#28

in my setup, I have just one longish I2C cable with multiple headers and all of my I2C modules are connected to this very same cable. If you don’t have such a cable, just daisy chain all of them together.

the 10-pin power cables for each module should connect as usual to your power supply—I2C is not a substitute for powering a module.

#29

So maybe this will help?

At the left a eurorack power cable attaches to a TeleType-backpack (which gives power to the TT). Then there are smaller i2c cables connected from the backpack to various modules. At the far right the Telex’s are daisy-chained to each other.

As others have said - i2c is completely separate from the eurorack power bus.

EDIT - I’ve also just updated the “how do i connect everything?” section above - please re-read that section and let us know if you have specific questions.

3 Likes
#30

i just want to reiterate that most of the questions have already been answered in the guide. if something in the guide is not clear please post a specific quote so we can fix the guide.

3 Likes
#31

When making an i2c-capable device using a microcontroller (say, Teensy 3.x), how does one format i2c messages to work with other devices? Does it require specific formatting based on what will be the “follower,” or is it configurable in the device (ex. er-301)? I see that addressing is done in firmware, but I’m wondering how different channels are configured, etc. Is there a guide for this, too? Or is it more of a consensus among developers?

Trying to put together a new controller device and wondering how best to make it i2c capable. Thank you!!

1 Like
#32

relevant thread: Teletype I2C protocol

and check out https://github.com/scanner-darkly/teletype/wiki/II-protocol - this has exactly the info you’re looking for!

1 Like
#33

Wonderful, thank you!

Also just found this: Using I2C protocol in new hardware designs

#34

All great information I totally understand
Thank you
But Can I try this for a question instead ?
I do not have a backpack
I believe I read I could use the txb instead of the backpack

#35

Yes, you could. I2c does not care about the configuration of the modules. In your case you would just connect the teletype i2c pins to the txb. then as long as all the other modules are connected to txb it will work.

2 Likes
#36

Perfect Got it thanks

#37

This is probably stupid but without a TT is there anything I can do with i2c?

I have Ansible, JF, w/, and tetrapad…

1 Like
#38

Yeah, check out polyearthsea for your Ansible. You’d need a powered I2C bus but it would let you use synthesis mode on JF.

3 Likes
#39

Thanks! Another stupid question, what do you recommend for a powered bus?

I don’t build anything yet…

#40

There are several options for powered busboards listed in the guide at the top of this thread.

4 Likes
#41

Sorry if I’m being dense. I couldn’t determine from the guide above how daisy chaining works. I’m assuming this –

IMG_6397
IMG_6397.JPG480×640 102 KB

From TT I’m going SCL-SCL (etc) to 3 pins on ansible. From the other 3 pins I’m connecting SCL-SCL (etc) to JF. Does that sound/look right?

Also, should the new TT (black PCB) be able to handle an ansible, JF, and TXO+ without a backpack? Thanks!

2 Likes
#42

that looks right to me

#43

my old TT can handle Ansible, Just Friends and a Slashes without a backpack, you should be golden!

2 Likes
#44

At what length does unreliability begin to creep in with cables? Is 15cm, for example, be too long? I’ve seen comments on here saying that 30cm would be super long. I’ve got my TT placed next to W/ and Just Friends to keep things short, but I would like to break my chain and place my W/ somewhere else in the case, which would require a new cable.

And any fellow Brits on here, please spare me the “how long is a piece of string?” response :grin:

#45

my I2C cable stretches about 94 HP and I’ve had no issues

6 Likes
#46

I once had my TT and W// on separate ends of a 126hp row without incident. YMMV

3 Likes
#47

encouraging to hear both of your reports!