npitech

Just received my board -- problems!

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I received my Papilio (250k) a short time ago and started to go through the documentation then discovered I needed a MegaWing. It arrived today so I went through the steps and programmed the board with Switches_LED.bit. All of the 7-segment displays lit up and none of the switches control any of the leds (all off). Double checked everything and went to the forums where I find someone with a similar problem. There was a note about changing the code to address different pins (MSB vs LSB). Tried that; no change.

Tried Quickstart-Papilio_One_250K-v1.5.bit; all even-numbered leds blink, switches do nothing. I noticed that the behavior changed if I touched some of the pins near the switches. I could move my fingers around and get one, two, or three of the leds to stop blinking. Seemed to me like one of the supplies needed some more capacitance. Used my o'scope to check the supplies and found 5V was clean, 3.3V had about 400mV of a sawtooth and the 2.5V had a smaller amount of the sawtooth. Touching the scope probe to various pins causes different leds to stay on. The sawtooth changes from 20kHz to 47kHz at what seems to be the same rate as the leds turn on and off.

I inspected all of the solder joints on both boards, I didn't find any cracked joints. There were a couple of solder splashes on the MegaWing (not mine, I only soldered the connectors on the Papilio) and a large blob of solder wicked up on the leads of C3 but otherwise, the board looked good.

Any help?

PS. Won't be online tomorrow --

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Check your .ucf file, sounds like your inputs are not connected to the switches but left floating which is why they are affected when you move your hands on pins. I think the same suggestions apply here as they did for the other similar query in the forums recently at http://forum.gadgetfactory.net/index.php?/topic/1399-first-project-wont-start/

The ripple on the supply rails, while not ideal, should not be the cause of this, feel free to solder more caps if you want to reduce the ripple.

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If you still don't have any luck, check that the part code on the FPGA matches what you think it should be. then email ma (hamster at snap dot net dot nz) and I'll send you a BIT file that works for me on my board.

I'll also email you the entire project, so you can build it locally too.

I have had similar problems when I downlaoded a -500 bit into a -250 part. The bit file downloads fine, but the FPGA fails to configure corrently.

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Tried Quickstart-Papilio_One_250K-v1.5.bit; all even-numbered leds blink, switches do nothing. I noticed that the behavior changed if I touched some of the pins near the switches. I could move my fingers around and get one, two, or three of the leds to stop blinking. Seemed to me like one of the supplies needed some more capacitance. Used my o'scope to check the supplies and found 5V was clean, 3.3V had about 400mV of a sawtooth and the 2.5V had a smaller amount of the sawtooth. Touching the scope probe to various pins causes different leds to stay on. The sawtooth changes from 20kHz to 47kHz at what seems to be the same rate as the leds turn on and off.

Hello,

The Quickstart-Papilio_One_250K-v1.5 bit file was not meant to drive the LogicStart board. It configures every other GPIO pin as either LED output or pushbutton input, so it's meant to have a B/LED Wing connected to it. Unfortunately the inputs do not line up with the LogiStart pins so that explains why touching some pins will effect the LED's.

It brings up the good point that I need to release a Quickstart bit file for the LogicStart MegaWing though. Let me clear some things off my plate and try to get something together for you.

Jack.

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Thanks All.

This morning I edited the UCF to put the pins back to match the documentation (vs. the re-ordered pins to flip the msb/lsb) and suddenly I can toggle the switches and get the LEDs to turn on. I do not know what changed, in both cases I cut-n-pasted the text in the file but it looks like I can now proceed to learn more about these pesky fpgas. I'm an rf & uwave guy.

thanks again!

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Excellent news npitech! The first hurdle when starting out with FPGAs is a very high - even on a fully tested board. I can't imagine how hard it is to bring up a new PCB from scratch.

Things should start being much more fun from now on :-)

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