I am having problem getting the ADuC7020 to perform serial download using UART. I believe I have properly set the processor into the serial download mode by holding the BM pin low, then reseting the processor, then releasing the BM pin to High. After that, I sent 0x08 from the host PC, but I am not getting the ID string responded back from the processor.
I know the physical serial connection between the processor and the host PC is good and functional. This is because I downloaded a UART firmware driver into the processor via JTAG, and this firmware driver is able to echo characters that I enter from the Host Hyperterminal. Therefore I know my serial connection is good and functional.
After that, I set the the processor to serial download mode as described earlier. Then I no-longer see characters echoed back to Hyper Terminal. This suggests that I was successful in placing the processor into the serial download mode. I also did necessary probing(i.e, probing the RESET and BM pins) in order to make sure I did the correct steps in placing the processor into serial download mode.
Any idea why I am not getting the ID string back? Is it because my parts are not for UART serial downloading? How do I tell whether my parts are for UART downloading or I2C downloading, or do not support serial downloading at all?
Thank you for your inputs.