Chip Candidates

A project log for ESP8266 with True USB

Make it act as a USB disk and just copy files on it.

deʃhipudeʃhipu 02/20/2018 at 11:273 Comments

I have been looking through the cheap microcontrollers with USB support, and I have narrowed my list to two, with maybe possible third.

The first candidate is the venerable ATmega32u4. It has been around for a long time, there is a LUFA library for handling USB with some examples for the MSC device, and I have a whole bunch of cheap Pro Micro development boards I can experiment with. It also has a lot of GPIO pins, so it could also be useful for projects like #LAMEBOY for handling extra functions, like the buttons and backlight.

The second candidate is the SAMD11. Much more modern, cheap and comes in an easy to solder package. It also requires fewer passives — I think it can even work without the crystal. There is also a MSC device example for in the ASF3 library. It is however more of an unknown for me, as I have never before programmed any. I got a #DiXi board to experiment with it.

Finally, a distant third is the good old STM32F103 chip. It comes on the "blue pill" dev boards, and it also has some MSC examples. I have some limited experience programming it, too, so maybe it will turn out to be easier than the other two.


AVR wrote 02/20/2018 at 15:25 point

having mucked around with various ARM Cortex M series microcontrollers I have to say ST is one of if not the most easiest vendor to work with in terms of documentation and ease of use, they also have a lot of parts that are mBed compatible if that's your thing. The mBed functionality really helped us when developing SunLeaf years ago.

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Clara Hobbs wrote 02/20/2018 at 14:51 point

For everything you're talking about doing, I might expect the microcontroller to need more flash than an ATmega32U4.  Also, I'd suggest an STM32F072 over an F103 because they can do crystal-less USB.

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deʃhipu wrote 02/20/2018 at 14:56 point

Yeah, well, I will start with just simple MSC and serial, that should fit, I hope. The esptool idea is kinda secondary, and I could probably flash the chip myself, not through the esp8266 then, so less logic too.
Thank you for the STM32F072 suggestion, I will certainly look at it!

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