Sources for 8b TTL keyboards (Keytronics)

Chuck Guzis cclist at sydex.com
Sun Dec 7 17:47:41 CST 2008


On 7 Dec 2008 at 23:29, Gordon JC Pearce MM3YEQ wrote:

> >    Jules, I work developing hardware for a living, and I'll tell you 
> > something: If you are used to Z80, you'll have a hard time using a PIC. 
> > But an AVR will be easy to you to swallow.
> 
> The PIC is one I always found interesting, in that it's generally easier 
> to program in assembler than C...

Eh, there's not a lot of difference.  The AVR's more orthogonal in 
use of registers than the PIC (which seems to run almost everything 
through W), but the AVR's got its own peculiarities.
 
I'm just starting with the TI MSP430 and I like it a lot.  Von 
Neumann archicture, instead of Harvard.  16 general-purpose registers 
with a simple 2-address instruction set that operates on words or 
bytes.  R0 is PC, R1 is SP, R2 is status. Indexed and autoincrement 
addressing modes are available.  If you're used to traditional 
architectures, this one's very easy to learn.  But it's got its 
drawbacks also--upper-level AVRs allow for external memory, but the 
430 seems to be architecturally limited to no more than 10K of RAM 
and 60K of program ROM, which should be sufficient for most tasks.  
Very low power 3.3v operation; not available in 5v versions.

Cheers,
Chuck
  




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