate variables
command var byte ' Storage for command
J var byte ' Storage for loop counter
temp var word ' Storage for temperature
T VAR WORD
DQ var PORTd.4 ' Alias DS1820 data pin
DQ_DIR var TRISd.4 ' Alias DS1820 data direction pin
read_done var byte
Lastdata var word

TRISc = $00 ' Set segment pins to output
TRISd = $f0 ' Set digit pins to output
TrisB = $00
Portb = $00
portd = $ff

OPTION_REG = $50 ' Set TMR0 configuration 1:64
INTCON = $A0 ' Enable TMR0 interrupts
'On Interrupt Goto display

'ADCON1 = 7 ' Set PORTA and PORTE to digital
' Lcdout $fe, 1, "Temp in degrees C" ' Display sign-on message
'debug ====

DEFINE HSER_RCSTA 90h
DEFINE HSER_TXSTA 24h
DEFINE HSER_SPBRG 12 ' 19200 Bauds ,4 m
'debug ====

' Mainloop to read the temperature and display on LCD

mainloop:
'goto display
'Goto mainloop

Gosub init1820 ' Init the DS1820

command = $cc ' Issue Skip ROM command
Gosub write1820

command = $44 ' Start temperature conversion
Gosub write1820

'Pause 2000 ' Wait 2 seconds for conversion to complete

Gosub init1820 ' Do another init

command = $cc ' Issue Skip ROM command
Gosub write1820

command = $be ' Read the temperature
Gosub write1820
Gosub read1820

'Display the decimal temperature
'HSEROUT ["Temp = ",dec (temp>>1),".", dec (temp.0*5)," C",13,10]
'T = ((temp>> 1)*100)+((TEMP.0*5)*10)
'HSEROUT ["Temp = ",dec T ,13,10]
value = ((temp>> 1)*100)+((TEMP.0*5)*10)
GOTO DISPLAY
Goto mainloop ' Do it forever

' Initialize DS1820 and check for presence
init1820:
Low DQ ' Set the data pin low to init
Pauseus 500 ' Wait > 480us
DQ_DIR = 1 ' Release data pin (set to input for high)

Pauseus 100 ' Wait > 60us
If DQ = 1 Then
'Lcdout $fe, 1, "DS1820 not present"
PORTC = $39
LOW DIGITS.0
PAUSE 150
PORTC = $0
Pause 150
Goto mainloop ' Try again
Endif
Pauseus 400 ' Wait for end of presence pulse
Return

' Write "command" byte to the DS1820
write1820:
For i = 1 to 8 ' 8 bits to a byte
If command.0 = 0 Then
Gosub write0 ' Write a 0 bit
Else
Gosub write1 ' Write a 1 bit
Endif
command = command >> 1 ' Shift to next bit
Next i
Return

' Write a 0 bit to the DS1820
write0:
Low DQ
Pauseus 60 ' Low for > 60us for 0
DQ_DIR = 1 ' Release data pin (set to input for high)
Return

' Write a 1 bit to the DS1820
write1:
Low DQ ' Low for < 15us for 1
@ nop ' Delay 1us at 4MHz
DQ_DIR = 1 ' Release data pin (set to input for high)
Pauseus 60 ' Use up rest of time slot
Return

' Read temperature from the DS1820
read1820:
For i = 1 to 16 ' 16 bits to a word
temp = temp >> 1 ' Shift down bits
Gosub readbit ' Get the bit to the top of temp
Next i
Return

' Read a bit from the DS1820
readbit:
temp.15 = 1 ' Preset read bit to 1
Low DQ ' Start the time slot
@ nop ' Delay 1us at 4MHz
DQ_DIR = 1 ' Release data pin (set to input for high)
If DQ = 0 Then
temp.15 = 0 ' Set bit to 0
Endif
Pauseus 60 ' Wait out rest of time slot
Return
'================== 7 seg ment display ==============================
display:
'value = ((temp>> 1)*100)+((TEMP.0*5)*10)

PORTC = $39 'Show C on display
LOW DIGITS.0
PAUSEUS 1500
PORTC = $0

'value = 125
For i = 1 To 4 ' Loop through 4 digits

n = Value Dig i ' Get digit to display

' Gosub display1 ' Display the value
Digits = $ff

Lookup n, [$3F, $06, $5B, $4F, $66, $6D, $7D, $07, $7F, $6F,_
$77, $7C, $39, $5E, $79, $71, $0FF], Segments

If i = 2 then segments = segments + 128 'Digit 2 show dot

Digits = ~Dcd i

NEXT I
goto mainloop

End
- 26th January 2007, 16:02
DavidK

Centigrade/Fahrenheit

So do you have code for Fahrenheit ??
- 26th January 2007, 19:22
keithdoxey

Just convert Centigrade to Farenheit

C/5*9+32=F

although to maintain a bit more accuaracy with PBP integer maths I would do

C*9/5+32=F

then display the result followed by "F" instead of "C" :)
- 14th February 2007, 10:58
flotulopex

Why the octal buffer?

Hello chai98a,

Why did you use the 74HC541 octal buffer?

Is it because of a power issue between PIC and display?
- 14th February 2007, 18:28
sayzer

Quote:

Originally Posted by flotulopex

Hello chai98a,

Why did you use the 74HC541 octal buffer?

Is it because of a power issue between PIC and display?

I had asked the same question before.
AND I think the answer was that he had seen a design with 74HC541 somewhere. That was why.

-------------------
- 21st September 2007, 11:34
gimo

7-segment display counter

hi!!!
im new in pic programming.. please give me sample codes for a circuit that counts from 0 - 99 (2 seven segment display) when a sensor is triggered. and alarms if the sensor is not triggered or idle for about 10 seconds.. thanks!!
- 21st September 2007, 12:21
Acetronics2

Hi, Gimo

That's not sample you request, but a complete application ...

How much do you offer ???

Alain
- 22nd September 2007, 08:34
sayzer

Quote:

Originally Posted by Acetronics

Hi, Gimo

That's not sample you request, but a complete application ...

How much do you offer ???

Alain

Hey gimo,

I will accept 1 buck less then what Alain accepts. :) :)

That is, of course, IF the OFFER is > 1 buck.

:)
---------------------
- 23rd September 2007, 07:24
gimo

hahaha... just give it for free please???
- 10th April 2008, 10:58
karenhornby

How can you get the DS1820 and LCD to display actual 10ths of a degree?
My code I use for displaying the results of the conversion is

Code:

LCDOUT $FE,$C0,"Temp", $fe, $C7, dec (temp >> 1), ".", dec (temp.0 * 5), $DF, "C"

but it only seems to measure in 0.5degree steps not 0.1 degree steps
so it will never show room temperature as 19.7ºC it will instead show 19.5ºC is there a way to fix this?
Rest of the conversion code is

Code:

' Initialize DS1820 and check to see IF I was stupid enough to forget the DS1820 init1820: Low DQ ' Set the data pin low to init Pauseus 500 ' Wait > 500us DQ_DIR = 1 ' Release data pin (set to input for high) Pauseus 100 ' Wait > 100us If DQ = 1 Then Lcdout $fe, 1, "DS1820 not present" Pause 500 Goto mainloop ' Try again Endif Pauseus 400 ' Wait for end of presence pulse Return ' Write "command" byte to the DS1820 write1820: For i = 1 to 8 ' 8 bits to a byte If command.0 = 0 Then Gosub write0 ' Write a 0 bit Else Gosub write1 ' Write a 1 bit Endif command = command >> 1 ' Shift to next bit Next i Return ' Write a 0 bit to the DS1820 write0: Low DQ Pauseus 60 ' Low for > 60us for 0 DQ_DIR = 1 ' Release data pin (set to input for high) Return ' Write a 1 bit to the DS1820 write1: Low DQ ' Low for < 15us for 1 @ nop ' Delay 1us at 4MHz DQ_DIR = 1 ' Release data pin (set to input for high) Pauseus 60 ' Use up rest of time slot Return ' Read temperature from the DS1820 read1820: For i = 1 to 16 ' 16 bits to a word temp = temp >> 1 ' Shift down bits Gosub readbit ' Get the bit to the top of temp Next i Return ' Read a bit from the DS1820 readbit: temp.15 = 1 ' Preset read bit to 1 Low DQ ' Start the time slot @ nop ' Delay 1us at 4MHz DQ_DIR = 1 ' Release data pin (set to input for high) If DQ = 0 Then temp.15 = 0 ' Set bit to 0 Endif Pauseus 60 ' Wait out rest of time slot

Also:
How can you use 2 DS1820's and have them display the results on 2 different lines of the LCD, I know they are 1wire and should work fine, but how do you talk to each one individually and get the results from each one?

Quote:

Originally Posted by gimo

hi!!!
im new in pic programming.. please give me sample codes for a circuit that counts from 0 - 99 (2 seven segment display) when a sensor is triggered. and alarms if the sensor is not triggered or idle for about 10 seconds.. thanks!!

I'm a newbie just teaching myself about Pic's and programming, mainly by using snippets of other people's code and changing a few things to see what happens and try and figure out how to make it work
but the request you made can be found in numerous places, loads of sample codes contain that, and come on, its not that hard to work out, even for a wanna be blonde!
- 10th April 2008, 12:47
Acetronics2

Hi, Karen

AS the DS18x20 has a +/- .5 degrees precision ... is it useful to show the tenths of degree ???

Now, take the DS 1820 Datasheet ... How much degrees for 1 Count ???

Are you able to show the 1/10 degree ???

( Check if your DS 1820 is a DS1820 , a DS18B20, a DS 18S20 ??? )

Take the DS 18B20 Datasheet ... How much degrees for 1 Count ??? Can you read .1 degree NOW ???

NOW, for 2 DS 1820 ... Two solutions :

1) each has its DATA PIN
2) you have to address them by using their DEV i.d. before sending them commands ...

Make your choice ...

Alain
- 10th April 2008, 12:59
karenhornby

Thanks :),
but I've never programmed anything before and have only heard of stamp not used it.
I'm just teaching myself by trial and error as I go along.
hmm I can see some research coming up on how to address each device by device ID and how I find the device id to start with!
- 10th April 2008, 13:12
Acetronics2

Have a look here ...

http://www.rentron.com/PicBasic1.htm

Bottom left of the page ... just the other side you went from ...

And Thanks to Bruce !

Alain