I am working with a new board that uses the ADuC841 and has an on-board RS-232 line driver (ADM3202). I am able to RESET the part successfully using the WSD PC program. However, when I attempt to download, the part fails to erase code and data (after successfully resetting the part). Of course, this prevents the download from proceeding.
I have checked both the transmit and receive lines with a scope, and both appear to be successfully managing the comm signals, both at the chip level and through the level translator. It simply appears as if the chip does not properly execute the erase command.
The master clock is 11.0592 MHz and the baud rate is 9600. The system has a 3.3V rail.
Any ideas about what might be causing the erasure failure?