Introducing the ARM PRO MINI board - ARM Made Easy - Page 1
Forum section: electronics / general

author: zapta
author_rank: Super Contributor
timestamp: December 18, 2014, 09:09:14 pm
content: The first version of the ARM PRO MINI documentation is available on githubhttps://github.com/zapta/arm/tree/master/pro-mini(scroll down that page).The ARM PRO MINI is a small ARM M0 OSH board that makes it easy to experiment with the ARM architecture and to incorporate it in your own designs. Installation of the tool chain is a breeze (a single package install), the IDE is feature full (compared to let's say the Arduino IDE), the hello world program compiles works out of the box, the board does not require programmers or adapters whatsoever (it is ready to use out of your reflow toaster oven and can work with a debugger if you happen to have one), Windows, Linux and Mac OSX are supported and of course it comes with non nonsense open source license (cloning and commercial use are ok, sharing and attribution are not required). Life could not be better! Were is the catch you ask? Well, there isn't.I will appreciate any feedback on the documentation and especially on the Getting Started steps and on the board in general. If you have any question or comment please post here or PM me. I may be able to provide a few free boards for people that want to play with it. I do not plan to commercialize it myself.Also, thanks for paulie for suggesting the and and for the EEVblog community for reviewing the design (https://www.eevblog.com/forum/microcontrollers/my-first-armlpc-design-please-critic/)EDIT: adding a picture without the 3D printed case

author: paulie
author_rank: Frequent Contributor
timestamp: December 18, 2014, 09:21:11 pm
content: Thanks again for sending me that prototype. There are literally dozens of ARM boards floating around here now yet that is absolutely my favorite. It's definitely the easiest to program of any ARM too thanks to virtual drive interface. NO drivers or special download software to hassle with. It don't get any easier than drag-n-drop.Thanks for the spare boards too. My chips finally came in and experiments with minimum components showed it can run with very few parts. 4 IIRC. Not counting connectors. I just love this design. No missing pins or other drawbacks like AVR Promini or the Maple ARM boards.

author: LabSpokane
author_rank: Super Contributor
timestamp: December 18, 2014, 10:49:36 pm
content: OK, that is a seriously awesome better mousetrap. But why did you have to show me that *after* I ordered a stack of 328 pro minis from Shenzen?

author: zapta
author_rank: Super Contributor
timestamp: December 20, 2014, 06:03:55 pm
content: Quote from: paulie on December 18, 2014, 09:21:11 pmI just found that it doesn't even need tool-chain installation.Login tohttp://developer.mbed.org(requires free registration), add one of the LPC11U35 platforms to your account and the online IDE will compile and generate a .bin files that you can load directly to the ARM PRO MINI.No programmer/debugger, no USB/serial adapter, no software installation, and it is ready to program and use straight out of your reflow toaster oven. NXP/Arm did a really good job.This is how the online mbed IDE looks in my browser:

author: nctnico
author_rank: Super Contributor
timestamp: December 20, 2014, 06:20:58 pm
content: Thanks for the effortI really hope it helps people to finally leave old relics from the 20th century behind

author: mtdoc
author_rank: Super Contributor
timestamp: December 21, 2014, 01:28:38 am
content: Well done Zapta. That looks very cool!QuoteJust a FWIW:Energiaworks similiarly easily with TI's Tiva C ARM development boards (and MSP 430s). It's basically an Arduino IDE clone that is also cross platform so it's not as full featured as this.

author: zapta
author_rank: Super Contributor
timestamp: December 21, 2014, 04:41:20 am
content: Quote from: mtdoc on December 21, 2014, 01:28:38 amFirst time I hear of it, looks very interesting. IMO simple install of the tool chain and running on multiple OS's are very important for open sources projects. Users often need to make small tweaks (e.g. to the Marlin firmware of my 3D printer) so installation and use should be straight forward and easy to use. This is one of the strongest points of the Arduino IDE.BTW, I added here instructions on how to compile a simple ARM PRO MINI blinky with the mbed online IDE. It's a very nice environment considering that it's browser based. I am yet to figure out how to use the arm_pro_mini_lib with it.https://github.com/zapta/arm/tree/master/pro-mini#compiling-with-the-armmbed-online-ide

author: neslekkim
author_rank: Super Contributor
timestamp: December 21, 2014, 04:44:23 pm
content: Is this board going to be available at Tindie or other places for purchase?

author: zapta
author_rank: Super Contributor
timestamp: December 21, 2014, 05:39:31 pm
content: I don't plan to commercialize it myself but the OSH license is very liberal, even commercialized cloning is ok, share alike and attribution are not requires. I will try to get awareness from a few suppliers but it will be up to them.I have a limited set of populated boards (building them at home with Digikey parts, no magic here) that I can mailed for free to established eevblog users. Send me a .bin file that prints your name and address and I will see what I can do. This will show some level of seriousness on your part. You can find instructions in the getting-started sections in this pagehttps://github.com/zapta/arm/tree/master/pro-mini

author: dansku
author_rank: Regular Contributor
timestamp: January 06, 2015, 07:30:10 pm
content: I'm very excited to build this board.I just received all parts, and now I'm waiting for the PCB to arrive from OSHPark.I will post updates when I get it O0

author: cloudscapes
author_rank: Regular Contributor
timestamp: January 07, 2015, 12:04:29 am
content: is the plastic "shoe" removable? seems like it would use up valuable breadboard space

author: zapta
author_rank: Super Contributor
timestamp: January 07, 2015, 12:43:27 am
content: Quote from: cloudscapes on January 07, 2015, 12:04:29 amYes of course, it's just to protect the PCB when used stand alone.Edit: added this picture to the documentation page

author: cloudscapes
author_rank: Regular Contributor
timestamp: January 08, 2015, 09:37:19 pm
content: excellent, I should have also said it looks good (which it does!). been looking for an excuse to dive into arm/mbed

author: zapta
author_rank: Super Contributor
timestamp: January 09, 2015, 03:57:02 am
content: Quote from: cloudscapes on January 08, 2015, 09:37:19 pmI find the ARM architecture to be easier to use and more straight forward than AVR. Reminds me the difference between the 68000 and 8086 in the old days.

author: paulie
author_rank: Frequent Contributor
timestamp: January 09, 2015, 04:10:58 pm
content: That sounds ridiculous to me. AVR was modeled after the 68xxx/DEC instruction sets and has far simpler yet similarly powerful peripheral register setup. It does occur to me that the C (centipede) Girls may lack accurate perspective on the matter since most of the ugly details are hidden from their delicate sensibilities.I will say this particular board is still my favorite over any of the other ARM or AVR dealies mostly because of that drag-n-drop capability. I don't know why none of the other low cost platforms haven't adopted similar approach. There's something very nice about not needing special download utilities or drivers.

author: LabSpokane
author_rank: Super Contributor
timestamp: January 09, 2015, 04:20:43 pm
content: Quote from: paulie on January 09, 2015, 04:10:58 pmI thought the whole MBED platform was drag&drop? The ST Nucleo definitely is.

author: paulie
author_rank: Frequent Contributor
timestamp: January 09, 2015, 04:45:43 pm
content: I was mostly referring to the "low cost" chips, 1-2 dollar range. Not too sure about all the Nucleos but ones I checked they were using more expensive parts. And I wasn't aware lower cost versions had that capability built in. IIRC only the dev boards were flashed with that capability. I'm not positive though but thought it was kinda like PSOC boards flashed with a serial bootloader but chips from the factory not.Really I would like to see some of the $1 ARMs and AVRs adopt this method of programming. It should be possible seeing how products like AVRASP have USB functionality without built in USB hardware.

author: zapta
author_rank: Super Contributor
timestamp: January 09, 2015, 05:18:29 pm
content: Quote from: paulie on January 09, 2015, 04:10:58 pmI will give you an example, I implemented a simple i/o pin library for both the AVR and ARM. With the ARM things were more intuitive, the port can be refered to using a simple pointeruint8* const pin_gpio_B_;and the pins can be refered to using simple array notationLPC_GPIO->B;https://github.com/zapta/arm/blob/master/pro-mini/lpcxpresso/arm_pro_mini_lib/inc/io_pins.hSame goes for string literals, the flash is mapped to the standard memory space and you don't need special considerations to avoid duplicating the literal also in RAM.This is subjective of course but hopefully it explains my view point.Quote from: paulie on January 09, 2015, 04:10:58 pmYou may like also the ARM MINI NADA (do you like the name?) which is a brutal minimization of ARM PRO MINI. It's still a work in progress but the circuit does work for me.TP11, 12 are free so you can patch them on the board to any additional pins you want to have externally. I think the crystal is required for proper USB operation (is it?), I would love to switch the internal RC oscillator. I reduced the four bypass caps from 0603 to 0402 (same values) and removed the USB data protection diodes and termination resistors (everything works and signals look clean).What do you think? Any suggestion?Schematic herehttps://github.com/zapta/arm/blob/master/pro-nada/eagle/arm-pro-nada_schematic.pdf?raw=true

author: paulie
author_rank: Frequent Contributor
timestamp: January 09, 2015, 05:47:04 pm
content: That does resemble my initial one dollar one minute approach which saved on pins to allow lowest cost possible (thanks again for motivating that whole project). To be honest though I'm more inclined toward making all pins available. IMO a crime to cripple a chip like that. It was also one of my complaints about the original AVR Pro Mini which only have a few missing.A few others complained about my $1 ARM too. So as you might recall l quickly remedied the situation with another iteration with all pins available. The only problem being that enormous 11 cent increase in expense.Personally I have few (no) improvements to suggest for your first board. No way I could have done as good. However if somebody were going to produce "Worlds Smallest ARM" it might be an idea to keep the Nada size but maybe bring all pins out on 1.5mm or 1mm headers. Or just half feedthroughs on the edge like ESP and Bluetooth modules. Whatever we think we can get away with.

author: dansku
author_rank: Regular Contributor
timestamp: January 13, 2015, 03:04:24 am
content: Today I receiver the PCBs for the ARM PRO MINI.Here are some pics:I started soldering the parts, but fucked up when I had to solder the µC..I think there was some short circuit on the pins and kaput...Good think OSH Park always send three boards. Now I will buy some of the componentes again fro DigiKey and hope I do it better next time.Any advices on soldering the µC?

author: zapta
author_rank: Super Contributor
timestamp: January 13, 2015, 04:27:33 am
content: Hi Daniel, you can mail it to me and I will try to fix it. I built this weekend one board from OSHPark and it worked (before I was using Elecrow).Were did you get a short? I have good experience with Oshpark (from previous orders) so possibly it's just a soldering short.

author: dansku
author_rank: Regular Contributor
timestamp: January 13, 2015, 04:52:11 am
content: Quote from: zapta on January 13, 2015, 04:27:33 amIt's a soldering short for sure! I did a bad job soldering the µC, those pins are not easy to solder. I tried to turn the board one, and there was a short, I am not sure if all components are still working.How much work would it be for you to solder one board? I could send you one of the PCBs from OSH Park and buy the components and send to you. Or I will just buy the parts and try a second round.

author: zapta
author_rank: Super Contributor
timestamp: January 13, 2015, 05:13:31 am
content: Quote from: dansku on January 13, 2015, 04:52:11 amI enjoy soldering so it will not be a problem. ;-)You can send me what you have and I can try fixing it. I solder my boards with a metal stencil I got from elecrow. I never tried soldering 0402 and 0.5mm pitch ICS without a stencil but should give it a try. A good magnifier is useful for sure.One trick I use for fine soldering is plenty of tacky flux.

author: dansku
author_rank: Regular Contributor
timestamp: January 13, 2015, 05:14:50 am
content: Awesome! I will ship the current board to you, and you can take a look then!!Thank you very much!!!I will get your address on Private Messaging.

author: dansku
author_rank: Regular Contributor
timestamp: January 13, 2015, 05:17:40 am
content: How do you get the metal stencil? Do they provide it when you make a pcb with them?!

author: zapta
author_rank: Super Contributor
timestamp: January 13, 2015, 08:41:26 am
content: Quote from: dansku on January 13, 2015, 05:17:40 amIt's an extra thing that you order and they make it from the gerber files. You can get plastic ones for chip from oshstencils.com (not related to oshpark) but am not sure if the resolution is good enough for 0.5mm pitch. Electrow and others such as dirty pcbs make them from metal (laser cut) and they have better resolution.

author: paulie
author_rank: Frequent Contributor
timestamp: January 13, 2015, 12:08:50 pm
content: I built several of zaptas boards now and was lucky to have no failures. No stencil. The way I do it is tack the chip down with tiny speck of solder on two corners then add a big glob on all the pins. Heat each side and BANG the excess solder off by rapping the board edge on a hard surface. Like zapta says lots of resin helps then you can clean it off with isopropanol. This method has worked for literally hundreds of SMD chips and no failures yet.All but one of my boards are only partially populated but still work 100%. The diagram for the "nada" has all the components needed which is much less than the full size version and will increase chances of success. After it is working you can always add the rest later .ps. Another suggestion is to order more than one chip at a time. Not only do they cost less but you will have backups. I am the worlds cheapest man but IMO worth a few extra bucks for such a nice project.

author: dansku
author_rank: Regular Contributor
timestamp: January 13, 2015, 04:05:36 pm
content: Yeah, after doing some research, I found out that there are two things that would make the work SOOO much easier and faster.1st - As described by zapta, the stencil/metal mask.2nd - reflow oven.The only problem is that I'm moving to Australia for a year in 3 weeks, so I won't build one DIY reflow oven now, maybe when I come back!How shitty would it be to try to reflow on a working small electric oven?

author: uChip
author_rank: Contributor
timestamp: January 13, 2015, 04:35:12 pm
content: QuoteAccording to Nate, their founder, SparkFun ran their business for a time using a hotplate for reflow. You might try that method. Or a toaster oven is not that different so I would think that would work as well.Zapta, this is an awesome design. Thanks for publishing! Have you approached SparkFun or anyone to make these available commercially? Seems like a good opportunity all round since not everyone is comfortable with SMT work.- Chip

author: Mechatrommer
author_rank: Super Contributor
timestamp: January 14, 2015, 12:00:31 am
content: Quote from: zapta on December 21, 2014, 04:41:20 amno! browser based is not nice for oldtimer like us. give us standalone based and we may consider programming with... and for us who have other things to do, we just prefer to buy it from you (if the price is reasonable) we dont have time to mess redesigning the board and ordering from pcb fab house and plethora of components suppliers. nice effort though on the hw side. after you settle the sw standalone ide side, you may expand your idea to larger pin count such as arduino mega, because mini is too limited for some larger application such as full color tft with other stuffs to do.edit: i noticed the lpcxpresso now, downloading...

author: zapta
author_rank: Super Contributor
timestamp: January 14, 2015, 02:51:37 am
content: Quote from: Mechatrommer on January 14, 2015, 12:00:31 amI may be able to supply the boards in small quantities for direct cost (or for free if it's only a few). I will try to get the attentions of vendors such as Sparkfun and Tindie. I have a day job that pays the bills so my goal here is to make available an ARM board with great experience out of the box (I hate 'tool chains') and that can be used as starting point for custom PCB designs.If you want one for free, send me a .bin file with the hello_world.cpp program modified to print your name and mailing address. (limited time and quantity offer).

author: zapta
author_rank: Super Contributor
timestamp: January 14, 2015, 08:54:42 am
content: I updated the u8g lib driver to work with the ARM PRO MINI. It can now be hooked to graphical displays via SPI. Here is my test unit with a 1.3" 128x64 pixel OLED, updated at 20 fps (frame update time is 8ms so it can go 100fps).Sample program is herehttps://github.com/zapta/arm/blob/master/pro-mini/lpcxpresso/u8g_example/src/u8g_example.cppDriver is herehttps://github.com/zapta/arm/blob/master/pro-mini/lpcxpresso/u8g_lib/src/u8g_arm_pro_mini.cpp

author: dansku
author_rank: Regular Contributor
timestamp: January 14, 2015, 03:03:01 pm
content: Quote from: zapta on January 14, 2015, 08:54:42 amLooking great!!

author: dansku
author_rank: Regular Contributor
timestamp: January 14, 2015, 03:31:49 pm
content: I was analyzing the arm pro mini schematics, and I have two simple questions.What does theOptional AandOptional Bdoes on the circuit?Thanks

author: zapta
author_rank: Super Contributor
timestamp: January 14, 2015, 10:28:01 pm
content: Quote from: dansku on January 14, 2015, 03:31:49 pmOptional A allows the MCU to control its USB enumeration by the host. The host will consider the board to exist only when the 1.5k resistor is pulled up. It is useful for example when switching from serial to ISP mode and vise versa, or if your USB initialization code is too slow after the reset (typically not a problem).Without A the device exists whenever it is plugged in. To switch between serial and ISP you need to replug the board. This is exactly what I am doing with the ARM PRO NADA board (which is a very strip down version of the ARM PRO MINI).Optinal B includes two functions, ESD protection and impedance matching. I removed both in the Nada board and everything still seems to function.BTW, the USB connector itself is also optional. For example if you don't use USB and just want occasional firmware upgrade you can have a header or exposed pads as people do with ICSP.BTW, I am not a USB expert so other may provide more details.

author: dansku
author_rank: Regular Contributor
timestamp: January 14, 2015, 10:43:44 pm
content: Quote from: zapta on January 14, 2015, 10:28:01 pmAwesome, thank you for the info!!Even that you can program the board using a ICSP, I think that the USB makes it even easier for people to start programing using the board!

author: zapta
author_rank: Super Contributor
timestamp: January 17, 2015, 05:06:01 am
content: Quote from: dansku on January 13, 2015, 05:14:50 amHi dansku, the board arrived, got fixed and will hopefully go out with tomorrow's mail.The main problem was the soldering of the USB connector. It had shorts and one pin didn't have solder. I noticed solder paste that didn't melt so I reflew it again and this fixed the shorts. Also, the board has some white crust, probably from the flux, that I never seen before and it didn't come off easily with IPA. I wonder what solder paste you use.The 0.5mm QFN MCU was soldered OK. It's interesting that soldering the micro USB connector is more challenging than the QFN. This is also my experience. Never had a problem with the QFN.I think you need to refine your reflowing process. I am not an expert but others may provide more information.I have used elecrow 5mil metal stencils but oshstencils says that their plastic stencils can do 0.5mm pitch. I have on order two stencils 3mil and 5mil so will see how this will go. The plastic stencils are cheaper and arrives in the US in few days. Will see how it will go. Placing the paste with toothpick or syringe doesn't work well for me, stencils do.

author: dansku
author_rank: Regular Contributor
timestamp: January 17, 2015, 02:41:02 pm
content: Quote from: zapta on January 17, 2015, 05:06:01 amThank you for the help!I tough that the problem was in the QFN soldering.I know my soldering process was ridiculous, I only have the solder paste but no stencil, so what I was doing is using a toothpick to place the paste on the soldering and using a soldering iron to finish it... You saw the result.I have the stencils coming, hope everything works better the second time. What do you use to remove flux after soldering? I had a lot of flux left on the board, which is gross and makes it look bad!

author: zapta
author_rank: Super Contributor
timestamp: January 17, 2015, 04:30:48 pm
content: I am using this solder paste and it comes off with IPA. They also have a T5 type with finer solder balls but the T3 works good enough. Syringes are wasteful since you cannot return the leftover to the container so I use jars. For cleaning us use foam swabs (each lasts for many boards) and and a brush which I trim short to be stiffer (search ebay for: acid flux brush).Never seen that kind of crust earlier. Must be from the the solder paste you are using. Try to search these forums for solder paste recommendation. May be a good topic for a new thread, good combinations of solder paste and matching cleaning chemicals and techniques. For example, I have a ultra sound cleaner, would be nice to just throw the boards in and let it do its magic. Never tried, not sure what non flammable liquid to use. I am not an expert.http://www.digikey.com/product-search/en?x=0&y=0&lang=en&site=us&keywords=SMD291AX250T3http://www.ebay.com/itm/100-PCS-Small-Foam-Tipped-Cleaning-Swabs-swab-for-Inkjet-Printer-Electronics-/290991199907?pt=LH_DefaultDomain_0&hash=item43c06d56a3http://www.ebay.com/itm/12-Disposable-Acid-Brush-also-use-for-Craft-Glue-Epoxy-Paint-Flux-brush-and-more-/201266140243?pt=Model_Kit_US&hash=item2edc659453

author: paulie
author_rank: Frequent Contributor
timestamp: January 17, 2015, 04:51:29 pm
content: IMO it makes little sense to get involved with solder paste and certainly stencils for one or two boards. That does seem to be popular with hobbyists, however saving time, money, and effort are never high on their list. Regular 1% 37/63 wire solder with cheap (but plated tip) pencil iron is the key for those with "git 'er done and git 'er done with least fuss" philosophy.I recall Youtube videos from one or two guys who actually do know how to prototype SMD the easy way. Unfortunately outnumbered 100:1 by the guys who don't. So the current hobby state of events is pretty understandable.

author: zapta
author_rank: Super Contributor
timestamp: January 19, 2015, 09:14:26 pm
content: Here is Hackaday's entry for ARM PRO MINIhttp://hackaday.com/2015/01/19/arm-pro-mini/

author: dansku
author_rank: Regular Contributor
timestamp: January 19, 2015, 09:17:58 pm
content: Quote from: zapta on January 19, 2015, 09:14:26 pmCongrats Zapta!!!

author: Mechanical Menace
author_rank: Super Contributor
timestamp: January 20, 2015, 04:52:17 pm
content: I think I've just found the solution I didn't even know I was looking for. Thanks for the great work zapta.

author: mtdoc
author_rank: Super Contributor
timestamp: January 20, 2015, 04:58:09 pm
content: Quote from: dansku on January 19, 2015, 09:17:58 pmYes. Congrats! Well deserved (even if you are a wacky anti RE, anti EV 'er). This looks like a really good easy ARM solution. It deserves more exposure.

author: zapta
author_rank: Super Contributor
timestamp: January 20, 2015, 05:45:29 pm
content: Quote from: mtdoc on January 20, 2015, 04:58:09 pmThanks mtdoc. Doubly appreciated ;-)The main design goal was to make it simple and effective and a great out of the box experience. The wide selection of ARM devices and the 'tool chains' may be overwhelming. ARM tried to address it with the mbed cloud thing but I don't see it getting much traction in these forums.

author: neslekkim
author_rank: Super Contributor
timestamp: January 20, 2015, 08:59:17 pm
content: Got your board today, pretty thing, and small!, need to figure out how to get it out of the printed enclosure without tearing off the usb connector (only thing to hold on), but very nice kit.

author: zapta
author_rank: Super Contributor
timestamp: January 20, 2015, 10:01:28 pm
content: Quote from: neslekkim on January 20, 2015, 08:59:17 pmThe board is attached with two pieces of double tape, one below the USB connector and the other below the buttons. You can pry them gently. Heating it slightly may also help (don'g heat the PLA case to more than 50C or so).The case acts also as a protector during shipment.Have fun.

author: neslekkim
author_rank: Super Contributor
timestamp: January 20, 2015, 10:19:52 pm
content: Ah, super!, I thought it was the case that very snug fit, but it was only the tape that was strong, nice!What kind of tape did you use?, this was very much better tapes than the ones I have used before?

author: zapta
author_rank: Super Contributor
timestamp: January 21, 2015, 12:20:15 am
content: Quote from: neslekkim on January 20, 2015, 10:19:52 pm3M Outdoor tapehttp://amzn.com/B00004Z4BV. I use it a lot.Edit: sorry for the oversize image. This is what I found on Amazon.

author: neslekkim
author_rank: Super Contributor
timestamp: January 21, 2015, 06:54:07 am
content: Quote from: zapta on January 21, 2015, 12:20:15 amGreat, thanks!

author: dansku
author_rank: Regular Contributor
timestamp: January 22, 2015, 02:22:19 am
content: Thanks Zapta for fixing my noob soldering mistakes!!I'm just having few problems with the board that maybe you guys could help me.I uploaded all examples with no problem, slow blink, fast blink, then I also compiled some code in the MBED IDE.But after I built a code with only 10ms of delay between blinks (the delay shouldn't be a problem), now I can't get the board back to USB Mode. Also when I plug the board the green (USB) led doesn't turn on anymore.Could it be a usb soldering problem?Thanks

author: zapta
author_rank: Super Contributor
timestamp: January 22, 2015, 05:39:54 am
content: Is it possible that it's just an hardware problem? Some short, broken connection, etc?Can you send me that bad binary, I will try to reproduce it here.

author: dansku
author_rank: Regular Contributor
timestamp: January 22, 2015, 02:52:49 pm
content: Quote from: zapta on January 22, 2015, 05:39:54 amThis is the file that I uploaded:http://cl.ly/2p0m0P1a381BMaybe I broken connection on the usb plug?Let me know if yours worked fine!Thanks!

author: zapta
author_rank: Super Contributor
timestamp: January 22, 2015, 05:47:22 pm
content: Quote from: dansku on January 22, 2015, 02:52:49 pmHi dansku, your mbed file seems to run just fine, except that it generates blinking at 50hz (too fast). Also, I don't have a problem going back to ISP mode.You can observe the blinking with an osciloscope or a voltmeter (half voltage on the LED output). If you can't get into ISP mode it's probably some short or connection issue. I have a chopped micro USB cable that I use to test the USB connectivity (just chop the computer side connector and expose the wires).I am getting more boards next week. Will be able to send you one for comparison if it will help.

author: dansku
author_rank: Regular Contributor
timestamp: January 22, 2015, 05:51:52 pm
content: Quote from: zapta on January 22, 2015, 05:47:22 pmYes, It may be some problem with the USB connector. I would love the board to make more tests and projects!I will do some more testing later, I let you know how it goes! Thanks for the help!

author: zapta
author_rank: Super Contributor
timestamp: January 22, 2015, 06:07:26 pm
content: Quote from: dansku on January 22, 2015, 05:51:52 pmI am playing now with a 1.3" SPI OLED display attached to the ARM PRO MINI. The u8g graphics library is easy to use, it's fun to see the things moving on the screen, and everything including the USB serial stack, graphics library and printf library takes ~10k so plenty of room for application code. Life is good.

author: LabSpokane
author_rank: Super Contributor
timestamp: January 22, 2015, 06:28:02 pm
content: Quote from: zapta on January 22, 2015, 06:07:26 pmGot a good source to share for the OLED?

author: zapta
author_rank: Super Contributor
timestamp: January 22, 2015, 06:48:22 pm
content: Quote from: LabSpokane on January 22, 2015, 06:28:02 pmThe original source is Heltec in chinahttp://heltec.diytrade.com/sdp/2044581/4/pl-6785993/0/Product_Catalog.html. For single units ebay is probably your best choice. The only problem is that they have several variations with no clear model numbers.The ones I am using are* 1.3", 128 x 64.* SPI (faster than I2C)* Heltec 'old style' (they have the pins, GND, VCC, SCL, SDA, RST, D/C, CS is permanently selected, and they don't have onboard 3.3V LDO)* white (they have a SSD1306 controller, the blue ones have SH1106).This one on ebay looks like the ones I am using:http://www.ebay.com/itm/1-3-SPI-Serial-128X64-OLED-LCD-LED-Display-Module-3-5v-White-for-Arduino-/261402217702?pt=LH_DefaultDomain_0&hash=item3cdcc94ce6I had in the past ebay sellers advertising it and shipping a different one (same value, they don't understand the difference). I think that as long as you get a 1.3" SPI with SSD1306 (preferred) or SH1106 (requires minor patch in u8glib) you should be fine with some tweaking. The u8glib maintainer is very responsive.If you want a consistent source of such displays, talk directly to Heltec. They are responsive and will ship also small quantities.

author: Jaros
author_rank: Newbie
timestamp: January 22, 2015, 08:04:13 pm
content: Quote from: zapta on January 22, 2015, 06:48:22 pmMay I ask owners of this display, what is the real mA consumption. Does it depend on how many "tiny LEDs" is on?Is it possible to take a picture in direct sun, to see how good visibility is of these displays in daylight.I purchased Sharp MemoryLCD to play with, but they are "expensive"and not sure yet if I want to go with this in my project.and big Thank You to Zapta for sending me one of his arminis.RegardsJarek

author: dansku
author_rank: Regular Contributor
timestamp: January 22, 2015, 10:58:05 pm
content: Quote from: dansku on January 22, 2015, 05:51:52 pmI made a bunch of tests on the board, checked connections, short-circuits. Everything seems to be working fine.The green LED is connected to PIN 02, which is the IO from the µC and apparently is not turning "HIGH", or "LOW". I guess it should be turning LOW because the cathode of the LED is connected.The problem could be with the µC maybe?I will later on destroy a USB cable and see if it could be a problem with the connector!

author: zapta
author_rank: Super Contributor
timestamp: January 23, 2015, 12:22:47 am
content: I would try this1. (I presume that blinking mbed program is still running on your board). Reset the board and observe the voltage at the red led output pio0_7. If it has 50 hz square wave the program is running and the clock and the MCU are alive. (if you don't have an osciloscope, measure the dc voltage, it should be half of 3.3v).2. Measure the voltage on the MCU PIO0_1 and see that the voltage changes between 0 and 3.3v when you press on the ISP button. This is required to enable the ISP mode.3. Verify that PIO0_3 input of the MCU has 3.3V. This is required to enable the USB ISP mode.4. Use a chopped USB cable to test the usb data path from the cable to the MCU (via the 33Ohm resistors). Make sure there are no shorts.The connector on your board felt notchy when I inserted the cable. I assumed it got extra flux or solder paste, but it did work.Let see if this will help.If anybody is interested, schematic here.https://github.com/zapta/arm/blob/master/pro-mini/eagle/arm-pro-mini-schematic.pdf?raw=true

author: dansku
author_rank: Regular Contributor
timestamp: January 23, 2015, 02:04:26 am
content: 1 - pio_07 -> TP3 = 1.6V => OK2 - pio_01 -> TIP17 => 3.3V, doesn't change when pressed the ISP Button3 - pio_03 -> TIP25 =~ 4.8V, that doesn't sound good!!Somehow something got shorted and the µC ist kaput. But it's funny that the it's working and blinking. (why didn't I used such a fast speed)

author: zapta
author_rank: Super Contributor
timestamp: January 23, 2015, 02:11:57 am
content: 2. Pressing the ISP button need to short this to ground so check connectivity. (Verify the pin number in the schema, maybe I gave you the wrong pin number.3. Ideally it should have a voltage divider, currently it has a current limiting resistor. Will revisit it. Also will let you know my reading later at home.#2 above seems to be the problem.

author: dansku
author_rank: Regular Contributor
timestamp: January 23, 2015, 02:46:48 am
content: Perfect!! The problem was with that button!! I kinda broke it, but anyway, by shorting that button it entered in USB mode and now it's working. Just need to solder a new one!!Perfect, thank you very much for the help!!Working like a charm now!!I know it's dirty and ugly, but works and will stay like this until I order new parts O0

author: zapta
author_rank: Super Contributor
timestamp: January 23, 2015, 03:13:48 am
content: Awesome!The board you sent me arrived with the two buttons dead, no tactile feel, probably from the post office sorting machine, so I replaced them. Maybe there is also a damaged trace in that area.Have fun.

author: zapta
author_rank: Super Contributor
timestamp: January 23, 2015, 04:46:41 am
content: Quote from: Jaros on January 22, 2015, 08:04:13 pmMine takes 23ma to 45ma depending on the number of pixels turned on.It's very visible indoor, even with direct light, will try to test it this weekend outdoor in the sun (it's winter here though). For outdoor application a reflective display may be a better choice.

author: Jaros
author_rank: Newbie
timestamp: January 23, 2015, 05:32:47 am
content: Quote from: zapta on January 23, 2015, 04:46:41 amappreciate Your time on this. It is too much, for solar panel/battery supported design.and aboutQuoteI purchased one time 1000pieces very cheap tactile switches form China seller. It said ROHS compliant, but first batch under reflow oven melted in half. Some of them still had a tactile switch look, but there was no tactile feel at all.I had to buy again, twice more expensive.RegardsJarek

author: zapta
author_rank: Super Contributor
timestamp: January 23, 2015, 05:40:47 am
content: Quote from: Jaros on January 23, 2015, 05:32:47 amI am using these ones myselfhttp://www.digikey.com/short/7mvrq9. Probably can cut cost by replacing USB connector, switches, crystal, etc. Can also remove some components such as the diodes (running USB only), the USB protection diodes (it works without them, no problem so far), the LEDs, etc. Not sure how much the MCU cost itself can go down LPC11U35FHI33/501I am building in small quantities so didn't investment too much in cost reduction but there are a few low hanging fruits.

author: dansku
author_rank: Regular Contributor
timestamp: January 27, 2015, 08:06:34 pm
content: Just made a super short "Hello World" tutorial for the Arm Pro Mini...Hope it helps anyone

author: zapta
author_rank: Super Contributor
timestamp: January 27, 2015, 09:44:55 pm
content: Quote from: dansku on January 27, 2015, 08:06:34 pmGreat! Looks very easy ;-)

author: dansku
author_rank: Regular Contributor
timestamp: January 30, 2015, 02:01:41 am
content: Just received a PCB that I made based on the Arm Pro Mini, I called it Ares I.I am still using the Reset/ISP switches. It is almost the same design. I removed the Led on Pin0_7, added all the pin numbers and kept the debugging, though I am planning on removing in on future releases.It was a fun design, I learned a lot creating the board and understanding the ArmProMini design, thank you Zapta for all the tips and useful information!!

author: zapta
author_rank: Super Contributor
timestamp: January 30, 2015, 04:57:25 am
content: Looks very nice. I like the clear pin numbers marking.

author: zapta
author_rank: Super Contributor
timestamp: February 01, 2015, 07:37:13 am
content: The ARM PRO MINI now has a little friend, the ARM PRO TINY. It's a bare bone version of ARM PRO MINI that is still software compatible and has the virtual disk USB/ISP.Diagramhttps://github.com/zapta/arm/blob/master/pro-tiny/eagle/arm-pro-tiny-schematic.pdf?raw=true

author: nctnico
author_rank: Super Contributor
timestamp: February 01, 2015, 10:55:20 am
content: I looked at the schematics. I wish you put multiple processor pins on one PCB pin so you can use more peripherals.

author: zapta
author_rank: Super Contributor
timestamp: February 01, 2015, 11:56:07 am
content: Quote from: nctnico on February 01, 2015, 10:55:20 amThat's a very interesting idea.

author: donotdespisethesnake
author_rank: Super Contributor
timestamp: February 02, 2015, 09:41:26 pm
content: @zapta : would it be useful to be able to compile using the Arduino IDE? Or do you think that is not necessary / a diversion ?Note, I am not suggesting providing a Wiring API - although that might be interesting as well.

author: zapta
author_rank: Super Contributor
timestamp: February 02, 2015, 10:32:54 pm
content: That's an interesting idea. I am not sure how the Arduino IDE works with ARM MCUS and how open is it. I will add it to my todo list. (the advantage of Eclipse is that it fully featured, completion, refactoring, debugging, etc).

author: zapta
author_rank: Super Contributor
timestamp: February 06, 2015, 04:24:24 pm
content: I did a pass of cost reduction and am waiting now for the PCBs from OSHPARK. Same MCU, size, functionality, pinout and software compatibility. Different layout to improve the access to the ISP and RESET buttons.I used digikey cut tape prices for cost estimation and the component cost, without the optional debugger connector (it's through hole so can be soldered by users that want to use a debugger) are1 unit: $8.73100 units: $5.571000 units: $3.93Schematic and layout are here (this is a temporary branch, will move to main branch once I build and test it).https://github.com/zapta/arm/blob/master/pro-mini/eagle_temp/arm-pro-mini-schematic.pdf?raw=truehttps://github.com/zapta/arm/blob/master/pro-mini/eagle_temp/arm-pro-mini-board.pdf?raw=true

author: dansku
author_rank: Regular Contributor
timestamp: February 06, 2015, 08:26:08 pm
content: Quote from: zapta on February 06, 2015, 04:24:24 pmAre these prices for components only?!I contacted some companies to try a turn-key development and in the end it was kinda expensive.

author: zapta
author_rank: Super Contributor
timestamp: February 06, 2015, 08:44:11 pm
content: Yes, components only, without the optional SWD header. The new BOM is herehttps://github.com/zapta/arm/blob/master/pro-mini/eagle_temp/arm-pro-mini-bom.csvWhat kind of pricing did you get for turnkey?PCB should cost almost nothing, not sure what is the going price of PCB assembly (anybody here knows?).

author: dansku
author_rank: Regular Contributor
timestamp: February 06, 2015, 08:51:46 pm
content: Quote from: zapta on February 06, 2015, 08:44:11 pmIn the end, price for PCB + assembly + Parts was going to be almost $20... which is way too much!I wonder if anyone here have some experience with assembly that could help us.

author: Rasz
author_rank: Super Contributor
timestamp: February 06, 2015, 09:16:33 pm
content: Quote from: dansku on February 06, 2015, 08:51:46 pmgo to ebay, search for super cheap arduidiotino clones, ask seller for version with your chip. Some of them are clone manufactures and will gladly bang out a small batch to test watersor forget about nxp chip, and move over to faster M3 STM32http://www.ebay.com/itm/STM32F103C8T6-ARM-STM32-Minimum-System-Development-Board-Module-For-Arduino-DHUS-/321569700934http://www.ebay.com/itm/Hot-Sold-New-STM32-ARM-Cortex-M3-Leaflabs-Leaf-Maple-Mini-Module-For-Arduino-/311248450407

author: zapta
author_rank: Super Contributor
timestamp: February 06, 2015, 10:00:29 pm
content: Quote from: Rasz on February 06, 2015, 09:16:33 pmInteresting, looking at Digikey prices @1k suggest that that ST MCU is significantly more expensive than the NPX lpc11u35, so there is some Chinese magic involved. It's a different league of low cost manufacturing.http://www.digikey.com/product-detail/en/STM32F103C8T6/497-6063-ND/1646338$3.19 @1k // SThttp://www.digikey.com/product-detail/en/LPC11U35FHI33%2F501,/568-9586-ND/3462839$2.28 @1k // NPX

author: paulie
author_rank: Frequent Contributor
timestamp: February 06, 2015, 10:05:03 pm
content: Quote from: Rasz on February 06, 2015, 09:16:33 pm$4.76 for a board 5x faster than AVR. I even feel like a fool for paying $7 for the same chip on one of those F103 minimum "blue boards" too.As far as Digikey chips prices it's western "more money than brains" syndrome and gullible "you get what you pay for" belief system. Not Chinese or any other kind of magic.

author: donotdespisethesnake
author_rank: Super Contributor
timestamp: February 07, 2015, 11:00:40 am
content: At $5 for a Cortex M3 board (incl shipping), it's impossible to beat. Unless you are building your own for fun, you may as well fill your boots with the cheap Chinese ones. The Maple Mini is based on an Open Source design, and can also be used with Arduino IDE FWIW.Of course both boards can be used with IDE/compiler of your choosing, the generic STM32 boards make this slightly easier with JTAG/SWD header. I never did find a schematic for the generic ones, but there is hardly anything to it.The price differential between M0 and M3 is so small it's hardly worth using M0, unless you are planning large commercial production. The prices on some M4's are so cheap, I'm even thinking of skipping M3 and using M4 as entry level. With so much competition in the market, I can only see prices going down.The minor downsides to STM32 are lack of free IDE from ST (I believe they are working on one?), and their chips don't have "drag and drop" USB MSC programming, although they do have various serial bootloaders, or USB DFU. Nothing that is a show stopper.

author: zapta
author_rank: Super Contributor
timestamp: February 07, 2015, 12:14:28 pm
content: Quote from: donotdespisethesnake on February 07, 2015, 11:00:40 amThe tool chain was the main reason I switched away from ST (it was my first choice). I looked for a free single package install IDE that runs on all three major OSs. The drag and drop ISP was a very nice bonus. I also wanted a small footprint MCU to fit in small designs, hence the 5mm package.As for price, the goal of this board is to be a good starting point for own custom PCB designs (as I did with the Arduino pro mini) so the cost of the Chinese prototyping boards doesn't matter that much, but I understand your point.My first custom PCB based on this design will be a small IOT device.

author: Xenon Photon
author_rank: Unknown
timestamp: April 20, 2015, 08:39:32 pm
content: First I'd like to thank Zapta a lot for sending me this amazing little boardFor the windows platform USB/serial it was not included in the guide and I found it was very easy, here is the steps:1.Load and run a hello world image file as described above. Make sure the red LED blinks.2.Identify the serial port on your computer: Open device manger, under "Ports(COM & LPT)" search for "LPC USB VCom Port (COMx)" where x is the com port number.3.Use a terminal emulator to print the text received on the serial port you identified above: Download any terminal emulator, for example Tera Termhttp://en.sourceforge.jp/projects/ttssh2/releases/. Select the com port of your device and click OK.Windows will install the required drive automatically via the internet. if the device was not recognized then download the driver from here:http://www.lpcware.com/content/nxpfile/lpcxpresso-link2-usb-driver-package

author: zapta
author_rank: Super Contributor
timestamp: April 20, 2015, 09:23:31 pm
content: Thanks Xenon, I will add it to the doc.Quote from: Xenon Photon on April 20, 2015, 08:39:32 pmThat's neat!