Slow starting up

[lerameur]

hello,

Not sure when I should put this...
I have a program working 100% on the breadboard.
I made a prototype board (soldering) , use the same chip and put in the socket of the prototype board. guess what.. its takes about 8 to 40 seconds to get running and showing values on the LCD..
..sometimes it will show only half the LCD screen for a couple of seconds then will show all what is suppose to show.
First, it should take just 1 second to show the info on the LCD
Second, like I said its the same chip.. put it back on the breadboard and it works.... Same value 10k MCLR,

Anybody had this issue before ???
I 'd rather it not be working instead of this...

K

[lerameur]

I will post the code, because I think that might be issue here... I used another PIC from a previous project and its working ..

INCLUDE "modedefs.bas" 'Includes supoprt for PicBasic language

OSCCON = %01100000 '4 Mhz
DEFINE OSC 4
  
CMCON = 7 : ADCON1 = 7
DEFINE LCD_DREG PORTB ' Set LCD Data port
DEFINE LCD_DBIT 4 ' Set starting Data bit (0 or 4) if 4-bit bus
DEFINE LCD_RSREG PORTA ' Set LCD Register Select port
DEFINE LCD_RSBIT 2 ' Set LCD Register Select bit
DEFINE LCD_EREG PORTA ' Set LCD Enable port
DEFINE LCD_EBIT 3 ' Set LCD Enable bit
DEFINE LCD_BITS 4 ' Set LCD bus size (4 or 8 bits)
DEFINE LCD_LINES 2 ' Set number of lines on LCD
DEFINE LCD_COMMANDUS 2500
DEFINE LCD_DATAUS 250
DEFINE CHAR_PACING 2000
pause 1500


' Define ADCIN parameters
Define ADC_BITS 10 ' Set number of bits in result
Define ADC_CLOCK 3 ' Set clock source (3=rc)
Define ADC_SAMPLEUS 50 ' Set sampling time in uS

DEFINE CCP1_REG PORTB 
DEFINE CCP1_BIT 0 
ANSEL = %00000010 ' set   AN1  as analog, others to digital

ADCON1 = %10000010 ' Set PORTA analog for ten bit ADC
'ADCON0 = %00000001 ' Configure and turn on A/D Module

TRISB = %01000010
TRISA = %00000111

DutyCycle var word
Frequency  var word

Mainloop:

ADCON0.2 = 1			'Start Conversion
pause 20	
ADCIN 0, DutyCycle 'Read channel PORTA.0 Duty Cycle
ADCIN 1, Frequency 'Read channel PORTA.1 Frequency
 Frequency = Frequency + 245
 DutyCycle = DutyCycle/4
 
lcdout $FE,1, "DutyCycle: ", dec DutyCycle
lcdout $FE,$C0, "Frequency: ", dec Frequency
pause 100

HPWM 1,DutyCycle,Frequency 'channel, dutycycle, frequency
pause 20

goto Mainloop

END

[Archangel]

Solder-less breadboards have a ton of capacitance, between traces, probably need some on the crystal to get reliable OSC start . . . also add caps to LCD power pins. If you're using a resonator use HS not XT in your configs?

[lerameur]

I have a 1uF cap, and using 4mhz internal clocking.

[Acetronics2]

may preset the outputs levels ...

and explicitly write the chip config ...

[lerameur]

I have an earlier version of that program, ( and no I changed it since) and that version work, meaning does not have this problem.
I guess something is wrong with the code..

K

[Archangel]

Hi Ken,
Let's have a look at your config statements please . . . Are you using internal osc on the breadboard too?
Sometimes if PICs power up too slowly they flounder a bit before starting, also backfeeds make for strange behavior. . .

[AvionicsMaster1]

According to the PBP3 manual LCDOUT command: "A program should wait for up to half a second before sending the first command to
an LCD. It can take quite a while for an LCD to start up". I don't see the wait time in your code.

Is it possible to have full code, schematic and some part numbers of major components?

[wdmagic]

I had a issue with time using a 16F877 chip the first time, I tried setting it to internal OSC in the fuse section of my programmer software, Apparently i did something wrong because it took about 1 minute for my lcd to come on, and even though my longest pause was 1 second, the fastest updates on my lcd were about 30 seconds, talk about problems with adc and such, I gave up on it at the time and havent used a 877 since. Im sure its something simple, if your using a external crystal make sure its got good connections to board, if its shorted or open perhaps the chip is changing to internal osc to prevent damage? not sure logically as long as your board is wired identical to the breadboard connections there is no logical reason it should not fuction the same... with the exception of capacitance, resistance, and inductance inherant in using jumper wires and mechanical connections. this is not usually a problem on breadboards. likely your problem would be in reverse, it works on PCB but not on breadboard if that was the issue.
Perhaps, based on what you have other than your PIC, perhaps leave the PIC off the PCB and check continuity on buttons, diodes, etc.

and dont forget to take a break or work on some other PIC project for a bit. Sometimes I get into bulldozer mode when I have a problem, 12 hours later im fruserated and tired and its still not working... but a break or playing with some other code makes me relax a bit and sometimes the fix just comes when your not trying so hard.

when I design PCB's it helps sometimes to print it out and the schematic and compare and mark off parts and connections, see if your missing something or have something in the wrong location.

Hope you figure it out.