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9 years, 4 months ago.
Prototyping -> Production
Hi all. I'm a software developer, and I'm using STM Nucleo board to prototype a display device for use with a specific model motorcycle. I'm tossing around the idea of manufacturing and selling this device, although the expected volume would be very, very low (a couple hundred units).
One way to proceed is of course use the STM Nucleo boards as-is, and develop another board to handle all the interfacing and support circuitry. That is my "default" method that I know is a sure-thing that I can put together with the (limited) hardware skills I have.
However, the "right" way to do it is to have a single proprietary board that has the STM32 microcontroller, etc, on it directly. Looking at the Nucleo board, it seems there is a relatively small amount of support components for these microcontrollers.
So I guess my question is how "hard" would it be to layout a PCB to support the STM32 microcontroller, for someone with only novice PCB design experience? I have designed and etched my own PCBs, but not at nearly this level and complexity. Is it possible to support the STM32 with only a dual layer PCB? Does STM provide PCB designs that can practically just be copy/pasted into Eagle or similar to incorporate their boards into a custom design?
Here are my reasons for why I would even bother trying to create my own board to support the microcontroller directly:
- Size. The Nucleo boards are big, bulky things, and my interface board would make it even larger.
- Display. It would be possible for me to have a single board with a ZIF connector for the display, allowing me to use cheaper displays that don't have their own breakout type board.
- Cost. It *should* be cheaper to produce my own single board with everything on it, than producing a supporting board that also requires the Nucleo board.
Any thoughts on this? Is it absurd for someone with little PCB design experience to even attempt to integrate a microcontroller of this type into my own design?
Thanks!
3 Answers
9 years, 4 months ago.
ST provides Altium Designer project files for their nucleo board, you could start from it and strip out the unused stuff. http://www.st.com/st-web-ui/static/active/en/resource/technical/layouts_and_diagrams/schematic_pack/nucleo_64pins_sch.zip
9 years, 4 months ago.
I have made a dozen or so PCB s with LPC1768 LPC11U24 As well as the M3 version. Can never remember that part number.
All double sided. Boards. All working very well. But be aware that the cost of a short run of PCB s is massive £300 for 6 4*6" board's
I have not use any non - NXP parts. Although I do have the development boards.
Please be aware that some connectors can be more expensive than the whole populated PCB. So choose Wisley.
Ceri
9 years, 4 months ago.
I've designed a very generic STM32F103C8 based double sided PCB board and I've ordered them from Seeed Studio. It works perfect and I use ST Nucleo F103RB in my mbed projects without any need to do any modifications, since they are similar and they differ only in the pin count (STM32F103C8 is 48-pin) and memory size. You have to take care that you connect all of the power pins Vdd/Vss (refer to the datasheet of the specific that you intent to use microcontroller) and don't avoid any capacitors needed. Use only the I/Os you need in order to reduce complexity when routing the tracks. A helpful guide for PCB design for reduced EMI (you don't want your PCB to behave as a transmitting or receiving antenna that would cause problems to your own board or to other electronic devices) would be the following
PCB Design Guidelines For Reduced EMI http://www.ti.com/lit/an/szza009/szza009.pdf
Including an XTAL in your design, you would need to calculate the accompanying capacitor values (again refer to the datasheet of the microcontroller). If you use the internal oscillator, you don't have to worry about that. As for the price, the cost for mine was 30$ (including shipping expenses) , or 3$ per PCB (with max 5cm x 5cm size), not a bad price, although I am sure I have seen an even cheaper PCB fab somewhere. This of course didn't include the prices of the microcontroller and the various capacitors/resistors/headers needed, but it is cheap with respect to etching your own at that quantity and size (this was a 10 PCB board batch), and of course the quality is far superior with viases, silk screening etc etc.
Note though that designing your own board, might not worth the time nor the money since there are a lot of already assembled boards out there that cost very very cheap and probably some that are very small too, so try to investigate first what is out there. Ebay or Alibaba would be a good start.
This guy has got an STM32 running on a single-layer board with maybe 4 or 5 support components. https://www.youtube.com/watch?v=6JhCtATFVEU
posted by 23 Dec 2014Yes, you can have a very basic single side board, but in the end it might cost more expensive (for example, in my country a single side PCB with a photoresist layer costs about 3€, so it cannot beat a 3$/double sided PCB with vias,insulation,silk screening etc). The good thing with developing your own PCBs is that you control the time that you will have them and not a PCB house. You can also find cheap boards that are ready and they have a small size, for example like the following http://www.ebay.com/itm/STM32F103C8T6-ARM-STM32-Minimum-System-Development-Board-Module-For-Arduino-DHUS-/321569700934?pt=LH_DefaultDomain_0&hash=item4adf0c3c46
This one is easily programmable through the SWD and I guess since it has a USB connectivity, you can have a bootloader for updating the firmware. Since you are in the prototyping phase, you could try each of the suggested solutions and see which of them is better for achieving your goals both in terms of expenses and "time to the market".
posted by 23 Dec 2014