Design a replacment Upgrade-PCB

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The number of hardware mods required for some of the more advanced extras -- 
like mass storage and mp3/apcm audio for telemetry etc -- are becoming too 
tricky to handle on the original PCB.

One thing I want to do for example if reconfigure all the trims and button 
switches into a 8-bit 4x4 scanned matrix, in order to free up most of PORTB on 
the ATmega. This requires disconnecting all the existing switch GND circuits 
and has proven impractical to do on the stock PCB, without major butchering.

Then there's the already 'fiddly' changes just to free up USRAT0 for telemetry 
data, and even more tricky stuff to free up USART1. These mods alone are too 
tricky for all but the most steady-handed and skilled soldering-iron wielders I 
should think.

We're also going to need more programming space if we want to implement mass 
storage without having to purchase relatively expensive external modules.

I've got a sneaky plan for a 3D PCB that would replace the ATmega with a '128 
version while also breaking out the new connections I'm using. But, there will 
soon come a time when a completely new PCB starts aking a lot of sense. 

Preliminary work has already begun on this, with low-volume Chinese 
manufacturing lined up for the future to keep costs down. Time frames are 
completely unknown at this stage.

But really, why? Well, I want to take this project as far as it can go -- 
especially in the telemetry context. If I don't lose motivation through lack of 
interest from others, some pretty cool things emerge in time.

Original issue reported on code.google.com by gru...@gmail.com on 18 Nov 2010 at 12:42

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PCB rev2.141 was sent to the factory for fabrication Dec 17, 2010. Ten boards 
expected back by Jan 11th, 2011. Components to construct up to 3 prototypes for 
testing and debugging have been ordered. Construction expected to be complete 
sometime mid to late Jan 2011.

Original comment by gru...@gmail.com on 20 Dec 2010 at 8:49

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2011-01-14: The prototype 2.14 board is fully assembled and working. A number 
of changes, mostly around the wiring positions of the trim switches, have been 
noted for the V3 board. The telemetry pseudo-RS-232 port is working fine. An 
RTC (real-time-clock) needs to be added. The extra 2048bytes of EEPROM have 
nicely extended (almost doubled) the model and settings memory. Unfortunately, 
I had to increase the block size -- or go 16-bit for the allocation table. So 
raw data from a 2048byte EEPROM is not compatible with the new OS code. I might 
work on a conversion program some time, but it's frankly not so likely to be 
any time soon. Anyone else care to take this one on?

Next step is MM/SDCARD mass storage interface and coding (and RTC).

Design changes for the V3 "final production" board (hopefully) will be carried 
out as we move along. I don't want to rush this one. Need to get it "right", 
first, well, second time. :-D Besides, I'm fresh out of cash to pay for it 
anyway. 

Original comment by gru...@gmail.com on 14 Jan 2011 at 8:11

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V3 design completed. V4 design underway. Signing off this issue, since it's now 
a core part of the entire project.

Original comment by gru...@gmail.com on 9 Jul 2011 at 1:19

• Changed state: Done

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Original comment by gru...@gmail.com on 23 Sep 2011 at 1:50

• Changed state: Verified