Problem with 16Ff648a

[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

[aerostar]

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

The 648A works without the CLEAR and the config is correct when read back.

Also as earlier if I put the 628A hex file which has the CLEAR into the 648A pic it works, but not when compiled for 648A.

Tomorrow I will change the program so that it does a certain amount of loops to toggle the rb7 then put the clear and repeat the code and see if it stops after the clear, that way it would confirm that it is or is not something to do with the clear.

eg

toggle the port 20times*** if this works, programmer must be OK and pic
clear
toggle the port 20 times **** if it stops here then !!!!!!!
repeat sequence

[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
<br>

[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....

[aerostar]

Early morning test .........


After thinking about it overnight I wondered if the pic was not crashing but re-starting, so I put the following into the the pic, the porta loop lets me know that the program has started, and will let me know if the pic restarts.

With the CLEAR in between the portb loops it never executes the 2nd, but restarts the program ! as port A.0 starts toggling again.

Remove the CLEAR and it works as expected, so I will have to get a different batch of 648As to see if it is the pics.





DEFINE OSC 20

COUNTER VAR BYTE
FOR COUNTER = 0 TO 10 ' confirms beginning of program

LOW PORTA.0
PAUSE 250
HIGH PORTA.0
PAUSE 250
NEXT


TEST:

FOR COUNTER = 0 TO 20

LOW PORTB.7
PAUSE 250
HIGH PORTB.7
PAUSE 250
NEXT

CLEAR

FOR COUNTER = 0 TO 20

LOW PORTB.7
PAUSE 500
HIGH PORTB.7
PAUSE 500
NEXT

GOTO TEST

[Darrel Taylor]

Thanks Darrel, but I did say in my post at 15:51 ... I have tried the Melabs programmer 4.32beta

Woops. My bad.
As soon as I see 2.46 beta, I stop looking for anything else.

I would be curious what happens with this program.
Since about the only difference between the 628A and 648A programs will be clearing the additional RAM in BANK2.

This program tries to clear the same memory without the clear statement.
It doesn't do banks 0 or 1 because they were already checked with the 628 program loaded in the 648.

DEFINE OSC 20 

Idx     VAR BYTE
B2RAM   VAR BYTE[80] BANK2
COUNTER VAR BYTE

FOR COUNTER = 0 TO 10 ' confirms beginning of program
    LOW PORTA.0
    PAUSE 250
    HIGH PORTA.0
    PAUSE 250
NEXT

TEST:

FOR Idx = 0 TO 79
    B2RAM(Idx) = 0
NEXT Idx

LOW PORTA.0   ' turn LED on to indicated completed
              ' may need HIGH don't know which way the LED is.
STOP

Probably nonsense, but I'm still curious.
<br>

[aerostar]

This program tries to clear the same memory without the clear statement.
It doesn't do banks 0 or 1 because they were already checked with the 628 program loaded in the 648.

DEFINE OSC 20 

Idx     VAR BYTE
B2RAM   VAR BYTE[80] BANK2
COUNTER VAR BYTE

FOR COUNTER = 0 TO 10 ' confirms beginning of program
    LOW PORTA.0
    PAUSE 250
    HIGH PORTA.0
    PAUSE 250
NEXT

TEST:

FOR Idx = 0 TO 79
    B2RAM(Idx) = 0
NEXT Idx

LOW PORTA.0   ' turn LED on to indicated completed
              ' may need HIGH don't know which way the LED is.
STOP

Probably nonsense, but I'm still curious.
<br>

Hi Darrel

Thank you very much for the code, it works with no problem, I then modified it to check that after writing 0 to the location it was read back to see if it had been written correctly, answer is yes. I then made it keep doing, and again no failures.

Something is very strange. I have ordered some more 648As from another supplier, they may arrive tomorrow


I have just been looking through the listing and see that PB shows the following

16 =0020 RAM_START EQU 00020h
17 =01EF RAM_END EQU 001EFh
18 =0003 RAM_BANKS EQU 00003h
19 =0020 BANK0_START EQU 00020h
20 =007F BANK0_END EQU 0007Fh
21 =00A0 BANK1_START EQU 000A0h
22 =00EF BANK1_END EQU 000EFh
23 =0120 BANK2_START EQU 00120h
24 =01EF BANK2_END EQU 001EFh
25 =2100 EEPROM_START EQU 02100h
26 =21FF EEPROM_END EQU 021FFh

page 17 of my data sheet shows that bank 2 ends at 16FH not as it says above, 1EFH , could this be the problem or am I missing the obvious ?

What do you think ?

edit.

I have just changed the bank 2 end location to 16FH from 1EFH in the 648a.bas file and recompiled using the program in post 14, with the clear in position.......it works perfectly... so do you think I have found the problem ?