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. Regards Ken. +-----------------------------+----------------------------------+ | ken hewitt | Email ken@welwyn.demon.co.uk | +-----------------------------+----------------------------------+