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Microcontroller Programming » LED Array problem?

October 30, 2012
by wadaltmon
wadaltmon's Avatar

Since I have concluded that this is an MCU issue (MCU not sending response to computer), I have decided to put this thread here.

Hello, I recently set up my LED Marquee kit and went through the guide. I did all the code and transferred it to the MCU, but now, I am experiencing some problems. in the beginning of the program, it sends "NO DATA " to the MCU. All mine does is send the N in NO DATA, so I am assuming that my MCU is not sending the "n" back to the computer. However, I checked all my code and it is all correct. I also checked the Python code and redownloaded it to be safe. Still, it did not work. I used the LED array template program that comes with the source code that you can download. I transferred that to the MCU, but that did the same thing: It only sent the first letter, and then gets stuck on "Waiting for request..." in the CMD. I tried typing things in and pressing enter, but it doesn't really do anything.

Any ideas on what could be causing this?

Thanks in advance,


February 23, 2013
by Cmnemes
Cmnemes's Avatar

Hey there. I recently ran into a problem with my led array when it came to scrolling messages. Slightly different problem but maybe it will help. When starting it would send 'NO DATA ' except instead of sending just the 'N', as in your case, it would send a garbled mess. After spending much time looking at some python documentation, on line 34 of where it reads--

serial = serial.Serial(serial_comm_dev, serial_comm_rate)

I added 'timeout = 1' to the parameter list like this--

serial = serial.Serial(serial_comm_dev, serial_comm_rate, timeout = 1).

This cleared up all my issues and I can now scroll legible messages.

It has something to do with how many bytes the buffer can read at a time i think. I'm no expert at this and I'm not sure this is the correct or best way of doing it, but it worked for me and my problem. Give it a shot maybe it will also work for yours.

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