Amazing new board running Espruino #2295
Replies: 36 comments
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Posted at 2015-07-08 by @gfwilliams Wow, looks pretty awesome! What's on it? So the green board is just a breakout for the LQFP? |
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Posted at 2015-07-08 by the1laz It's an STM32F401RCT6, on an eBay breakout board for LQFP packages. I can't believe it actually runs, it looks so messy. It's pretty much just all the VDD and VSS pins hooked up to 3.3V from the serial-usb adapter. I've put in all the recommended capacitors and I used the SWD pins to load on Espruino using the St-link from my Nucleo board. Just trying to get a feel for what's required for an stm32 board to work, just like a breadboard arduino...except there's no breadboard. |
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Posted at 2015-07-08 by Loop looks great! |
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Posted at 2015-09-17 by the1laz And here's a significantly less hacked together one! I got the boards from Oshpark for the first test run and soldered on what I needed to get it running. I managed to get the chip on without messing up the soldering and the rest of the components went on fine. The only problem I've had is that I got supplied 2.8V regulators instead of 3.3V ones! So the board runs, but I have to replace the regulator before I can try it out with some 3.3V peripherals. Attachments: |
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Posted at 2015-09-17 by @gfwilliams Nice! looks good. Are the 5x2 connectors on the sides to interface to something specific, or did it just seem handy? |
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Posted at 2015-09-17 by alexanderbrevig Nice! What are your thoughts about Oshpark? It's on my "to try" list :) Those headers made me think that it's possible to 'mate' two of these boards together. Dual processor Espruino? |
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Posted at 2015-09-17 by @gfwilliams I use oshpark all the time - I used it for all the Pico prototypes. They've been fantastic for me at least - and a really nice feature being able to upload Eagle files and see them rendered out as a finished board :) |
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Posted at 2015-09-18 by the1laz @gfwilliams - the two 5x2 male headers both have power, shared i2c,2 digital pins, 2 analog pins, a shared pin for interrupts and another shared pin. I initially made an ATMEGA328 board with an identical header layout, for using around the house for sensors and small projects. The idea is that peripherals or breakout boards will all use the same 5x2 pinout so that I can easily switch up processor boards or connect different things to them without having to resolder, redesign, have tumbleweed wires or any other issues. For example, I have a sprinkler controller that has the processor board connected with the 5x2 to a storage board that has all the power regulators, relay, lipo management connected. Now I can replace it with a board running espruino if I want, or add a flowmeter and soil moisture measurement to the other header without disturbing anything. @AlexanderBrevig - they're pretty good, especially for initial prototypes and tiny boards (like adaptors that are only a couple of square centimetres). They were prompt and the boards are great quality. I think I'll usually go somewhere else if I want 10+ boards, but they're really good value for your first run where you just want to see if it all works, if you've made any mistakes, or if you'd like to improve the design. As for that female 5x2 header, that's not for a dual-processor setup. (although, I have been wondering about a good system for hooking up multiple-processor projects. Eg, espruino board, esp8266 wifi and separate stm32 driving graphics...) that header is an SPI + ISP header. It has all the spi pins, plus a couple for for chip selects, etc. plus NRST. The layout is suitable for slotting an NRF24L01+ straight in. The board is designed to be a very compact and capable sensor node. :) |
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Posted at 2015-09-18 by @gfwilliams That's a great idea - I haven't come across someone developing a 'standard' header for their home projects. It's a really neat idea just being able to swap an old processor board out with a new one. (If you wrote that all up, I'm sure hackday.com would feature it - they love that stuff :)
Yes - I've used Ragworm, OSHPark and DirtyPCBs. The OSHPark ones are by far the best quality and reliably so. DirtyPCBs is acceptable an cheap, but the quality seems to vary. Ragworm were fine, but the edges of pads and traces just didn't 'feel' as good (not sure how to quantify that!). |
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Posted at 2015-09-18 by DrAzzy I used to use OSHPark, but now I use DirtyPCBs almost exclusively. I have found nothing to complain about on the quality of the boards. My problem with OSHpark, aside from the higher prices for a smaller number of boards, is that they manage to take just as long as DirtyPCBs+DHL shipping, despite the fact that OSHPark is domestic... Also, I don't like ENIG much - it's all sexy "oooooh gold!", but the solder seems less eager to wet it than with HASL. Regarding price, DirtyPCBs is just incredible. Near the start of this week I ordered 2 4x4 designs, ~10 copies each, with DHL shipping, for $65. I'll have them next week. And since you can panelize the designs there, you don't have to waste space; there's always something you can put in the extra space. That's where a lot of these come from: https://www.tindie.com/products/DrAzzy/bare-board-various/ . I've tried to resist the call of a homebrew "standard header" for around the house. My experience with all these attempts at general purpose headers is that it's hard to get something that is as flexible as you need to cover what you'll be doing in a few months, without involving too many pins for other applications, or "Oh man, if only I'd connected pin X to something on the header, I'd be able to use the header for this device - but I didn't" type situations. I rolled my own OOK RF protocol, but I've never felt like I have a good enough handle on future requirements to do my own header pinout, since I could potentially have a whole bunch of devices made before I realized my mistake. |
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Posted at 2015-09-19 by the1laz @gfwilliams Getting around to documenting things properly isn't really happening right now. But one day I will! I actually got the idea from here: https://maniacbug.wordpress.com/2011/04/03/arduino-box-header-platform-2/, I just boiled it down a bit more and made it 3.3V and not so Arduino-specific. @drazzy with dirtypcbs, do you have to connect all the panelized boards and break/cut them apart yourself? |
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Posted at 2015-09-19 by DrAzzy Yeah, you connect them in the design, with ratbites, and break them apart yourself. They break pretty easy (though I've never had a design where the placement of the ratbites was challenging, as it was with the pico as you may recall) What support circuitry do the STM32's need? Do you build your own firmware? |
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Posted at 2015-09-19 by @gfwilliams @drazzy, I'm really interested in those panels - they turned out well. Don't want to sidetrack this thread, but please could you help to explain how you did it here? http://forum.espruino.com/conversations/274571/ |
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Posted at 2015-09-20 by the1laz @drazzy - just a couple of pullup/pulldown resistors and an assortment of bypass capacitors. It also needs its 3.3V from somewhere and 0/1/2 clock sources depending on your needs. It seems quite resilient to things like missing capacitors and voltage range, but I've been reading up about bypass capacitors and grounding and it looks like there's plenty of other reasons for getting the capacitors right, it's not about getting the MCU to run. I'm running Espruino. Because the chip is so close to another board (the pico) it was quite easy to add a board file and an entry into the makefile. I'm still blown away by how easy it is to go from blank chip to javascript console! It's going to be great being able to telnet into sensora and just reprogram them on the fly! |
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Posted at 2015-09-20 by DrAzzy How do you get the f/w onto them? Do you have the Pico bootloader, or do you load with that serial flash thing? (I've never used that) |
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Posted at 2015-09-21 by @gfwilliams Check out the bottom of the pico page - there are links and commands there, as you need it if you want to replace the Pico's bootloader. The bootloader will only work if you've got an external crystal though (I think) |
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Posted at 2015-09-21 by the1laz Thanks, I'll give it a go. |
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Posted at 2015-09-21 by @allObjects
Sometimes (the - cumbersome - experience with) a '(mini) shrimp' is needed to become 'self-convinced' to actually use either Espruino standard or Pico board! ...and all other tries are interesting but more than a waste of time - and way more than the saved money - in the light of the final goal to achieve... I'm not even sure if shrimping is really cheaper than standard or Pico Espruino board, because you need 'all the other things' as well... (you can build your own plane for the journey of building a plane, but for journeys of going places, you let other do that...). It is the question of 'what is the core business' I want to be in. Therefore, it becomes a 'marketing vehicle'... and smartly done, it is not a push-away, but a pull-in. May be a special 'shrimping' conversation on the forum - or even a regular page on the main site (@gfwilliams?) - could be enough to have the same 'just-buy-an-Espruino-standard-or-Pico-board-(to-stay-sane) -marketing' effect. This was by the was a part of having not doubted and delayed a blink of an eye to get a board despite the price as compared to the cheapo-Arduino-things... and I also know what it means to get 1st the hardware done and 2nd the base software reliably working before you can begin to work on what you really want to work on... For many this mindset is a challenge because the out-of-pocket seems to be more tangible than spending countless hours of (not really available personal) time... |
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Posted at 2015-09-22 by DrAzzy "Shrimping"? "shrimping" sounds like a euphemism for some deviant sex act, not something to do with electronics... I've never heard it called that. Also, that page implies that the decoupling caps are optional on AVRs. They are not, and boards that omit them will suffer from unpredictable instability, particularly while programming the chip. I've more often seen "shrinkify" for moving devices down onto smaller boards (smaller boards and smaller chips, ie, ATTiny)... I'm not really sure what people would shrink to though - you can make something a little cheaper than the pico, but not by much, unless you've got @gfwilliams's ST connections. The STM32F401 that the Pico uses is like $8 from digikey, and other STM32 chips are in the same ballpark, and since you need your own board made too... It's certainly not like on Arduino, where you can replace a $30 uno with a $2.25 pro mini knockoff or $4 breadboarduino. And there ain't no way you're going to get something physically smaller than the pico! |
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Posted at 2015-09-22 by @allObjects It's not the shrinking... it's a motaphorically for minimalist (also smimplified) - the poor tinkerer's version. It's not a size thing at all... because the small breadboards have about the same footprint as an arduino (uno). The challenge with the cheap STM32 boards is the fact that they are STM sponsored/marketing tools to the get develpers - and tinkerers - used to the hardware when on low budget - usually in schoool or while in school in their hobby time - and later, when in real business/workplace, will pick what they have experience with - and finally can materialize their dreams in real setting with elaborate boards. And with the fineprint that does not allow to use such boards as components in a product... a limitation which Espruino does not have - by 'overall design'. |
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Posted at 2015-09-22 by DrAzzy Yeah - the cheapest option seems to be a Nucleo board. On that topic, I should be getting some Nucleo-to-sane-pinout (grouped by port, in numeric order, labeled) adapter boards this week. Assuming I didn't botch it, I'll put em up for sale on Tindie - I can't be the only one who can't stand the un-labeled, randomly distributed pinout. It's worth noting that in Arduino-land, you can get a pro mini with free shipping from china for like $2.25, which is about what you'd pay for the bare chip. So, so the breadboarduino is not a poor mans option in arduino-land either. |
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Posted at 2015-09-22 by @gfwilliams I met someone at a UK maker faire that was pushing 'shrimping' - (shrimping.it I think). I guess the name is supposed to seem more friendly, but it does sound kind of odd :) Due to a really shitty decision by UK education authorities, for some electronics projects in school kids absolutely have to use bare chips (no modules allowed), so they're actually very limited with what they can do. I think it probably 'feels' better using the bare chips - although I agree about the costs of the Chinese clones. I had to buy the chips for this new batch of Picos, but buying in quantity in China makes a massive difference - I can buy them for at least 1/4 of the price you'd pay if you went to DigiKey or somewhere. I'd be pretty sure that trying to make your own Pico will end up costing you more than the $25 they sell for. It's just a shame ST don't do DIP packaged STM32s - they'd be significantly more interesting with Espruino on them :)
You know those boards have |
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Posted at 2015-09-22 by the1laz @allObjects yeah, the whole point was to get that experience, to get a feel for what I was working with. Assembling my own boards does turn out a bit cheaper than the pico. Here's a quick breakdown: So it is costing me ~$14 per board when buying parts for 15 to 20 boards at the moment. Getting the STM32's that cheap was a one-off, and because they're lower spec than the pico's means that it'd cost closer to $20 each, ignoring setup costs, accidents and prototyping. Considering assembly, handling, and distributor costs, I'm pretty impressed at the pico's price! |
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Posted at 2015-09-22 by DrAzzy Man, I'm clearly getting chips from the wrong place. |
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Posted at 2015-09-23 by the1laz $8 is about right for individual stm32f4 chips. If you jump onto octopart and get them in some sort of quantity, they go down to $4-$5 (below $4 for bulk). If you find someone trying to dump the last 18 of them that they have in stock, below $4 is possible. :P |
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Posted at 2015-09-23 by the1laz Btw, something that isn't covered in my cost breakdown is assembly by hand. It takes ages. Economically, I'd definitely be better off grabbing a heap of picos. I'm making my own boards for the form factor, getting the functionality just how I want it, and for fun! |
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Posted at 2015-09-23 by @gfwilliams
I know, that was really good value! But yes, it's the fun of doing it yourself :) |
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Posted at 2015-11-08 by the1laz An updated version of my board, using cheaper crystals, usb mini (much sturdier), no more 1.27mm headers and hopefully better trace routing for decoupling (although I have no idea how to check or if I'll ever care). Unfortunately all the silkscreen labels didn't make it onto the board, not sure if they were too small or overlapping parts. Soldering the mcu is getting much easier with practice, it's actually a bit easier than doing all the capacitors! Now I'm just waiting for some daughter boards to be fabricated: a neopixel backpack, a 2x mosfet output, an adjustable boost regulator and one that has a temperature sensor, voltage divider, led and button.Attachments: |
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Posted at 2015-11-09 by @gfwilliams Wow, that looks like a really tidy little board now :) |
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Posted at 2015-11-09 by the1laz Thanks! Espruino is really what got me to jump from doing these with a Atmega328. Being able to plug in and start talking to sensors using a console interface (plus javascript!) really made prototyping a blast. Thanks for the suggestion of the usb dfu bootloader, I gave it a go this time and it worked great. |
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Posted at 2015-07-08 by the1laz
Isn't it pretty?
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