There are several steps you need to take.

1. Get an 89LPC935 and build the same circuit that is on the Keil MCB900. There is a link to the schematic diagram on the Flash Magic web page. If this is a one-off then it's probably quicker, easier and cheaper just to buy an MCB900.

2. Program the 89LPC935 with the ISP to ICP bridge code. Again, the hex file for this is linked on the Flash Magic web page, in the Third Party section. You can program it using Flash Magic.

3. Add the circuit diagram in the Philips ICP application note to the MCB900 (or equivalent). This connects the 89LPC935 acting as the bridge to the 89LPC915.

Now you can program the 89LPC915 using Flash Magic.

Andy