Hello, I have a PLD that has a program loaded onto it, and the code has been lost. Is it possible to use Max+Plus to load the vhdl code from the chip so that the code can be used to program other PLD's?

--- Quote Start --- Hello, I have a PLD that has a program loaded onto it, and the code has been lost. --- Quote End --- How complicated is the code? Do you have a specification for what the code is supposed to do? Is it worth reproducing it? --- Quote Start --- Is it possible to use Max+Plus to load the vhdl code from the chip so that the code can be used to program other PLD's? --- Quote End --- If the code is for a device where the image is stored off-chip in a configuration memory, eg., an EPC2, then I believe it would be possible to read the image back (not the VHDL, just the bits in the device), since that is what the verify operation does. I suspect the same thing is possible with the MAX PLDs as well. However, I don't think it is directly supported in any of the tools ... I don't recall seeing a 'copy image to file' option in any of the programmer tools, however, you might be able to use the Jam STAPL player to implement image readback. But you need to decide whether the effort to implement image readback is greater than re-implementing the design that you've lost the source code for. I would recommend gathering the requirements for the design, then writing the code again, and then check the code into a code repository! :) Cheers, Dave

Even if you could read the bit file back from the flash, you'd have one hell of a job trying to reverse engineer it. Like Dave says, it doesnt store the source, only the bit file. Basically, without the source code, you're scuppered

IIRC, MAX and MAX II CPLDs don't allow the bitstream to be read back.

--- Quote Start --- IIRC, MAX and MAX II CPLDs don't allow the bitstream to be read back. --- Quote End --- They do, if protection isn't set.

Ok, after doing some more searching, I found an old compilation report. Would information such as what is shown below be able to be used to recover the code? -- Node name is 'AD2' = ':246' -- Equation name is 'AD2', type is output AD2 = LCELL( _EQ005 $ GND); _EQ005 = A1 & !_LC105 & T02 & T04 # _LC105 & _LC126;

Use Max+Plus to load program from PLD? | Altera Community

12 Replies

Altera_Forum
Honored Contributor
14 years ago
--- Quote Start ---
I have the .pof file.
--- Quote End ---
If you have a working board, then you should be able to use Quartus to verify that this .pof file is the one currently burned into a working board.

--- Quote Start ---
I would rewrite the code but the problem is that it was written 18 years ago by someone else. I'm just the middleman in this whole thing so I'm not even sure what the code does.
--- Quote End ---
Right, so its really up to you how important having the source code it. You could arguably consider the PLD to be a chip. If it does what you want, then you're done.

If however you have to change functionality, then you'll have to rewrite the code.

Cheers,
Dave
Altera_Forum
Honored Contributor
14 years ago
Ok, thanks. That helps a lot.

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Use Max+Plus to load program from PLD?

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