AVR-Chat

Yes, and no.  You can certainly bugger a chip using the ISP (In System
Programmer) which usually, but not always, shares the SPI pins.  Then the
only way to fix the chip is to do parallel programming with (typically, but
not always) +12v on the reset pin.  That would be impossible with a TQFP or
MLF chip...  And probably impossible with SOIC and DIP depending upon what
is connected to the various pins.

Having a bootloader would avoid the above possibility since, AFAIK, the
chips don't have the capacity to self program the fuse bits (which is where
the problem lies as you can disable ISP and crystals, etc).

Other than that, the ISP interface is automatic and something like Avrdude
would be a good tool to up-date your chips - as long as you stay away from
the fuse bits :)

Some boot loaders implement the STK500 protocol so the chip will talk
directly with AvrDude over a serial line.  This is probably the cleanest way
to do a field update.  Check out: http://avr1.org  I have never used Jason's
stuff so your mileage may vary.

Cheers!

-----Original Message-----
From: LightYearCS
...
So like um...  using the SPI interface connected to a port will allow me
to upload the program to flash.  This is an automatic thing right?  I
mean, there is no boot loader program needed?  And this always works,
meaning, there isn't any chance of wiping some memory or register where
this upload process will stop working?

So, really SPI is it right? :)