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Support Forum » What am I doing wrong??
December 04, 2010 by Ralphxyz |
I am "trying" to set up a new NerdKit. When in program mode I get 1+1/2 black bars for 30 seconds and then a empty LCD. In run mode I get some random marks and then empty LCD. I cannot program or run programs. If I put the mcu into another NerdKit it runs and programs as expected so it has to be something I am doing! It will be embarrassing but I sure hope someone can see what I have done wrong. Thanks, Ralph |
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December 04, 2010 by hevans (NerdKits Staff) |
Hi Ralph, It is not very clear from your picture, but I think pin 11 of your LCD might be heading into the wrong MCU pin. It is supposed to go into MCU pin 4 (unless you changed the LCD code), and from the picture it looks like it's going into pin 2. Humberto |
December 04, 2010 by Ralphxyz |
Nope bad angle. Pin 11 to Pin4 Here is another angle of a new breadboard with the same results. I thought possible I had blown the breadboard but I am getting the exact same results with the new one. I have rewired this 6 or 7 times, all with the same results. Ralph |
December 04, 2010 by Rick_S |
Ralph, What are you using to power the kit? If it's an AC-DC power block, you might try adding some filter caps. I don't even see the .1uf at the power pins of the micro. Rick |
December 04, 2010 by BobaMosfet |
Ralphxyz- You've got to do a little debugging on this. Use your voltmeter (it is your best friend!). Try this:
Information is key. I don't know if you have an o-scope, but now is a wonderful time to really learn how to use it, if you have one. Please let us know what you find with your voltmeter! :D BM d |
December 05, 2010 by Ralphxyz |
I am using a Dell PDA 15 V 2.0 amp brick power supply which I assume would have a filtered supply. But good eye Rick I had missed the bypass capacitor on that new setup, I have since added it with no difference. Here are my multi-meter readings with comparisons to a working NerdKit (I have two working Nerdkits but I want to start on the LED-Array project so wanted a dedicated breadboard).
How would I see a voltage drop across the display? I just see rail voltage. Would I have to put the meter in line like to see amperage or I added a 1k resistor in line with the Gnd coming from the LCD and see 1.45 v. Is that what I should see? Working Nerdkit readings:
Looks the same. Ralph |
December 05, 2010 by esoderberg |
Ralph, On the second picture, I don't see a connection between SPDT switch and ground. Eric |
December 05, 2010 by Ralphxyz |
Yeah Eric that was because there wasn't one, duh good eyes. I rushed that setup and didn't do normal things and still got the same results. In fact my bread board requires a jumper in the middle of the rails on both sides which I didn't have so I also was not feeding VCC directly to pin 7 or pin one which I discovered thanks to BobbaMosfet exhortation to test everything with my multi meter. Even without the capacitor, switched pin 14 or direct power to pin 7 I was getting the same results as on a good NerdKit breadboard. It appears I have a bad LCD display as I can program the mcu with a LED Blink program and it runs correctly!! I have removed the LCD wiring so I am loading the program blind but the program is loading I have loaded a couple of different programs on different devices and they all run! So I think I am good to go, now I can start on the Led-Array project. Thanks everyone for the help. Ralph |
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