Polyphonic earthsea for trilogy/ansible and er-301/just friends/txo


Would there be consequences to sending power into i2c lines?


i think you need power as i2c protocol is open drain, meaning that SDA and SCL lines are high when there is no communication, and any exchange is done by pulling them low. teletype will provide that voltage while trilogy/ansible won’t.

my assumption was that this configuration would be the same as using, say, ansible, just friends and teletype with a teletype i2c backpack together. changing ansible to run as i2c leader in this configuration does not affect the hardware. i assumed disconnecting teletype wouldn’t affect anything on the i2c bus either, but perhaps this is not the case. i don’t know much about the hardware side of things, so can’t really comment.

@tehn - could you comment whether it’s safe to use trilogy/ansible as i2c leaders with powered i2c backpacks but without teletype connected?


I more meant, if a 12V power bus board pin connected with an i2c pin, would that cause issues? As in physical contact.


i would assume there is a high chance of something rated for +3.3 or +5 getting damaged when connected to higher voltages.

same logic applies as, say, using a flying power busboard - i would not leave it free in a case where there is a chance it might come into contact with any of the modules.

regardless, at this point i do want to make 100% sure that using i2c in the manner i suggest in this thread is safe. i most certainly wouldn’t want to recommend something that would result in damaged modules.


Cool! And for my part, I’m not sure I want to be selling folks boards when there’s a chance they might do damage to their hardware, even if it’s noted as a risk that the user would assume.

Curious to hear what the verdict would be. It also has me thinking about something Offworld-like that is an enclosed small board specifically for this purpose.


yes backpacks are safe with trilogy without tt.


So how about something like this:


modular power header in, 6-pin i2c-in and 2 6-pin i2c outs which could go to a ribbon cable with multiple connectors (flying bus cable) like the one trilogy modules use (?)

EDIT - looking back at the tt-busboard files - is GND not actually connected/needed on the original busboard? (or am i not seeing some groundplane or something in the pcb layout?)


multi pattern and voices is really intuitive. congrates!
actually easier for me than original firmware.
would love to try out i2c if you get around that extra button position for JF/i2C 64.


Super Noob question, where are the firmware files posted?


i had to remove them temporarily and wasn’t able to restore from the old post. i’ll post new files when i have a new version ready.


Ah great, thought I was blind, tried looking everywhere!

Been trying out Ansible Earthsea and can already imagine the improvements in the PolyES version, looking forward to your update!


new betas posted. what’s new:

  • midi keyboard support
  • bug fixed with clock input on ansible
  • ansible buttons work for next/prev pattern now
  • ansible reset input fixed
  • knobs are mapped to mod buses
  • new parameter for txo: waveform fine
  • bug fixed: just friends volume of 0 didn’t work
  • long press on front panel button will save current preset
  • LED on ansible indicates current pattern start

midi support for now is just playing live, and any cc value is mapped to mod bus 1. i’ll be adding midi learn in the next beta.



Totally untested quick layout. Im in no urgent need for one so until I have to order more boards next week (which arrive a month later) I wont be able to build and verify. But if anyone is impatient this is just a remix of the TT busboard, with the power and i2c headers relocated to mount to ansible. Without source files for ansible i cant be exact, but they both seem to be on a 2.54mm pitch grid so it was easy enough to work out


Wonderful work! Will you be planning on adding a midi record function?


yes, midi recording and midi learn function (to assign CCs to mod buses) is planned for next version.


Have finally installed this and enjoying it a lot!

Wondering though is there is an issue with the preset button, cos when I press it on the front panel of Ansible, nothing happens, neither with short or long press.

The LED doesn’t light up neither to indicate current pattern start, it doesn’t light up at all on mine.


thanks, looks like a bug was introduced in the latest change that broke the front panel button functionality in ansible. i’ve posted a new beta for ansible that should fix that.

also confirmed the LED is working - please note it’s for the current pattern only, so if the pattern you’re currently on is stopped it will do nothing.


Thanks, will try it tomorrow and will not the led light too!


Just installed your last version and checked. Presets work, the LED light works BUT not when receiving external clock.


ah i know what the problem is, will fix in next update! this will also affect pattern start events assigned to any outputs or mod buses.