What have I done?

Well, I’ve spent the last few days and a good deal of cash on designing and laying out a new STM32F405 based NETMF board for an industrial control project I’m working on.

Just ordered all the parts, the PCBs (Hope DF Robot can make sense of them) and a shiny new IR reflow oven from eBay. It has cost a small fortune to get started, but the experience and functionality the board will offer, not the mention to savings on the next one will make the effort worth while. Thanks to my very understanding and patient mentor @ Justin, for his endless enthusiasm and insight; wouldn’t have wanted to do it without him.

Should have the boards back in 5 days (plus shipping) and then the fun will really start. Getting the firmware onto the STM, programming the BLE, playing with I2C LCB displays and EEPROM devices, oh and then there’s the actual industrial stuff to do as well. Added to all that, a simple WP8 or WinRT app to interface to the BLE and we’ll be good to go.

I’ll keep you posted on my progress.

Wish me luck. :open_mouth:


Nice work Jason. Looks like you get to play with Altium Designer too?

Did you opt for a 2 or 4 layer board?

I am working on a NETMF design myself based on the same processor and going for 4 layer. Our friendly neighbourhood NETMF Guru Justin also suggested I go with NETMF after he explained how easy it was to get NETMF on the processor.

There are 2 boards in my design. The second one will be 2 layer as it only handles relays and a small power supply. I chose 4 for the CPU board as it is easier to get a cleaner EMC design as this will be installed on a truck. Last time I did a 2 layer board and it was noisy on the radio. Changed that same design and layout to use 4 layer and the noise went away. :slight_smile:


@ Dave McLaughlin - Just a 2-layer to cut my teeth on. Routed by hand too :whistle:

As I get more comfortable I can see a need to go to 4-layers and I really want to get either some WiFi or Ethernet onto a design soon too.

I agree that 4 layers is often better EMC-wise. That top power plane is pretty badly chopped up and doesn’t look to be particularly well stitched to anything. Everyone’s a critic I suppose :wink:

Looks good though. Fingers crossed it will ‘just work’.

You know you’ve spend too long in one programme when you start to use it’s shortcut keys in another. :wall:

It’s a shame not everything shows full zoom with a V - F shortcut!

@ hagster - For my first design I didn’t really want the additional cost. Assuming that I got everything right and there is nothing missing :-[ or no additional functionality I decide I want :think: to incorporate then migrating to a multi-layer would be the way I’d go too.

The prices from DF Robot are amazing, even for a 4-layer, but I can get this one wrong a time or two and still be less than the cost of a 4.

Let’s hope the thing works; I’ll worry about the rest next time.

I’ve not used the auto router on Altium since the Protel 99 days. It makes such a mess that it is not worth it. What I normally do is place all the parts, run the auto router to check it can do the complete board, which sort of gives you an idea of the layout being good and then un-route and do it manually. :slight_smile:

I’ve found that the latest tools make manual routing a pleasure these days.

Ha ha. Been there, done that and have the medal to prove it. :slight_smile:

It gets worse when programming. Wish they would all use the same F keys for the place breakpoint, start, single step etc. Goodness knows how many times I’ve done a rebuild when all wanted to do was single step the code. :slight_smile:

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Well, DHL have just delivered my new PCBs from DF Robot. Now all I have to do is find enough to keep me busy until the end of the day so I can go home and get one built. I’ll post my progress (with pics) later.


It took a while to get organised, but they’re finally in the reflow cooking. I’ve built two, one without BLE. I’ve got 6 minutes to wait and then begin the job of checking for shorts and solder bridges and then PROGRAMMING… Not sure if I’m 98% scared, 2% excited, or 2% scared, 98% excited. I guess I’ll know soon enough.

Here’s some progress shots to whet your appetites’…

Oh, and 0603 is SMALL!!!


Cool, envy, green, but still cool … 8)

Progress!! Looking forward to seeing it in action!

What type of solder are you using? Leaded/Unleaded? Compound?

@ mhectorgato - It’s

MULTICORE (SOLDER) - 2006905-M - SOLDER PASTE, 62/36/2, 179 DEG


Nice work! And 0603 tests your eye sight :slight_smile:

I bought myself tweezers and magnifiers to work on those little beauties.

Tweezers I have, but the magnifier I have at home is not strong enough. Think I need an upgrade.

Well, they cooked after a couple of tries. The heat doesn’t seem completely even in the reflow so some experimentation is required I think.

However, there seems to be a problem that I don’t have the test equipment, patience or eye-sight to deal with tonight. :frowning: I don’t think there can be much of a problem but DfuSe doesn’t see the board. I’ll have a dig around tomorrow and let you all know.

If anyone has experience of troubleshooting this type of stuff I’d welcome your insight or thoughts.

See you tomorrow.

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These work well for me: http://www.pjtool.com/head-magnifying-visor.aspx

I got these as well, but they are useable for me only up close – so I use them for inspection: http://www.ebay.com/itm/20x-Jewelers-Magnifier-Magnifying-Glasses-Eyeglasses-for-Gold-Silver-Jewlery-/360625410545

(not that I’m an expert by any means :wink: )

My first inspection point is the USB socket. Damn hard to see excess solder and bridges under them, so take a GOOD look, even check connectivity with a multimeter if you have access to the pads (mental note: should put test points on the board for that :slight_smile: ). Then I would look at orientation of the processor to make sure I got that right. Then I’d phone Justin to yell at him for leading me astray :slight_smile:

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@ Brett - With a night’s sleep and not quite so much caffeine, I managed to get both boards working. The USB got removed and re-soldered. There were a couple of other shorts that I got rid of too. The boot switch was the wrong way around too. Once those things were all worked out (it took about an hour and some Skyping with @ Justin) they both sprang to life. Got the loader on use DfuSe and then into FEZ Config to get TinyCLR on board.

Finally it was time to write some code.

Well, LEDs flash, I2C to my Midas LCD works as does the 24V switching for some industrial control. :dance:

I’ll add the BLE later and hopefully get that programmed up to. The I2C for the EEPROM needs adding to, but that shouldn’t be too troublesome. :smiley:

Many thanks to all who helped me get this far. You know who you are.


@ Brett - With a night’s sleep and not quite so much caffeine, I managed to get both boards working. [/quote]

Congrats to the proud papa!

Justin is a rather helpful fellow who is generous with his time. :clap:

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