Problem with 16Ff648a

[Acetronics2]

HI

Just cut and paste ...

replace LOOP for LOOP1 for PBP 2.60

...

Success 84 Words used

So, this is not a chip problem ( I often use both chips ... no difference @ use )

BINGO ...
You should verify your Arrays declarations ... " illegal syntax " ...

Alain

[aerostar]

I knew about the LOOP variable and had changed its name for 2.60, and the result is the same, yes 84 words used, but it crashes, compiled with 2.43 or 2.6.

The configuration bits are the same for 628A and 648A, the only difference in these 2 chips is the extra memory size.

CLEAR is definately the problem, as if it is removed the program works, put it back and it does not. As far as I know CLEAR only writes zeros into all the declared memory locations and does nothing else


Perhaps someone at Melabs could give me the reason why removing CLEAR makes the program work.

[mackrackit]

Stupid question...
But are you changing this line as needed?
@ device PIC16F648A,HS_OSC,BOD_ON,MCLR_ON

And selecting the correct PIC at compile time?

[aerostar]

Stupid question...
But are you changing this line as needed?
@ device PIC16F648A,HS_OSC,BOD_ON,MCLR_ON

And selecting the correct PIC at compile time?

Yes.
PIC data sheet DS40044F, Page 1 says

pic 628a program words 2048, sram 224 bytes, eeprom 128 bytes,

pic 648a program words 4096, sram 256 bytes, eeprom 256 bytes,


As I said the ONLY difference between the 628A and 648A is the extra memory size, program, and EEprom, you can, as I have proved, put the hex file of the 628A into the 648A and it works. The compiled size for 628A is 77 bytes with PB2.43. Compile for the 648A and size is 84 words. ( extra words presumably to account for the bit extra memory)

I have now reduced the program to its simplest form for 648A, and before anyone else raises the configuration bits on programming, they are standard, HS,watchdog, power up timer, brownout, master clear reset are all selected, code protection off,and the correct pic.

*************PROGRAM 1 compiles to 51 words pb2.43 and pb2.6
DEFINE OSC 20
CHECKVARIABLE VAR BYTE

TEST:
LOW PORTB.7
PAUSE 250
HIGH PORTB.7
PAUSE 250
GOTO TEST

the above WORKS !

*********PROGRAM 2 with the CLEAR ADDED compiles to 73 words pb2.43 and pb2.6

DEFINE OSC 20
CHECKVARIABLE VAR BYTE
CLEAR
TEST:
LOW PORTB.7
PAUSE 250
HIGH PORTB.7
PAUSE 250
GOTO TEST

The above does NOT WORK.

you can even remove my CHECKVARIABLE and the results are the same.
eg
DEFINE OSC 20
CLEAR
TEST:
LOW PORTB.7
PAUSE 250
HIGH PORTB.7
PAUSE 250
GOTO TEST
does not work

So it still looks as though the CLEAR is causing the problem, CLEAR only writes zeros to all the ram memory space, so it does not matter whether you have variables declared or not.

[Acetronics2]

Hi,

At the moment ...

I have my personnal 18 pins test board in front of me, Pic is a 16F648a, loaded with your program ( no mod ... )

you know what ??? ...

Led @ PortB.7 BLINKS !!!

Picture required ???

soooo ... try another '648 ... after checking your board and solders ...

Alain

[Acetronics2]

A '628 programmed with the '648 Hex file also works fine ...

Alain

[aerostar]

Hi,

At the moment ...

I have my personnal 18 pins test board in front of me, Pic is a 16F648a, loaded with your program ( no mod ... )

you know what ??? ...

Led @ PortB.7 BLINKS !!!

Picture required ???

soooo ... try another '648 ... after checking your board and solders ...

Alain

Hi Alain, thanks for the info, can you just confirm that you tried the 648A with the CLEAR.

The PCB is a commercially made board, currently in use, and just has the pic changed. I have tested 2 PCBs known working, with same result.

If yours does work, then I think there can only be 2 suspects left.

Suspect 1
The pics, I have tried 3 brand new ones, and all show the same problem, I have more but they are all the same batch, I will have to see if I can get a different batch.


Suspect 2
The programmer is not programming correctly, I use the Melabs EPIC programmer connected to LPT2, correct PSU and correct programming volts (re-checked this morning).

The EPIC programmer software is 2.46beta, latest for this from Melabs site. I have tried the Melabs programmer 4.32beta, but that does not work, it does not read the chip ID.

I will have to take the hex file to a friend tomorrow and get him to program the pic, at least that would rule out the programmer one way or another.

OH...... yes there is a final suspect.......................Me !!

Thanks all for your help.

[Acetronics2]

Hi,

Yes, was with the CLEAR command enabled ( I verified it was also in the Asm listing ...)

but, I begin to think your programmer doesn't set the config word correctly ... ( most common reason for such behaviour ... )

could you read back the config word of one of your PICs w/ the programmer ???



Alain

[Darrel Taylor]

... The EPIC programmer software is 2.46beta, latest for this from Melabs site.

That's the latest for epicwin, but it's not the latest for the epic programmer.

Try using meProg, which works with all the programmers ... epic, serial, U2 and Field programmers.
http://www.melabs.com/support/progsoft.htm
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[aerostar]

Thanks Darrel, but I did say in my post at 15:51

The EPIC programmer software is 2.46beta, latest for this from Melabs site. I have tried the Melabs programmer 4.32beta, but that does not work, it does not read the chip ID.

and will not even program the chip with the ID detect turned off.

More info when I do some more testing....