16F872 and LCD

[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..

[skimask]

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..

I'm sure the 'Hello World' sample works just fine, but when you start messing around with some of the special LCD commands and stuff, the LCD timing starts to matter.
Did you change the LCD_DATAUS yet?

[Fredrick]

Yes i have.

[skimask]

Give this a shot:

@ DEVICE PIC16F872, HS_OSC, WDT_OFF, PWRT_ON, LVP_OFF, PROTECT_OFF
DEFINE OSC 20
DEFINE LCD_COMMANDUS 3000
DEFINE LCD_DATAUS 250
temperature var word : count_remain var byte : count_per_c var byte
dq var portb.2 : ADCON1 = 7 : pause 1000 : lcdout $fe , 1
mainloop: OWOut DQ , 1 , [ $CC , $44 ]
waitloop: OWIn DQ, 4, [count_remain]	 : If count_remain = 0 Then waitloop
owout dq, 1, [$cc,$be]
owin dq , 0 , [ temperature.lowbyte , temperature.highbyte , skip 4 , count_remain , count_per_c ]
temperature = ( ( ( temperature >> 1 ) * 100 ) - 25 ) + ( ( ( count_per_c - count_remain ) * 100 ) / count_per_c )
Lcdout $fe , $80 , DEC3 ( temperature / 100 ) , "." , DEC2 temperature, " C"
temperature = ( temperature * / 461 ) + 3200
Lcdout $fe , $c0 , DEC3 ( temperature / 100 ) , "." , DEC2 temperature , " F"
Pause 1000 : goto mainloop

Also, in your original code, you show:
define OSC 20

Put all DEFINE's in upper case. It's a bit weird like that.
Your original code was probably still compiled as if it were for a 4 Mhz oscillator, even though you had 'define OSC 20'.

[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?

[Fredrick]

No i does not work...

[Fredrick]

temperature = ( temperature * / 461 ) + 3200

ERROR Line 23: Bad expression. (TEST.pbp)


I use Microcode Studio and microcode put define in uppercase by auto, or do i still have to write it in uppercase?

[skimask]

temperature = ( temperature * / 461 ) + 3200

ERROR Line 23: Bad expression. (TEST.pbp)


I use Microcode Studio and microcode put define in uppercase by auto, or do i still have to write it in uppercase?

I just write it in uppercase myself.
No questions about it then.
As far as the bad expression, the fix is in the manual.

[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..

[skimask]

Why? 2.45 should work...

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

The update is only $25, get a new book, all the fixes, support for 32 bit variables, etc.

[Fredrick]

Maybe i will do that, but still i want to get the LCD to work now..... with the current version...

[skimask]

Maybe i will do that, but still i want to get the LCD to work now..... with the current version...

Are you using the PBP DEMO version?