Future debug board and deprecating write-only

[Wolfgang Spraul]

Andy -
I LOVE this idea. Let's see what others & Sean think.
Please watch out that we don't forget this when doing the next design.
Ideally you could add it to the Engineering timeline for yourself,  
somewhere in the future.
Then it won't get lost...
Wolfgang

On Mar 11, 2008, at 5:21 PM, Andy Green wrote:

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> Hi folks -
>
> I awoke today putting two and two together about how I think we should
> deal with NOR, brickage and the debug board in future.
>
> Taking GTA02 as an example, what I would have proposed if I realized
> this earlier would have been to throw out the NOR flash completely.   
> Now
> the people that like the NOR flash defend it as the ultimate safety
> against brickage, however that is not true.  JTAG is the genuine
> ultimate safety against brickage already.
>
> A better solution would have been to throw out the NOR and place an
> internal USB micro B socket on the PCB (not reachable while in the  
> case)
> where the debug connector is now, and with the dual FTDI as found on  
> the
> debug board.  In short we place a "debug board" on every main board in
> the region that has the debug connector right now.
>
> It seems from discussing this with Werner in .tw that much of the
> current debug board is waste, for example the whole USB hub, the two  
> USB
> A connectors and probably a bunch of other stuff.  If we just placed:
>
> - the FTDI chip
> - micro USB conn
> - 6MHz xtal
> - EEPROM
> - 74*125 dual buffer
>
> on the main board, *every* phone would have a "debug board" built in  
> and
> can be debricked, and the cost is likely about the same as the NOR  
> flash
> it replaced for better functionality (and the removal of the need  
> for a
> debug board as a product).  There appears to be space enough  
> considering
> the NOR disappears.
>
> Then the complaint would be that the host-side tools are very poor...
> well crikey the amount of time we spent dealing with NOR U-Boot we  
> could
> have fixed that for a much wider and longer-lasting benefit.
>
> Getting rid of the "debug board" as an item and integrating it into  
> the
> main board is also a good way in terms of making every phone more
> hackable directly.
>
> - -Andy
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