Electronic badges

[Colin McGregor]

--- phiscock-g851W1bGYuGnS0EtXVNi6w at public.gmane.org wrote:
> > As noted in my posting about the Ontario LinuxFest
> I
> > am opening up the electronic name badge can of
> worms
> > again. So, with that in mind let note the
> strengths
> (snip)
> 
> To anyone considering a single-chip microprocessor
> project using the PIC,
> I would strongly recommend looking at the Atmel AVR
> series of
> microprocessors. The Microchip PIC is arguably more
> popular, but - based
> on my experience implementing code on it and the AVR
> - it has some serious
> architectural deficiencies.
> - limited number of instructions leads to opaque
> assembly language code
> - bank-switched registers and paged memory make for
> convoluted code and
> complex debugging environment
> 
> Anyone who challenges this is invited to write a
> routine that simply pumps
> out a section of memory to a host computer. On the
> AVR, it's about three
> lines of code. On the PIC, it's an ugly,
> non-intuitive hack.

On the BASIC Stamp the oddities of the PIC chip is
hidden behind a BASIC interpreter. So, I have not
written any PIC code...

Oddly enough the LCD name badge problem is a variation
on what you describe. The LCD module has some limited
smarts, so we don't have to worry about dealing with
individual pixels (well, subject to conditions we can
if we want to...). We want to walk through a block of
memory, feeding information out to the controller in
the module, toggling two control lines, and we want to
do a lot of waiting (even the BASIC Stamp could update
the display so fast as to make the display a blur, so
waits are a must).

> A compliler can hide many of the architectural warts
> of the PIC, but there
> are good reasons for projects of this type to work
> in assembly language.
> The code size is smaller and C tends to hide certain
> types of bugs.
> 
> Comparable IC's and development systems are
> available for both devices.
> Prices are similar.

I have an old PIC programmer, not sure how many
current devices it supports. But regardless I suspect
that if this is all a one person show it may not get
done. So this is why I got a kick out of:

 www.instructables.com/id/E5H5UDWB5UEUKIKV8V/?ALLSTEPS


A very bare bones AVR development system for about $10
(U.S.). Even that modest sum can be slashed if one say
has a parallel printer cable they are willing to cut
up. In other words a development system cheap enough
that building 2-3 (or more) will not be an issue :-) .


Beyond that just add Linux, a PC with a parallel port,
and some free development tools.

Colin McGregor

> Peter
> 
> -- 
> Peter Hiscocks
> Syscomp Electronic Design Limited, Toronto
> http://www.syscompdesign.com
> USB Oscilloscope and Waveform Generator
> 647-839-0325
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