Re: How do I add firmware to a card?

["mdj" <mdj.mdj@gmail.com>]

David Wilson wrote:
> mdj wrote:
> > Oops, I intended that the Apple II itself would end up being a
> > programming device for the uC, such that the uC's firmware could be
> > replaced by a host program, thus facilitating upgrades etc.
>
> That is also possible (but would be tricky - the hardware interface for
> a programmer may be simple but I am not sure about the actual
> programming commands). For example the PIC programmer I use has an
> onboard PIC to do the timing critical stuff.

Interesting. Most are just a simple parallel port bit banger, which
works fine. I thought it was merely a case of serially feeding the data
to the PIC after setting it into programming mode.

Of course, somebody would need to write a PIC programmer in 6502
assembly, although I doubt this would be all that difficult.

> > Of course, this isn't useful functionality in the development cycle,
> > but it's handy post-production, since regular users could then "flash"
> > their devices to handle the latest improvement.
>
> Actually it is useful during development - no need to take card out of
> A2 to program the uC. I have some AT89C51IC2 uC chips which if I read
> the data sheet correctly have an onboard boot loader and can be
> programmed through the on-chip serial port.

Very true. I think the hardware programming interface to almost all the
smaller uC's is pretty trivial, it's the software that'd be the big
issue.

Matt