Can't get a 16F88 to do anything.

[ccowley]

Is there anyone out there willing to give me a code sample that will flash an LED using a 16F88 (code from start to finish including all fuse settings etc.).

I have worked with lots of PIC's, though mostly the 12F series lately. I started out programming microcontrollers in HEX, then graduated to assembly, and have been using PICBasic PRO for years (currently using v 2.47). I am very familair with them and usually don't have any problems, but this 16F88 is kicking my tail! I have the CMCON, ANSEL, TRIS settings, & OSCCON to what I'm pretty sure are the correct settings (though I have tried a few different settings), but still nothing.

I have looked over all the similar links and have tried everthing in them and I still can't get a blinking LED from this chip. I always start with a new chip by getting an LED blinking, but I just can't seem to get it. I have spent hours on this! It's got to be some little thing I am missing, but I haven't been able to see it. At this point I am just throwing any piece of code in there.

So, all I need is some known good code. I don't care which port you put it on or anything, just give me a blinking LED that usies the internal RC oscillator at 8MHz, no comparators turned on, no analog, just digital I/O all all the ports.

I have tried different chips (3) and different breadboards and different power supply's.

I am using Microcode Studio Plus as my editor, I then import the file the MPLab like I do with all my other chips. I have set the chip selection to correct one in both Mircode Studio Plus and MPLab. I have tried setting the fuses through the code (which is what I usually do) and manually, neither way has worked for me. My code doesn't spit out any errors (not that it means too much).

I am stuck! Any help would be greatly appreciated.

Carl

[mackrackit]

Welcome,
Generally we like to have the problem code posted, then we can help you find the problem.
http://www.picbasic.co.uk/forum/showthread.php?t=1742

Post #20 in this thread has blinky code
http://www.picbasic.co.uk/forum/show...ighlight=16F88

[Archangel]

Hi ccowley,
Welcome to The Forum, let's pretend, just for hoots, that you are a complete newbie, and we are the starving code hungry dogs,<b> I did say we are pretending didn't I ?</b> Throw us some bones of your startup code, maybe a little meat on those bones (a loop or 2 ), a little copy paste of what you have tried . . . and we'll see if you did something wrong, just so you don't have to edit the hex later

[ccowley]

Hi again,

Thanks to both of you for your input! I really appreciate the response, but things still aren't working. I did read through the entire thread that was linked to (among others) and tried everything that was suggested. The code snippit below is the from that thread and is the one I have been working with today. I have spent another 4 hours playing with this thing and it just isn't going.

I have repeated the results with two different bread boards and two different power supplys and I have rotated through 4 diffent chips and get the same results. I have checked my power and ground connection also. I can't remember ever have this kind of trouble with a microcontroller (well, okay, there were a few hairy times back in wirewrap days in college with a certain 6502 chip).

So, here is the code that I am using:

OSCCON = %01101110 'set int osc to 4mhz
'OSCON = %01100000
ANSEL = 0 'ALL DIGITAL
CMCON = 7 'COMPARATORS OFF

TRISA = %00000000 'ALL OUTPUTS
TRISB = %00000000 'ALL OUTPUTS
PORTA = 0 'PORTA LOW

@ DEVICE MCLR_OFF, INTRC_OSC, WDT_ON, LVP_OFF, BOD_OFF, PWRT_ON, PROTECT_OFF
Pause 100 'SETTLE DOWN

START:
High PORTA.6 'ON LED
High PORTA.7
Pause 1000
Low PORTA.6 'OFF LED
Low PORTA.7
Pause 1000
GoTo START 'REPEAT FOREVER

end

I have also tried it with the edited INC file and unedited INC file as mentioned in the other thread, but it doesn't change anything.

One odd note is that RB5 is always a constant 5V on every chip that I have tried so far (up to 4 now). I checked it with a scope to see if it was a clock signal or something, but it is a solid 5v.

Thanks in advance!

Carl

[mikendee]

Hi Carl,
I usually use
OSCCON = %01101000 and it seems to work. Don't forget the Define OSC for speeds other than 4MHz.
Hope this helps.
Mike

[ccowley]

Hi Mike,

Thanks for taking a look at it. I tried the OSCCON value that you suggested and it still didn't work. I am beginning to wonder if it must be a compiler error, but I'm sure I'm not the only one using these that is still on PBP 2.47. I ordered upgrade to PBP 2.50 today just in case, but I'm not conviced that's the answer.

Thanks again,

Carl