Rabidprototypes TAU not recognized by the system; Cannot upload when it is.

Hi All,
I have a nice little board, the Rabid Prototypes TAU - a smaller version of the Zero and the Feather M0 - only 22 pins, 4 Analog pins brought, w/ IIC and a hand full of other I/O. 32 bit Cortex w/ 12 bit A/d. Very compact. Rabid Prototypes says it uses the Zero bootloader. I started with the IDE Ver 1.6.9. It would not be recognized on the port that I was using for the Feather M0, but was it was found after changing to a different USB port. System loaded it at COM10 as Zero Bootloader and it would program OK. That baffles me. He suggested to upgrade to the latest nightly build as it recently fixed an issue with the board. I d/l the build but am not sure how to get it to install. So I went back to 1.6.12. Here is what happens:

Originally, the system (Pentium 4, Win XP SP3) would not recognize the board. Called it a "Tau or a "USB Device", but could not find a driver for it, and it did not show up on the Tools/Port menu. I changed ports and it did eventually pick it up as "Zero Bootloader". With IDE 1.6.9 I was able to program it with my sketch. After upgrading to 1.6.12, it will not recognize it at all. Most of the 4 USB ports on the PC call it a "USB Device" or simply sound three bonks and ignore it. I was able to find that port in the Device Manager and locate the driver for the Zero. There are 2 versions in my system - and Tried them both. Sometimes the system does identify it and assign it to COM13. Problem is that the IDE cannot upload to it.

The board is correctly found in the Tools/Board menu and the following 2 additional boards are listed in the Additional Boards Manager URL in File/Preferences:

IDE compiles and links the sketch, then reports this after resetting (single or double-click after compiling before uploading):

"PORTS {COM1, } / {COM1, COM13, } => {COM13, }
Found upload port: COM13
C:\Documents and Settings\Admin\Local Settings\Application Data\Arduino15\packages\rabid prototypes\tools\bossac\1.6.1/bossac.exe -i -d --port=COM13 -U true -i -e -w -v C:\DOCUME~1\Admin\LOCALS~1\Temp\arduino_build_253481/Analog_Input_and_Display-test-8-I2C-TAU.ino.bin -R
Set binary mode
No device found on COM13
Send auto-baud
Set binary mode
An error occurred while uploading the sketch"

This happened after upgrading to 1.6.12.

Originally the IDE would close as soon as I plugged the board into the USB port, and if it is already plugged-in it would close before opening the sketch.

I may go back to 1.6.9 and see if it works again! The sketch was loading fine, and it is resident in the TAU and runs fine on its own.

Any ideas? What am I missing? And how do I install the latest nightly build?
Rebooted the PC several times, etc.

Thanks! I've only been playing with the IDE and Arduinos for the past year and have limited experience in the Arduino IDE.

I plugged in an Arduino U3 and it worked fine.


I plugged my bare Feather M0 in and it showed up (on one of the USB ports) as "Adafruit Feather M0" on COM 8. Compiled and uploaded OK.

Unplugging it and plugging in the TAU, the Hardware Manager calls the same USB Port |Arduino Zero Bootloader" on COM 14.


That would be true... Not all boards use the same com port sometimes even among the same board type.

I have two MKR1000's and they both use different com ports...Same for my UNO's

Windows especially allocates com ports in sequence for new devices.
Chances are the PID & VID for one board is different from the other too !

OK, that sounds OK, but wonder why I cannot get it to properly recognize the board? In Hardware Manager I point it to the driver folder for the board... Reports it "Cannot load the driver" or similar.

As its not an OFFICIAL board that question may be better suited to the source as I have no idea what they use or how they use it ?

Maybe they require a line (JSON) in the “Additional board manager” in the preferences ?
Maybe its a different driver from real Arduino’s ?

Add some links or go to thier site and help sections ?


Not sure if it affects you but it took me about 5 seconds to find it.

kick-starters are great but often don't have the resources of companies such as Arduino or the amount of testers. Anyone fancy a BETA MKR ? NO not really its a prize possession.

Yes, I have the .json file in the Preferences Additional Boards Manager section for other boards. I’m fixing to email support there at Rapid Prototypes.


Funny thing is it finds the board just fine under 1.6.9 but not 1.6.12.

And I have no idea what to do with the files in the nightly IDE build. It might be there, but I could not find an install file or script to put everything where it goes…

Hmm can you roll back the boards version in the regular boards manager ?

ESP8266's used to have a similar issue and the trick used to be to roll back the boards version even with the JSON set up.

DONT use the nightly !
Bugs and such..its more for testers and the braver peeps

Thanks for the info re the nightly. I was skeptical, but it seems like something broke with 1.6.12 - it won't load the board.

Backing up to earlier board? Might be a good idea. Where do I find that? There is only 1 selection for that in the Tools/Boards menu. Thinking that is not it. I emailed the supplier with the issue description and screenshots and he said that the version of bossac pointed to was wrong. I deleted a folder and reinstalled the boards and it works on 1.6.9. When I tried to upgrade to 1.6.12 it won't load the binary. Trying 1.6.11. That one works. Strangely it changes the com port with different versions of the program with the board plugged into the same USB port. As long as it loads OK I'm happy.


Stick with 1.6.11 if it works.

Sometimes the IDE has issues with NON Arduino boards.

To roll back a boards version goto TOOLS, BOARD, BOARD MANAGER.

Select the board that you are using and check the BOARDS VERSION by clicking on MORE INFO
If there are other versions you can sometimes update OR roll back

Oh, of course! Thanks!