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Comment by rffn | Hacker News Reader

How open is this hardware? Are there open specs for Mali? Are there open specs for CSI and DSI? All this is on the board. Available specs are needed to write open source software or at least make it much simpler. I have difficulties to consider a board with missing specification for important parts or connectors to be "open".

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Well, then you must have difficulties considering almost any embedded board, because they all have a combination of chips with closed specs, or chips that require blobs to do important things, e.g. boot.

Is there a truly open board except the Lemote stuff?

I do not have difficulties considering the existing boards. I would just not call them "open", because specs are missing, blobs for some functions, etc. This board is advertised as open and my critique pointed towards that. Advertising non-open things as open does in my opinion hinder the progress to more open hardware. That's a bad thing.

The Beaglebone Black is the most open board, so far as I can tell.

Here are the PCB sources for the latest revision: http://elinux.org/Beagleboard:BeagleBoneBlack#Hardware_Files

The datasheet for the AM3558 processor is here, no NDA required: http://www.ti.com/product/AM3358/technicaldocuments

The bootloader is U-boot, which is open source, based here: http://www.denx.de/wiki/U-Boot

The GPU in the AM3558 is a PowerVR SGX530, which is not open source in any sense-- I believe that the Linux driver uses a binary blob (but I'm not 100% sure of that).

For comparison, the Raspberry Pi has open schematics (http://www.raspberrypi.org/wp-content/uploads/2012/04/Raspbe...) but not open PCB layout source files. There's a partial datasheet for the processor here: http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM283..., but you can't buy the processor from Broadcom unless you're willing to buy 100,000 or so.

Last time I looked, the proprietary bootloader for the Pi also had a license forbidding you from running it on boards not supplied by the Raspberry Pi Foundation.

That is true, for Broadcom's proprietary BOOTCODE.BIN, the (ThreadX-based) START.ELF VPU-side microkernel and their user-space graphics driver components which talk to it via the Linux kernel shims. (Although, note: you won't get a BCM2836 anywhere else anyway.) Broadcom do, however, have someone writing an open firmware I understand - definitely an unfamiliar world for them, so let's give them time and see what happens.

I am also aware of a complete reverse-engineering effort (for the purposes of interoperability), and that is all I'm going to say about that right now. :)

Olimex has products that stack up similarly.

> For comparison, the Raspberry Pi has open schematics...

For the Model B rev 1.0 only. The B+ only has very partial schematics available (link below), and there's nothing at all out there for the 2.0 yet.

http://www.raspberrypi.org/documentation/hardware/raspberryp...

Minnowboard Max is also open.

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