In my case, the SRST or SRESET signal (pin 11) on the 16-pin ribbon cable of the programming tool had to be disconnected. While programming, the programming tool is supposed to externally drive this signal to ground. Per the CW TAP User’s Guide, the signal may or may not be wired to the target processor. I discovered that during programming this signal doesn’t appear to behave properly as it gets “stuck” at approximately 1 volt instead of ground or 3.3 V. At 1 volt, I believe the processor is being held in a reset or possibly indeterminate state and disallowing it to execute any flashing algorithm.
