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Standalone Nightmare

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As many nightmares evolve, I find myself alone in a state of terror with my MSPG452 project.

I look to you guys for some comfort :o


I have a basic input/output project that functions perfectly on the stock launchpad...

The code is not the issue, the problem lies in my lack of EE experience...


I have been working at this for about 6 months (learning and getting favors from my friend the programmer) :




I picked up some expensive FR4, they are pretty and have "cuttable" connections between all the positions. A little bit of a pain at first, but I can appreciate the idea- less jumpers and solder. You need a brand new utility blade for starters, and a good layout in mind. You can see an issue with the couple of wires on the face.




this progressed to a much prettier prototype (took about 2 hours):




It was heartbreaking when it did not work, nothing happened. Then Ken Finnegan alerted me somewhere in his many posts that the standalones need to have the reset taken up with a resistor or it will continually reset. Thanks Ken (great name by the way). Done, and i had some flashers.


Unfortunately, the inputs and the outputs are not working like on the LP. I have traced all my connections, and checked for shorts and gaps, and found nothing. I am able to hardwire the inputs, using a jumper, a switch, or my finger, but for some reason, the P1.0 input will not trip the interrupt now- but all the others work (P1.1-P1.3). Your comments are welcome, please!

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thanks zeke, that Is a great reference. All seem to agree on the cap, which i will add momentarily. Can you tell me what OR means please. I am going to include a jumper as you show so that I do not need to keep switching the chip out (it was on my todo/tofigureout list :P )


P.S.- how do you put the images directly in the post. I tried the button (Img) above, and put in the link, but it didn't do anything.


Thanks again. Ken

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Yeah, like BH says, it's a zero ohm resistor.


When you're laying out a pcb and you're going to use surface mount parts, you might as well make the design as generic as possible. This will let you use that pcb for a new circuit later on down the road.


Putting in a zero ohm resistor will allow you to disconnect the micro from the circuit and then you can solder in something new.


Compare your circuit to the diagram.

Do you have the reset line pulled up with a 47Kohm resistor?

Do you have 3.3 volts connected to pin 1?

Do you have ground connected to pin 16?

Do you have your chip inserted with the correct orientation?

Can you program your chip with the launchpad?


If you are trying to program the target board with the launchpad then make sure that you remove the micro from the launchpad. If not then remove all the 0.100" jumpers from the launchpad's spy-bi-wire connector (J2) and then use the 0.050" connector (J4) and connect to your target.


Simplify your setup and it will work for you.

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I am going to try and enable the resistors. A while back this helped me with a bouncing problem. I have hardware debounce now, but I am going to give it a shot.


I have checked off everything on your list zeke. I have been programming it on the LP and then hooking up my wiring harnesses to the LP to test it- working fine, I move the chip to the PCB. I am thinking now the problem is with my buttons. I based them on the demo: http://processors.wiki.ti.com/index.php/MSP430_LaunchPad_PushButton


It must be the debounce circuit. Curious why it works fine on the LP and not on the PCB :cry:



thanks again you guys!

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Here are some late night drawings, I will work on some better ones tomorrow... Thanks

Using MSP430G2452, detail per aforementioned wiki example


Anyone have a schematic program that is free? PCB artist was ok, but schamas were difficult to understand for me :roll:

J1=button harness

J2=LED Array








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The nightmare is over. After finally making a plan and working out a new board, being careful with everything and checking it twice, I can see the light. P1 resistors enabled. The help is greatly appreciated, and the button debounce works flawlessly (no extra ints). Resistors enabled on P1.0-P1.3.


Working with those connected PCBs it not worth it in my opinion, although the product is very appealing to the eye. I will improve on the board with a jumper for programming next..... : :)




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