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16N Faderbank is Happening


Got my shipping confirmation today :+1:

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My faderbank is on its way :tada:

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@bpcmusic can you confirm the position of SDA SCL and GND are L > R when looking at the back of the txb when it is facing upright?




On the TXb, ground is marked by the white box on the PCB:

The two rows of pins to the right of ground are wired together. Since the TXb has no processor, it is indifferent to the signals passing down those lines. Pull-up is applied equally to them (when powered). That said, there IS a standard for the devices that connect to the pins and to the stereo 3.5mm jacks on the front.

To have a successful bus, here is the pin ordering:


More info on i2c can be found in this very helpful guide:

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Thank you! The issue lays elsewhere apparently–will report back to the thread once I have it up and running :+1:

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I’ve gotten successful i2c communication of 16n > ER-301 via txb :partying_face: . No idea what the issue was–after a few power cycles it just…worked :man_shrugging:

I notice a bit of offset registering at minimum fader value (e.g. ~.015 minimum value when using a USB wall adapter, and ~.026 when plugged into my MBP). I erroneously assumed this would coincide with #define MINFADER 15 in config.h. Is the offset expected due to the nature of the 16n circuitry, or is this addressable in Arduino? On the other hand it might be a custom control solution w/in the 301…



what kind of wall adapter are you using?

The offsets are to deal with component variances. When developing my small portion of the firmware, I found that there was some variance in the max and min values I would get out of the faders. The effect was that some faders wouldn’t make it to the full minimum value and/or maximum value. It felt quite broken. :wink: Adding in these small values for min and max worked to eliminate the problem across the six+ prototypes that I built.

Now - these prototypes were a bit different than the final version (they didn’t have the MUX chip on them). I wouldn’t think the circuit is behaving appreciably different in this regard between the versions, though.

It sounds like your wall adapter might be a bit hinky to give you that variance. If not - you can always adjust the min and max values to give you a little more tolerance on either end of the faders.

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Just a general apple product mini-brick. I changed the power source to an Anker PowerCore 20100 battery, and it cut the minimum offset to .006. I also notice that different USB cables generate different offsets as well, the data cable generating less offset than the standard charging-USB.

So for other readers/posterity: power source and USB cable types matter!

Currently have MINFADER set to 0–will it accept a lower value?

Thanks for all your time and efforts @bpcmusic :trophy:

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Um - unpredictable. Voltages measure from zero up on the Teensy.

Not sure why you would set a negative voltage. You want these values to encompass the very slight variance in your edge voltages on the faders so that they cover a predictable range.

On my Teletype input expander (TXi) I rely on calibration to manage these variances. Far better solution - but complex to get done for a 16n that never connects to a Teletype.


Also - not a big deal for MIDI output due to the controller value resolution. More noticeable when connected to the ER-301 or Teletype.

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Going for the most stupid question of the week: just received my faderbank, so when i connect it to my TXb with a short power cable do i also need to power it as well via the USB jack to the left of the i2c?!

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Yep, it requires power via the micro-usb

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Up and running & talking to my ER301, let the fun commence!!!

Did i read somewhere that there is some firmware to flip the orientation of the Faderbank?

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If you can make the change yourself in arduino—in config.h make sure REV 1 and FLIP 1 are uncommented :+1:

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Thanks, I’ll just stick with what I have then, not familiar with updating stuff with Arduino.

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I know how that feels, but I would encourage you to look into it. It’s mostly about installing teensyduino and a few libraries, uncommenting those lines and pressing send.

I’m pretty much a complete beginner, but did manage it. Can try to assist in every way I can if it helps and you feel like taking it up.



Hi Josker, thanks for the encouragement!! In actual fact @tomk already offered his assistance & with that assistance i managed to update my Faderbank this morning & all working well!!!



That’s so nice, glad to hear it!



Hi guys I got my faderbank from MS earlier this week and also installed the shunt to my rev 7 , Raph installed the pullup resistors and I have flashed the master hex to my 16n, I got a mininstereo cable going from the 16n to the ER and I followed the signal path the correct way I think, Now I know is a stupid question but how do I make it do a thing on the ER, I looked under connections and there is no signal of any kind, how do I assign a fader to the ER I guess is what Im asking, or even check to see if it made a connection, so far I dont see any activity and cant get anything to work , any help would be Appreciated!! also to clarify, Im trying to use the faderbank to control
The er I dont have a teletype




start at the bottom for configuration. then you’ll need to use the SC.CV units on ports 1-16 to get signals from the faders.

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You rock!! Thanks a lot man!!we have lift off!!

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