At 11:08 AM 7/28/2003 +0100, you wrote:
> > What is the approximate time it takes to table write a byte to program
> > memory on the 18Fs? My requirements would be writing 8K of data (max) in
> > <100 ms.
> > Cheers,
> > Ishaan
>I would be very tempted to do this into an external I2C chip using one of
>the FRAM family, as they are not speed limited on write.
There are SPI versions of the FRAM chips. For example, the FM25640 is
8K x 8 and can operate at a 5MHz bus frequency.
It also supports sequential write mode (which I don't normally like
much, but might be just the ticket here). All you need to do is set it up,
then pump the bytes sequentially into the SPI register on any PIC with
hardware SPI- less than 2usec per byte, much faster than the application
requires, and only a few port pins consumed.