Sigma studio program protection.

Hello Tomdy,

This is good question and there is not an easy answer.

If you are concerned that someone can read the EEPROM and then reconstruct the SigmaStudio schematic from the image then you do not have to worry about that. We would have difficulty doing that here where we designed the part! There are no reverse compilers and we do not give out the machine code and very few people have the assembler for these devices.

What is a problem is that someone can exactly copy the hardware and then copy the EEPROM and then it would work. They would have successfully copied the product. Making changes in the program would not be possible but that may not matter.

Now with some of our devices there are some techniques to make this more difficult or impossible. I do not know what others have done since they do not tell me and if they did I would not put them up here. If there is a controller in the system then you can implement some protection there. You can use a GPIO to signal the DSP program to operate or to mute the audio. If the signal is not there then it will mute.

If your production is not too many units, then you can use SigmaStudio to program the EEPROM for every unit. Then you can program into a DC cell a serial number. This would change from unit to unit of course. Then the system controller can also be programmed with the serial number. Then on power up it reads the DC cell and if they do not match then it will not operate. You can do the same without SigmaStudio by simply storing a serial number on the EEPROM and having the system controller look for it.

You could compile the program with outputs muted ( a good idea anyway) and possibly with other cells having default data like an EQ. Then on powerup the system controller would change the settings and load the filters. This would be a little more difficult to copy.

Without a system controller it is difficult to protect the program from being copied and run on identical hardware. With a system controller you can use its copy protection scheme and have it program the DSP or simply activate it as I mentioned above.

In SigmaStudio there are some ways to protect and hide parts of the program so that you could have a version for installers and a version for designers. But I know this is not what you are asking about.

If anyone else on the forum has some good ideas to share please post other ideas.

Dave T

DaveThib said:
In SigmaStudio there are some ways to protect and hide parts of the program so that you could have a version for installers and a version for designers. But I know this is not what you are asking about.

Hi Dave

Can you share a bit more about where to find the information on this? It will be useful on some occasions.

...

Hello Tomdy,

You can start here by reading the Hierarchy Boards section of the Wiki:

https://wiki.analog.com/resources/tools-software/sigmastudio/usingsigmastudio/hierarchyboards

In there is shows how to "Hide" a board. This will keep honest people honest. It is not a way to fully protect the code but it will prevent users from going into controls that they should not be adjusting.

What you can do is use inputs and outputs from the boards to bring out any controls that you need to expose but keep the rest of the controls hidden inside the board. Then hide it. If you have the password you can open it, if you do not then you cannot open it.

Dave T

Thanks Dave

Hi Dave

Anyone form the community you can suggest to help me verify the firmware? I had a engineer develop the firmware use STM32 MCU. But I don't have proper tool and knowledge to verify the program. I hope to double check before I spend money to do a PCB board.

Thanks