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About Hydra schematics and DNP parts


Hi people,

I have been developing a huge project around an Hydra board. Now, I need to make my custom Hydra board for design requirements and lack of space in the housing.
Today I realize that Hydra is not totally open source, some parts are named “do not populate”. My question is about IC2 (see picture attached).
Supposing I find another serial memory, will my board work like an Hydra? Has this memory a kind of BIOS or something?

I don´t want to waste my time working in this board if it won’t be a copy of an Hydra.



Not totally open source?! You have schematics, software, eagle and even the physical board if you wanted to double check something. What is missing?


Really ? Hydra is so open that you dont have to use the schematic at all. You can design your own board with the CPU BGA, SRAM, Dataflash. The only extras may be decoupling, main clock and RTC.


“do not populate” is an instruction to a fabrication house not to put that item on the board. Does that have any actual meaning in a replica? probably not. As the others have said, it’s about as open as you can get !


The board is completely open-source, so you’re welcome to use whatever serial EEPROM fits your application. But if you change the part, you may need to recompile the firmware from source code using the NETMF PK with either GCC or MDK, which can be an intimidating process for beginners.

Before you change the component, ask yourself:
[ol]Does it have the same communication interface and memory organization as the original part? If not, you’ll need to download the (open-source) Hydra port, and modify the source code for the blockstorage driver to support the device.
Is it the same capacity as the original part? If it is smaller, you’ll need to change the Hydra’s scatterfile and recompile. If it is bigger, you can use the factory firmware, but you won’t be able to take advantage of the extra space without modifying the scatterfile and recompiling the firmware[/ol]

If “scatterfile” and “memory organization” are new phrases to you, I wouldn’t recommend changing the flash chip.