EPROM emulator

[Andrew K. Mattei]

steve ravet wrote:
> 
> Did you mean flash instead of eeprom?  29f010 is a flash part.  Flash
> parts can only be erased in sectors, which means you'd have to download
> 16K chunks at a time  At 9600 baud it would take about 17 seconds to
> download 16k.  Having a RAM means faster updates.

Ahh... ;) Well, that's what happens when engineers get stuck in the
marketing department. OK, how about NVSRAM? I have a Benchmarq BQ4015
sitting on my desk at work. It's a 4Mbit module. Here's my concern. I'd
like to leave the Eprom Emulator plugged in to the car. All the time. ;)
Not have to load it first - when I feel like tinkering, I plug in to the
RS232 port, tweak a few parameters, and then disconnect the laptop.
That's why I was thinking EEPROM... or Flash... or NVSRAM...

And, we need to be able to write to individual addresses, right? ;)


> 
> PICs have a serial port built in, and up to 5 I/O ports (8 bits).  The
> PIC alone can handle reading from the serial port and writing to the
> RAM.

OK :) PICs are something I'm interested in learning, too. So much to
learn, so little time... 

> 
> I have attached to this email a .jpg of the OE circuit I talked about
> earlier.  It's 10k in size...

Got it. Seems straightforward to me.

Seems, though, that we'll need a pretty big PIC to handle all the
address and data parallel to serial conversion... Looking at Digi-Key,
looks like the PIC17C42/43/44 might fit the bill... 33 i/o pins... :)
Still under $20, though.

Of course, I could spend all day dreaming up schemes... I look forward
to seeing any schematics folks may come up with!

-Andrew