I finally got around to building a few BPv4c's from the group buy we did 6 (!) months ago. I am making 3, and am encountering some problems running the self test. I was hoping someone would be able to help interpret the results to guide me in looking to see what might need to be re-soldered.
The first one reports an SDA failure, and then locks up on READ & WRITE.
The second reports: PULLUP H FAIL Bus Hi-Z 1: MOSI FAIL CLK FAIL MISO FAIL CS FAIL
The third reports the same as the second, plus also Vusb(0.00) FAIL.
Can anyone set me in the right direction? I couldn't find a guide for investigating failed test results. My next (and last) resort is looking at the source to try and see what the self-test is doing.
Here's my ATX breakout board assembly. I am not happy with the binding posts, but I had them from another project, and couldn't find better ones here in town for less than $3 a pop, so I'll wait until I can find a deal or have a mouser or digikey order to go out.
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I also used a random SPDT switch I had around, but it fit perfectly.
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I've checked it out, and everything works. I got the polarity on the -12V LED wrong, even though I thought I knew what I was doing.
I've already used it to power a number of projects.
That's an old Tim Weisburg album I got at some garage sale. I really need to build a light box or something, until then, enjoy the random backgrounds of whatever is on the most well list surface I can find when it's time for a photo.
I wanted a BPv4, and I thought I'd update it for the 'Sick of Beige' case series.
I chose the DP6037 footprint. I had to bring the IO connector in a bit, but otherwise, it fit pretty well. I had to move a few vias and things near the keepout areas, as well. I updated the date (2012 Sept from 2010 Jun) and updated the version number (4v2 from 4v1). The IO connector will be right near the edge, but I don't know how much clearance will be needed between the board and the top of any case in order to make the push buttons accessible. It probably needs some further refinement.
I'm thinking of making a Seeed Fusion order. PM me if you would be interested in a spare PCB, if I have any.
Caveat: These files are in Eagle 6.2.0 format.
[edit: deleted attachments, should have found ones in SVN instead]
You can sign up and submit your gerbers (or Eagle .brd files, up to version 6.2.0) and it will do some analysis, determine the cost (it's still $5/sq.in. for 3 copies), and show you each of the layers (rendered with the classic purple color, where appropriate). It will save the projects you submit (presumably, to allow easy re-ordering?) and the payment processing is all on the same site (paypal or google checkout).
I've used Laen's service in the past, and it's been really good. This looks like a major improvement, I've just submitted my first order, so we'll see how it all turns out.
I just put together my XC95144XL CPLD Breakout board. This is much like the XC9572XL, but with twice the macrocells.
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Observe the sideways SMT-A package 10uF tantalum cap on C14 -- I can usually put an 0805 cap on 0603 pads (or vice versa) but there was no way this was fitting. I did manage to connect the pads once I put it up and on its side a bit.
I didn't populate the top headers -- I forgot to include them in the order with the IC, and didn't want to wait for another order to come in. The TQFP-100 package was really hard to solder this time -- the first time I tried it, it didn't line up as well as I thought, so I had to redo it all with my hot air rework station. I also skipped the external clock. I have one more of those crystals, but I've had a lot of trouble soldering them on, so I thought I'd wait until I needed it.
I'm going to try to work through some of the tutorials to make sure I can get it to work. Maybe with this one, combined with the other, I can get that discrete logic I2C thing working...
I'm having trouble isolating a short-circuit on one of my projects, and I keep going through fuses (it has its own transformer, rectifier, and fused AC input). I wanted a resettable fuse board so I could figure out what was causing my blown fuses.
Here is the board I came up with:
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It's got terminal block and USB B connector input, terminal block and USB A connector output, a terminal for multimeter probes (for current measurement) and a bypass, a "power good" indicator LED, and a "fuse tripped" indicator LED.
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The "fuse tripped" indicator is the most interesting part of the circuit (to me, anyway). The P-channel MOSFET source is on the near side of the PTC, and the gate is on the far side of the PTC, pulled down to ground. When the current through the PTC is less than the trip current of the PTC (250mA), the voltage drop across the PTC is negligible, and therefore the voltage at the gate is high with respect to the drain, and so the PFET does not conduct, and the LED is dark. When the current through the PTC exceeds the trip current, the resistance increases dramatically (and with it, the voltage drop across the PTC). Then the pull down brings the gate voltage closer to the drain voltage, and the PFET conducts, lighting up the LED.
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Because I wanted to be able to handle large voltages (~40V, max), I used 3x 10k resistors in parallel, for a poor man's 3k3 high(er) power resistor, to avoid exceeding the current limit of the LED. I was worried that they would be too much to light up well when using the 5V from the USB connector, but I tried it out, and though dim, it is visible.
Now I have something I can use for in-line current measurements for USB-powered projects (or chargers, or whatever), and I can limit the current to less than the 500mA max provided by the USB spec (yes, I know that high power devices are supposed to negotiate high power usage with the host...). I hope it proves useful in isolating the short in my other project, we'll see.
I have been putting together my free Programmable Load PCB, based on this design: http://dangerousprototypes.com/docs/Oth ... Dummy_Load, and this forum thread: viewtopic.php?f=19&t=3532 [attachment=2] I failed to add some of the parts to my latest order, so I had to make do. I used an 0.1ohm 1% 3W power resistor for R4, and an MTP3055 for the power MOSFET. Here's my makeshift PTC resettable fuse. It can only handle 250mA, so I want to retry and upgrade it sometime. The current sense resistor and the MOSFET should easily be able to handle up to 3A.[attachment=1] Here's a hack to attach a switch I had, which fit okay, though it hangs off the edge of the board. You can also see the power jack, which works, but the programming header is in the way, I'll have to adjust it.[attachment=0]
That forum thread shifted to another topic, so I made a new one here, for my questions. I think I get the general theory of the design, but I am not sure on a few of the resistors that were not set up in the BOM. Can anyone explain what purposes R2,R3,R5,R6, and R7 serve, or what values I should use? I'm kind of a greenhorn with this kind of analog stuff, know that there's no current that flows from the MOSFET base to the drain, so what does R3 do? Does it introduce a voltage drop to reduce the voltage at the MOSFET's base? I know R6 sets the gain for the opamp providing the voltage drop over the current sense resistor to the PIC, but what kind of gain should I use? Do R2 and R5 set some kind of scaling? Any feedback would be helpful.
Finally, does anyone have an example firmware for this project? I was going to try and cook something up based on the LCD backpack firmware, if I can't find anything else, but a better starting point would be great...
I just wrote up an instructable (here: http://www.instructables.com/id/Paneliz ... ree-Light/) about how you can easily panelize PCBs for SeeedStudio's Fusion PCB service. I thought it might be of some interest here, especially considering that they are currently offering 10 count 10cm x 10cm PCBs for the same price as 10 count 10cm x 5cm PCBs.
It requires a minor patch to gerbmerge, but after that, it works like a charm.
I made this a while ago, but just busted it out, and hadn't yet posted up a photo of it. I added the optional 20MHz xtal to the back, to use as the global clock. Also, I only had a 6mm switch, but it seemed to (kind-of) fit, and it works okay.
I love these CPLD breakouts, they're so simple (hardly any support circuitry!), but they can still do a lot of interesting things.
I just assembled the Part Ninja PCB I received. I didn't have the 1.2V reference on hand, so I left it unpopulated. It's on order, but there's no hurry, since the firmware isn't really developed. [attachment=0] I found the main development thread: viewtopic.php?f=19&t=3260, but its super long. Is there any summary of the design or development work? Maybe I could find something to contribute, if I could get a sense of where things are...
It started out as this project I mentioned a while back (viewtopic.php?f=56&t=2524) of having two single-sided development boards (one for ATmega328, the other for ATmega644) back to back on the same PCB, but that goal turned out to be too ambitious. I ended up with two separate boards, for the most part, single sided (the easier to make at home), with some extra features.
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I have a number of other Arduino-compatible development boards (BoArduino, Seeeduino, Ardweeny, to name a few), but I use these for project development, and have been unable to bring myself to commit them to a project. The support circuit for the Arduino-compatible AVR is not too complex, but I didn't relish the thought of re-implementing it time and time again on perfboard. So I made these breakout project boards that would have most of the stuff I might want (power supply, FTDI cable connector, SMD breakout and prototyping areas) that I could commit to simple projects without wanting to remove the controller later when I had another idea to prototype.
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Like the writeup I mentioned, I have two versions, one for ATmega328 (which would also work with the ATmega8 or ATmega168, I would suppose) and one for ATmega644 (which I suppose would also work for the ATmega1284). There are more details, including the BOM and downloads, here: http://http://spaceagerobotics.com/blog/projects/sarduino/. Once the boards arrived, I assembled them for testing, programming the bootloaders with my trusty BusPirate FTDI:
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I have already constructed a long list of improvements for future versions, if there are any. I have some extra PCBs, so let me know if you want one, $5 shipped anywhere.
I put together my UBW32 free (guest) PCB the other day. Here's a pic: [attachment=0]
I didn't have the SOT-223 LM317, so I used a fixed 3v3 1117 instead. Since it doesn't require resistors to set the output voltage, I left the feedback one off and used a 603 zerohm jumper to short the GND pin to GND. Also, I didn't want to buy the tiny power selector switch, so I just soldered a 1206 zerohm jumper to permanently select USB power. That meant I could leave off the 5V regulator / external power subcircuit.
The 0.4mm pitch PIC was really daunting, but I used Arup's "use the solder already on the pads" trick, and it looks like a good connection all around. I'm used to having more space for the 603s, maybe these pads are tinier than the ones from DP that I'm used to doing, but there was hardly any extra room. I used my new soldering station, but the chisel tip I have is way too big, I definitely need to get a smaller one.
I haven't had a moment to try it out yet (my MPLAB PC is down :-[ ), so maybe I'll post an update when I get it up and running again.
I've been looking for a cheap hot air rework station for some time, and found this bad boy on Amazon ($85 shipped) a few weeks ago: [attachment=2] http://www.amazon.com/gp/product/B004ZB9D4O
It's a "Kendal" brand, whatever that means, and the ever popular 852D+ model number, like so many cheap knockoffs of its ilk. It arrived the other day, and my first thought was, "don't turn it on, take it apart!", so I did. Here are some shots:
First, everything laid out on the table. [attachment=1]
I tried taking the cover off, and the production quality showed through immediately, for there was a stripped screw I could not remove, and I had to kind of shove the cover out of the way to get at the insides. [attachment=0]
I just received two ITead PCB orders, and I chose the "Open PCB" option, where for $0.10 each, they will make two other copies of your PCB for a pool of open PCBs, and then send you two other PCBs from the pool.
One of the boards appears to be the same TFT Digital Picture Frame board that arhi received: viewtopic.php?f=2&t=3369
Most of the boards naturally (indeed, like my own) bump up against the 5x5 or 5x10 size limit of the service
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The first one appears to be a CAT4101 Triple Driver, from here: http://code.google.com/p/hpled/wiki/PageName?tm=6 The board is quite old (March, 2010), but there don't appear to be any new revisions on the site.
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The second one appears to be some kind of LCD driver. I haven't been able to find anything out about it, and am waiting for a response from the email I sent.
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The third one is produced by bitlair.nl, and appears to be some kind of RGB driver: https://bitlair.nl/archives/200. It uses 3 LM317s, one per channel, and it has some kind of MCU (I'm guessing AVR, like an ATmega8/168/328, from the pinout). It has lots of interesting art on the PCB, which is nice. But I haven't found any writeup on the board, just waiting for a response to my inquiry.
I participated in the Open PCB program for the chance (however minuscule) to get something useful or interesting, but I don't think I have any immediate use for any of these boards, and may be willing to offer to post them to anyone who thinks they can use them (or put them in the free PCB drawer, Ian?).
I will post about the boards I ordered once I have a chance to test them out.
I finally started assembling my free PICqueno32 DIP PCB. I didn't have any 30-pin headers, but I did have some 32-pin double row headers, so I used those. So I didn't have a row of useless headers in the way, and so I didn't have to try and trim them, I bend the unused pins over and soldered them in line, so now I have 32 pairs of connected pins, with one header row to solder through the board: [attachment=2] [attachment=1]
I don't have any FTDI chips, so I'm going to use my FTDI cable to program sketches to it.
I successfully programmed the bootloader using my ICD3.
