I am having a problem with a product developed with the LPC4337 uC. We make the USB conexion for ISP operations through a PIN header. Sometimes, after proceed to connect the USB in the PIN header, the uC dies, and can't be recovered. After that, no clock signal exists, and it is not possible to entry in boot loader pulling down the ISP pin, and making a reset. The uC is simply death.
Any suggestion? Is the pin connexion order so critical that can crash the uC?