I have LPC54608's Evaluation Board(OM13092). I want to program it via my custom programmer and I use Flash Magic. My custom board is simple. There is USB to UART serial converter.
I am connecting related pins on my custom programmer with Eval board's related pins. ( There are P4 header on board and GND, TX ( P0_30_ISP_FC0_TXD), RX (P0_29_ISP_FC0_RXD) pins on it.
I connected my Eval boards RX to Custom boards TX, other TX to RX and GND to GND.