LPC922 & Fash Magic-only writes once

[sanjayb]

hello,

         I am working with p89lpc922 isp mode, I had use the circuit which is as given on flash magic web site,
         But from some hardware difficulties it cannot give the reset pulses to enter in isp mode,
        are any other method or circuit to enter in isp mode

[Andy Ayre]

Which circuit are you using? The Keil MCB900 one? If you take a look at the Flash Magic application note on ISP entry using COM port handshaking signals, there is a description of how the circuit works along with expected waveforms at various points. This should give you enough information to be able to debug your version and find out why it doesn't work.