I use pin 3 of port 1 (P1.3) on my products and at power up, the port is in high impedance, everything is ok.
Now we received a new reel of aduc7021 and this port (pin 1.3) now emit a glitch at power_up : 2V during 17ms with a pull down of 68Kohm.
My application doesn't work now!
Do you have changed something? Is there is a solution?
can you check where this parts are coming from - a legal ADI distributor?
Also can you send what is printet on top of the part - possibly a photo ?
What is connected to the pin - 68k to GND?
I have found my problem, the BM pin is not tied to supply. I have considered that the internal pull-up was enough to start program.
When I added a resistor to this pin the ADUC starts.
Can you confirm that?
The ADuC702x datasheet recommends pulling the BM pin through a 1kOhm resistor for code execution in the pin description section. However in most cases the internal resistor is sufficient.
Could you confirm what model of the ADuC7021 you are using, i.e. the UART downloader version or I2C downloader version? Are the markings on previous devices and on the new devices similar on the third line (I51 or I31)?
On previous and new devices the markings is the same I31.
I had a NMOS transistor to drive this PIN and the leakage current must be enough to pull down this PIN.
The NMOS is drived through P1.3, if I deasable the Pull-up in the GP1PAR register does it change the port At power-up?
disabling the pull up in GP1PAR will only disable it after code execution. at power up GP1PAR is configured with its default value i.e. pull up enabled.