Normal Operation?

rickalvi

I am working my way through the What is a microcontroller book. I am using a BS2 chip and a BOE Board Rev C. I am connected to my computer via a Parallax USB Adapter. I am just starting the blinking experiments. I am encountering problems with board recognition on the COM Port. After several trys it finally recognizes the board at COM PORT 5. I usually have to try several times before it is finally recognized. I have noticed that when I turn the board, on without running any program, The board is just connected to the USB port, the LED presently connected to pin 14 via 470 ohm resistor going to Vss blinks on and off. Is this normal? Also the RED LED on the USB Adapter continues to blink. What does that represent? The present program that I am running on the BOE is the simple FOR NEXT from ACTIVITY 3 Counting and Repeating. When I run the experiment I usually have to press the reset button twice to cancel out the blinking then it runs everything ok. Goes back to random blinking after the program ends. Pressing the reset button any number of times does not stop this. Any body have this problem or is all this normal?

Duane Degn

The LED connected to pin 14 is blinking since the last program loaded to the BS2 is telling it to do so.
The last program loaded to the BS2 will still be in its memory when it's turned back on. The BS2 doesn't need to be connected to the PC to run this program. So the blinking LED is normal since the BS2's program is causing it.
I'm guessing the program also has a debug statement which is causing the red LED on the USB adapter to blink indicating the BS2 is attempting to send a message to the PC.

I'm not sure what to tell you about the board not being recognized. My theory is the communication coming from the BS2 interferes with the PC's ability to recognize the port. I don't use the BS2 much but I have a similar problem with the Propeller. I usually just try a couple of times. Pressing reset on the board right before sending the program usually works.

RevC

Hello,

There may be an other application trying to use that port. Look for an application that uses serial port for communication. Close all programs that are running in the background, and make sure that you look at your system tray and exit out of any application that may be running and close them.

Long ago it used to be that programs that would sync with PDA's like the Palm Pilots or Windows CE. Applications that use bluetooth communication may also cause it as they use serial communication.

rickalvi

Thanks Duane Dgn, for your insight. You are right, and I should have realized it. Once the program is downloaded into the BS2 it remains so –Duh! It’s a micro controller. I verified it by disconnecting it from the USB port, turned the board on and it operated as programmed. Your are correct again the program does have a DEBUG statement on it. I deleted it and as you predicted the red light at the USB adapter stopped flashing. Oh and the program operated flawlessly without any erratic blinking. Apparently it also cured the COM PORT Problem. When I re-wrote the program eliminating the debug statements the BOE was immediately recognized and RUN immediately programmed the BS2. Thank you again for your wise insight and quick response.

rickalvi

RevC

Thanks for your insight. The only thing I had connected to any other port was my printer LPT1 and the printer was turned off. I will still keep your recommendations in case this problem surfaces again in some other application. As you can see by my response to DuaneDgn the problem was found and solved. Thanks again for your insight and quick response.

Publison

Glad you got it worked out, and welcome to the forums. We are a friendly bunch. Don't think any question is dumb. Ask away.