16F872 and LCD

[Fredrick]

Hello.

Now i have connected the LCD as PBP defaults and when i run the PIC with this code the display shown the temerature for 1sec and then it shows "fffffffffffffffffffffff" on both lines for a sec and then shows the temerature again and so on...

Why?

' One-wire temperature for LAB-X1 and DS1820
define OSC 20
DEFINE LCD_COMMANDUS 2000
DEFINE LCD_DATAUS 600

temperature Var	Word			' Temperature storage
count_remain Var Byte			' Count remaining
count_per_c Var	Byte			' Count per degree C

pause 1000


DQ	Var	PORTB.2			' One-wire data pin

	ADCON1 = 7			' Set PORTA and PORTE to digital

mainloop: OWOut DQ, 1, [$CC, $44]       ' Start temperature conversion

waitloop: OWIn DQ, 4, [count_remain]	' Check for still busy converting
	
    If count_remain = 0 Then waitloop

	OWOut DQ, 1, [$CC, $BE]		' Read the temperature
    OWIn DQ, 0, [temperature.LOWBYTE, temperature.HIGHBYTE, Skip 4, count_remain, count_per_c]

	' Calculate temperature in degrees C to 2 decimal places (not valid for negative temperature)
	temperature = (((temperature >> 1) * 100) - 25) + (((count_per_c - count_remain) * 100) / count_per_c)
	Lcdout $fe, 1, DEC (temperature / 100), ".", DEC2 temperature, " C"

	' Calculate temperature in degrees F to 2 decimal places (not valid for negative temperature)
	temperature = (temperature */ 461) + 3200
	Lcdout $fe, $c0, DEC (temperature / 100), ".", DEC2 temperature, " F"

    Pause 1000                      ' Display about once a second

	Goto mainloop			' Do it forever

[Acetronics2]

Hi,

Try this for Waitloop ...

'*****************************************************************************
' Check for still busy converting ( ~ 4500 fois ... )
'*****************************************************************************

waitloop: 

		INPUT DQ
		If NOT DQ Then waitloop

AND ....

DEFINE LCD_DATAUS 600

Should be ...

DEFINE LCD_DATAUS 60

Alain

[Fredrick]

Doesn´t work.

[Acetronics2]

Aha ...

' One-wire temperature for Picboard and DS1820

'Ok le 29/08/2004 - 534 lignes


' Define LCD registers and bits

Define	LCD_EBIT	1

DQ				Var	PORTB.4		' One-wire data pin
Ok				Var PORTB.5		' Led Verte
Waito			Var PORTB.6		' Led Orange
Error			Var PORTB.7		' Led Rouge


temperature 	Var	Word			' Temperature storage
count_remain 	Var Byte			' Count remaining
count_per_c 	Var	Byte			' Count per degree C
offset			Var Word			' 100 * offset réel !!!

offset = 293

PAUSE 500
LCDOUT $FE,1


'*****************************************************************************
' Start temperature conversion
'*****************************************************************************

mainloop: OWOut DQ, 1, [$CC, $44 ]

'*****************************************************************************
' Check for still busy converting ( ~ 4500 fois ... )
'*****************************************************************************

waitloop: 

		INPUT DQ
		If NOT DQ Then waitloop
	
'*****************************************************************************
' Read the temperature
'*****************************************************************************
	
	OWOut DQ, 1, [$CC, $BE ]		
	
    OWIn DQ, 0, [temperature.LOWBYTE, temperature.HIGHBYTE, Skip 4, count_remain, count_per_c]

'*****************************************************************************
' Calculate temperature in degrees C to 2 decimal places (not valid for negative temperature)
'*****************************************************************************
	
	temperature = (((temperature >> 1) * 100) - 25) + (((count_per_c - count_remain) * 100) / count_per_c)+ offset
	
	Lcdout $fe, 1, DEC (temperature / 100), ".", DEC2 temperature, " ",$DF,"C" 
	
'*****************************************************************************
' Calculate temperature in degrees F to 2 decimal places (not valid for negative temperature)
'*****************************************************************************
	
	temperature = (temperature */ 461) + 3200
	Lcdout $fe, $c0, DEC (temperature / 100), ".", DEC2 temperature, " ",$DF,"F"
	
'*****************************************************************************
' Display about once a second
'*****************************************************************************

        Pause 1000                      

	Goto mainloop			' Do it forever

looks we have the same source !!! ... This one works perfectly aboard a 16F84 ...

soo ... let's check the 872 config ... AND,AND,AND :


Wich PbP version do you use ... and has your PBPpic14.lib being modified ???

There was an interesting thread those days about 1Wire and > 8 Mhz Osc ...

see here : http://www.picbasic.co.uk/forum/show...79&postcount=4

Alain

[Fredrick]

I use PBP v2.45 and have not modified anything.

The PIC runs on OSC 20


Edit: Just tryed to put in a 4 Mhz crystal but i does´t work

[skimask]

I use PBP v2.45 and have not modified anything.
The PIC runs on OSC 20
Edit: Just tryed to put in a 4 Mhz crystal but i does´t work

Apparently, the bug mentioned at the end of post #9 is only applicable to PBP2.50(a).

But still, something wierd going on...

Change your LCD_DATAUS from 600 to 255.
LCD_DATAUS is a byte value (up until PBP2.50 as far as I know), so 600 is actually 88 (600 - 256 - 256 ) as far as PBP knows.

Past that...
Check the pullup on MCLR?
Watchdog timer off?

[Fredrick]

I dont know what i have done but now the display shows "333333333333333" on both lines and some times the temerature shows on diffrent positions in the display whit "3" all over the display.

The display is an HD44780 OLED, can the display be broken?

The PBP Hello World sampel works..

[Bruce]

Place this in the first section of your code;

@ device pic16F872, hs_osc, wdt_off, pwrt_on, lvp_off, protect_off

Change DEFINE LCD_DATAUS 600 to DEFINE LCD_DATAUS 50.

Does it work now?

[skimask]

I use PBP v2.45 and have not modified anything.

Sounds like it's time to get the 2.50a update...

[Fredrick]

Why? 2.45 should work...

And update the PBP is not an garanti for that i will work..