#70

Hi all, can anyone confirm the i2c connections to TRS, I’m making connections today for the 16n.

Tip to SDA
Ring to SCL
Sleeve to GND?

#71

ya that’s correct…i’m having issues communicating from my FB to my TT using what i’m assuming is a similar modded trs to i2c cable. how did things go for you?

#72

Thanks for your reply. I don’t have my 16n yet, was just modding a mult in preparation for it’s arrival hence can’t tell you if it works. What issues are you having?

#73

oh nice, my issue is that my tt won’t determine the fader values of my faderbank over i2c. maybe @scanner_darkly can solve it? i checked the modded trs to i2c cable w a multimeter and everything works. the faderbank is acting as a follower as the 4.7k resistors were left off. aside from basic communication from the faderbank to the tt, i was hoping to send messages from the faderbank through the tt to the er301. not sure if that’s possible but seems like it should work.

#74

correct, minijack is:

sleeve - GND
ring - SCL
tip - SDA

@okyeron we should add this to the guide!

3 Likes
#75

sounds like you need pull up resistors, since your 16n doesn’t have them, and you’re not using anything else that would provide them (like TXb or backpack). this is just a guess though, as i2c is a bit of a voodoo, and i’m not an expert in hardware. but if you can borrow a TXb or backpack from somebody i’d try that.

16n Faderbank: build help, dev suggestions
#76

from what I understand the pull-up resistors are intended to connect the fb directly to the er301, ansible or txo which would place it in master-mode. also i forgot to mention i am using a backpack on the tt.

#77

sorry it’s the firmware that places it in mastermode.

#78

pull-up resistors must be provided by at least one device. i’m not sure teletype alone provides that. the backpack will, however.

with everything connected, are you able to send i2c from teletype to er-301? if it works, the next thing to try is update 16n with leader firmware and see if it can send to er-301 directly (you will still need to have backpack connected for pull-ups, just don’t send anything from teletype at the same time as multiple leaders are not supported).

no, the leader/follower are two different firmwares. pull-up resistors don’t control the mode, they just provide the hardware needed by i2c.

#79

iwith everything connected i can send i2c from the tt to the er301 yes.

oh i see i was under the impression that the fb could be loaded with the follower firmware and communicate through the tt to the 301.

makes sense thanks for clearing that up.

#80

yes, 16n can be loaded with either the leader or the follower firmware. teletype can only poll values from 16n when 16n is running the follower firmware, and you can only send directly from 16n to er-301 when it’s running the leader firmware. in the setup when you have both teletype and 16n connected to er-301 you want 16n to run the follower firmware (as multi leader setup is not supported), and then you use teletype to poll 16n values and pass them to er-301.

instructions on how to load 16n firmware should be in the 16n thread.

2 Likes
#82

I’m not familiar with the Jetson Nano so not sure I can offer much specific advice on it’s setup. That being said, problems usually come down to either leader/follower settings, addresses being set correctly or device startup order.

What other devices are you working with here? Which device is set to be leader?

#83

Stumbled upon a nice video with little snippets that firmed up a a little of the blurry edges for me on a few things i2c related and thought I’d share:

Fun fact: hadn’t realized that It’s “I squared C” (eye squared see?), not “i two c”.

1 Like
#84

This post in lunchbox case thread:

sparked my curiosity about using the palette cases to hook up faderbank i2c to teletype. It looks like internally the midi jack is passed through to a 10 pin connector on the psu. So theoretically I need a 10 pin to i2c cable? How would that work? I’m definitely green when it comes to this stuff, and not even really sure where to start looking. This seems like a decent use case for the trs-midi in the palette cases so it would be nice to see it documented somewhere.

#85

Here’s the mapping for the internal connector to the TRS jack on the Intellijel Palette case

trs-map-intellijel-palette-case

You could just use a 3 strand jumper cable with separate ends (like below, but just 3), or 3 separate jumper wires.

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Eurorack: discussion, advice, learning, questions (archive)
42/54 hp Lunchbox Inspiration
#86

Thank you! Such a simple solution. Excited to try this out.

1 Like
#87

re: TXb

i’m absolutely not suggesting someone do this, but has anyone blown up their modules putting 10V into the i2c lines?

it seems like a very dangerous accidental plug-point. in past research i found some i2c hotswap ic’s, but i’m not sure they protected against big voltage. it might be worth collectively putting some time into creating a schematic solution for 3.5mm stereo i2c protection— which should be on all devices (ie, TXn and 16n and case-jumpers, etc)

#88

16n has a bunch of diodes around the i2c pull-ups - and I’ve not actually paid attention to if those are there to prevent this problem. @infovore can you confirm?

1 Like
#89

Yep, on 16n, D1-D4 are clamps between GND and 3V3 to avoid anything higher than 3V3 (or lower than 0V) on the I2C lines. I think I copied these from @bpcmusic’s schematics for TxX, etc, or maybe I remembered to do it. But yeah, the diodes are kinda mandatory, and for exactly this purpose.

2 Likes
#90

Hello, I’m having some i2c issues and hope someone can help out :slight_smile: I have Ansible, Txo, Txi, W/, Just Friends, and ER 301 wired to TT through a busboard.
I also made this stereo minijack chassis in 2hp to connect 16n faderbank to the busboard. Sometimes TT freezes forcing reboot. Or if I try to call a Ti.param or FB 1 TT freezes. It doesn’t happen all the time but occasionally.
Also experienced that TT won’t boot, I turned down power and removed the 16n jack, then TT will boot.
This one time TT freezed I slightly touched the mini usb of the faderbank and TT came back alive… Is this some ground issue perhaps? ( Faderbank has no issues sending voltage from the jacks )
What am I doing wrong? Is daisy chaining advisable in this setup for instance? Cable lengths are short but it’s crowded back there. This setup worked pretty well for quite some time… Any help is appreciated :slight_smile: thanks in advance