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Re: [Homebrew_PCBs] LQFP48 package PCB success!

2006-01-31 by Stuart Wallace

Hi Leon,


Last year I made a small rectangular single-sided board containing an 
LPC2105, some decoupling, a 1.8V regulator and the crystal and its 
associated caps. I brought all the GPIOs out to the longer edges of the 
board and soldered in some long-pin SIL strips so that the whole 
arrangement is like a DIP48 package. It worked well for prototyping -- 
I've got it plugged into a stripboard, with an MMC card (7.5MHz clock) 
and some other peripherals hanging off it. It seems to work flawlessly 
-- I still use it most days.

I guess the point is that it's entirely feasible to put something like 
what you propose on single-sided FR2 board and run it at a reasonable 
speed. The off-board MMC port runs at 7.5MHz (the cpu's limit given a 
60MHz cclk) without errors -- I guess that's the fastest signal on my board.

My process was photo-etching (Canon i560 for artwork, generic 
transparency sheets, DIY UV box, DIY bubble-etcher with FeCl3 etchant, 
cold-plated the board etc) and hand-soldering with my bargain-basement 
17W Antex iron. It took about an afternoon to build and populate the 
board and bring it up -- I was pleasantly surprised!

I think I recognise you from the LPC group :)


Stuart

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