If P0.3 on the ADuC7024 is configured to have the ADC_BUSY function could this cause JTAG access to be locked out, as that pin's function is also JTAG TRST?
Since doing this I get the following message from a programmer "TCK(pin 9) low, but should be high. Please check target hardware.".
If locked out because of this, I assume the only way to recover is to perform a mass-erase with ARMWSD.