F886 & pgm

[MOUNTAIN747]

I am working with the 16F886 for the first time. My compiler is PBP 2.60. After an hour trying to get the blinky light program to work (never had this problem on any other PIC) I looked for Post’s that may give me a hint as to what I may be doing wrong. I came across a Post on the 16F819 (another internal clock) that said it would not work unless PGM was tied low. I’ve never had this problem with an F819 but it solved the problem on my 886. If I remove the PGM low the PIC stops operating. I tried several 16F866 and all were the same results. This means I loose RB3 as an I/O. I haven’t tried using external oscillator on the F886 because I would like to use all I/O’s on this project. I’ve never seen any comments about this 886 charictoristec on any Post. Is there something I can do to eliminate the need for the PGM to ground?

@ DEVICE INTRC_OSC_NOCLKOUT,MCLR_OFF,BOD_OFF,WDT_OFF

comments will be appreciated!

[Bruce]

Add LVP_OFF to your config settings.

[MOUNTAIN747]

Thanks for your reply Bruce.
No dice! I thought that would do it also. Once I pull the ground wire off RB3 the LED continues to blink for about five seconds then stops.

There is also another strange thing going on. PORTA.6&7 when in digital output state drivers only 2.4V unloaded then drops to 1.3 & 1.9 respectfully under LED load. I’ve turned off everything I can think of that deals with OCS1&2.

@ DEVICE INTRC_OSC_NOCLKOUT,MCLR_OFF,BOD_OFF,WDT_OFF,LVP_OFF  
OSCCON=$70
ANSEL=$00
ADCON0=$00

[mackrackit]

This is for MPASM..

@ __config _CONFIG1, _INTRC_OSC_NOCLKOUT & _WDT_ON & _MCLRE_OFF & _LVP_OFF & _CP_OFF

Notice the E on MCLR E

[Bruce]

If only RB3 causes your problem, then I suspect you're simply not getting LVP turned off.

It would really help if you posted your code.

[Archangel]

You got analog all to heck on port B, shut off the comparators and don't forget anselh

[MOUNTAIN747]

So here’s the scoop! I’ve tested this on multiple F886 and on multiple programmers with PBP2.60 and PBP2.46.

Bruce your right!

“If only RB3 causes your problem, then I suspect you're simply not getting LVP turned off.”

PBP 2.60/melabs programmer 4.23

@ DEVICE INTRC_OSC_CLKOUT,MCLR_OFF,BOD_OFF,WDT_OFF,LVP_OFF  
OSCCON=$70
ANSEL=     $00
ADCON0=   $00
CM1CON0 =$00 
CM2CON0 =$00

Program, Read Code, View – Configuration
Low Voltage Programming --- Enabled
Must tie RB3 to Vss ... Remove Vss on RB3 MCU stops after about 5sec.
Digital output voltage on RA7 low

PBP 2.46/melbas programmer 4.23
Same code
Program, Read Code, View – Configuration
Low Voltage Programming --- Disabled
No Vss needed on RB3 ... Digital output voltage on RA7 correct

Hobbyist was near wits end! Now What?

[ScaleRobotics]

don't forget anselh

I don't see anselh in your settings...

[Bruce]

Hmm. That is an interesting problem.

Try this. Save the file you're compiling in your 2.60 directory with one name, and save
a 2nd copy of the same file in your 2.46 directory with a different name.

Compile the one with 2.60. Open it with your MeLabs programmer software, and click on
the C radio button. You should see a screen with config settings like the one I have
attached.

Now open the file in your 2.46 directory, and repeat. Are config settings the same?

[MOUNTAIN747]

I’ve tried ANSELH=$00 with the same results. In fact BOR was also Enabled along with a few other items. It did set internal osc at 8Mhz with clockout at 2Mhz.

I used the code file on different computers. One with 2.60 and the other with 2.46. And yes I clicked the C radio button to take a look at the Configs.

I think I’ll try reloading 2.60 on the computer to see if there are any changes in results.

[Bruce]

If you're doing this on two different PCs, it may be that you just have different settings for the MeLabs programmer. Make sure you have Options >> Update Configuration From File checked on the 2.60 machine. That sounds like the problem.

You previously programmed it with LVP_ON, and it's not updating config settings.

[MOUNTAIN747]

Bruce,
I've checked both computers. Both computers were set to "Update Configuration from file". 2.46 Config default option was set to LVP_off. 2.60 was set to LVP_on. I changed that setting and recompiled with the same results, LVP is NOT turning off on 2.60.

[MOUNTAIN747]

I got it. I was not saving the new default setting on 2.60. There is still the issue of why the file was not recognized when default setting on the programer was set to "Update Configuration from file". However 2.60 is now turning off LVP as it should, but only because the default LVP was changed.

I learned a lot about PBP defaults and LVP. I also was unaware that I could have a digital out put with an analog input (ANSELH), at least that what I got out of reading the datasheet on ANSELH.
Thank you all for your assistance.

[Bruce]

Here's a really quick/easy way to find out if it's the compiler or a different setting in your
programmer software.

Compile it on your 2.60 machine. Transfer the .HEX file to your 2.46 machine.

Open the .HEX file & program & test the PIC.

[MOUNTAIN747]

Thanks Bruce, I'll give it a try.