Smallest USB SAM with factory programmed bootloader

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Simple question: What is the physically smallest (i.e. lowest pin count) SAM with USB and a factory programmed bootloader?

 

It seems that he D and L series don't have the bootloader factory programmed, you have to load it manually yourself. To avoid needing a programming header I am looking for one than can be bootloaded over USB without prior programming.

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I just came across a note in the SAMD2x datasheet:

 

  1. WLCSP parts are programmed with a specific SPI/I2C bootloader. Refer to the "Application Note AT09002" for additional information.

 

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Ah, sorry, I should have been slightly more specific... It needs to have a USB bootloader.

 

I'm trying to build a small USB key style NFC reader. Would be nice if I didn't need to flash a bootloader on to every board. I'm familiar with the ASF USB stack so thought I'd stick with it, but if there are no suitable parts with USB bootloader pre-loaded then I might as well just use XMEGA or maybe STM32 or something.

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You could buy the chip pre-programmed I expect (from Microchip), check

https://www.microchipdirect.com/...

/Lars

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Aye, that's true.

 

I noticed that the Atmel USB bootloader for SAM D21 isn't based on DFU, and they don't seem to provide one that is. Then again the ASF USB stack doesn't support the runtime component of DFU either.

 

Kevin Mehall has a USB stack for SAM that does support DFU, but doesn't support HID. I re-ported it to XMEGA (his code seems to be broken) and added HID support, as well as a general fix/clean-up and performance enhancements for that architecture. Only issue there is that I have been unable to gather all the necessary hardware to run the USB-IF tests to certify full compliance with the spec, where as Atmel's stack is known to be compliant.

 

STM32 has a DFU-ish bootloader and runtime support. Documentation for their libraries is terrible. Haven't looked at NXP in any detail.

 

XMEGA seems like the best option; as much as I would like to play with the SAM D21 getting USB and DFU bootloader stuff working is a lot of effort for little gain.

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How about SAM4S? Comes in a 48-pin QFP and has SAM-BA in ROM which supports USB if the right external Xtal is hooked up. Shows up as a USB COM port.

 

Steve

Maverick Embedded Technologies Ltd. Home of wAVR and Maven.

wAVR: WiFi AVR ISP/PDI/uPDI Programmer.

Maven: WiFi ARM Cortex-M Debugger/Programmer

https://www.maverick-embedded.co...

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scdoubleu wrote:

How about SAM4S? Comes in a 48-pin QFP and has SAM-BA in ROM which supports USB if the right external Xtal is hooked up. Shows up as a USB COM port.

 

Sigh. Why a USB COM port? That means you need a driver.

 

With DFU+WCID you don't need a driver and it works with open source tools. With HID you don't need a driver. COM port is pretty much the worst option.

 

STM32 does come with a DFU compatible bootloader but you need their driver for it. The lack of WCID support means that you can't customize the VID/PID unless you also buy a signing certificate (although I think someone was offering free ones for hobbyists).

 

I think I'm just going to use XMEGA, my own USB stack/bootloader and a little pogo pin header for initial programming.

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I seem to recall that only Windows had trouble with CDC compliant USB serial devices, and that Win10 finally fixed the stupid behaviour (of requiring a “driver” which was little more than an entry in a .inf file).

So with Win10, Macos or *nix, it should just work.

Steve

Maverick Embedded Technologies Ltd. Home of wAVR and Maven.

wAVR: WiFi AVR ISP/PDI/uPDI Programmer.

Maven: WiFi ARM Cortex-M Debugger/Programmer

https://www.maverick-embedded.co...

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Yeah... I think you are right, Windows 10 can finally use CDC devices with the standard driver even if there is no .inf file.