While familiarising myself with the LPC812, I disabled all the fixed functions via the switch matrix. As a result, my LPC812 can't be connected to with LPCXpresso. I tried to enter into ISP mode using the instructions here: ISP Reset over debug . But that does not seem to work. I hypothesize that it's partly because of both SWDIO and SWDCLK both being disabled. Is there anyway to reset the switch matrix to regain debug access?