I am using a MCB900 kit with a LPC935. Running with the on-board RC oscillator and divided down to 0.52Mhz.
A 16x2 VFD and a LED on P2.0 acting as a heart beat indication and a few push buttons is all in terms of I/O. Required code worked fine. Till I wanted to save the hassle of changing the RUN and RESET jumper for every code change. I wired a DPDT switch using 4 wires of 150mm length and 0.25 sqmm size and plugged it onto the jumper pins using a relimate connector.

Changing from RUN to RESET to RUN was now a breeze. BUT, the VFD no longer worked and the kit did not connect to Flash Magic. The LED connected to P2.0 however was pulsing at 1 Hz without problems.

Remove the switch and go back to the small jumpers - all work as expected - VFD, FlashMagic link up etc.

Any guess whats going wrong ? Capacitance of the wire lengths spoiling the reset pulses ?? But then why does the VFD stop working ??

Thanks

Raghu