Ken Hewitt wrote:

> Can anyone tell me the requirements for programming the C54 in circuit,
> what do you need to do with the MCLR pin. I can't find any data in the
> microchip data book. I take it that the C54 can be programmed serially
> as it can be programmed with the D. Tait type of programmer.

There is a Tait programmer for the C54:

http://www.man.ac.uk/~mbhstdj/upp.html

However it's not intended to program the chip in-circuit as the C54
cannot be programmed in serial mode.  That doesn't mean you couldn't
come up with a circuit to do that (I'm sure Andrew Warren said he once
worked with such a setup) but I doubt if that's the best way forward
nowadays with such a gamut of alternative PICs available.

David