Tides, 2018 revision


#61

Oh, the Stages and Marbles source code and schematics have been released. A quick glance at the code suggests that Stages uses two serial ports, a left and a right, to chain modules, not I2C. Marbles has support for a debug port, not sure if that has potential to be repurposed somehow.


#62

Yeah, not I2C, but the same pins as the “left direction” connection:

I’m personally holding out for a rack full of Tides(es) connected via CAN. I don’t see a 120 ohm terminating resistor, I guess the cabling will have to provide for that! Though I suppose 104hp is much shorter than most cars/tractors.


#63

Hmmm, I2C uses open drain, doesn’t it, so it needs pull-up resistors? The two-pin header only has in-series resistors on each pin. And if it were intended for serial comms, you would expect a third pin for ground, like Stages has, would you not? Of course there’s a ground pin on the four-pin header right next to it, but a custom cable would be needed. Easy to make, just not quite as convenient as three pins right next to each other. Maybe the two-pin connectors are just for the automated factory testing mode? I think Marbles has something similar? Doesn’t mean they can’t be repurposed, though.


#64

I’d guess this. If 2018 MI is post-“Easter Egg in firmware”, it’s probably also post-“DIY expansion”, and anything expansion/communication-oriented intended to be utilized by the end user would probably come with a populated header.


#65

Looking at the Stages PCB and schematic, I agree - the left serial header connects to the same pins on the CPU via in-series resistors. Thus, I dare that that two two Tides 2018 could be made to talk to each other over the two pin header (plus a ground line), using the same protocol etc as Stages. Obviously the data payload would be different. So what uses could that be put to? Hmmm.


#66

Normalized Clock and Frequency maybe. Would open up for chained modules to work divisions of master frequency.
Or, dare I say it, a preset manager.


#67

It’s just a serial link to communicate with the factory testing program.

It’s there since Clouds/Elements :slight_smile:


#68

Aww. You should have let the blind speculation gone on for a bit longer :grinning:


#69

Yes… this will give Olivier fits of the horrors, but a small module with a small OLED screen and two encoders, and a few buttons and inputs (trigger/gate and CV), with 4 or 5 serial interfaces, each of which can be connected to a Plaits, Marbles or Tides via a three wires cable (TX. RX, GND) to allow additional parameters to be set, and yeah, presets to be recalled. The trigger/gate and CV inputs would be so that the presets themselves could be put under voltage and gate control.

The module I’ve described is a lot like an O&C or Temps Utile, but maybe using a Teensy 3.6 which supports pins for five hardware UARTs… hmmm.


#70

That would be quite neat - it’d also make dac calibration very easy! It’d also open up a few fun ideas with marbles - hmm…


#71

The problem with that is that it completely destroys the idea of one-knob-per-function, in the sense that after preset-recall, the position of the pots will bear no relation to the values they would normally indicate.

While there are lots of standalone synths that have pots and sliders, rather than endless rotary encoders, where this situation applies, I have a feeling this is exactly the kind of scenario @pichenettes has been seeking to avoid with the more recent MI modules.

In fact, the elimination of the single multi-function pot on the original Clouds (for exactly the above reason) was stated as one of the main reasons for it being discontinued.


#72

I suspect this suggestion is not for Olivier to manufacture but for people to hack with for a laugh :slight_smile:


#73

Yeah, sure, but you’re assuming that the “presets” would affect parameters which are set by the existing knobs and/or CV inputs. What I had in mind was presets for other parameters in alt-firmware that can’t be set by the existing controls, such as, say, which wavetables to use for a “Sheeps” mode for Tides 2018.


#74

@pichenettes can I ask why you opt to use a switching reg module, instead of a discrete solution? I am just curious.


#75

I originally designed a discrete solution using a TPS563200DDC.

More PCB real estate, more risks of doing something stupid, for 30 cts saved per board. Not worth it.


#76

My thoughts here were to calibrate the dacs in the new modules as well as play with some ideas on marbles - alternative generative algorithms (machine learning) and also tweak extra parameters for those algorithms…


#77

That’s kind of what I thought, although I thought the price difference would be more.
There are so many switching reg ICs out there it’s tough to even know what’s good unless you spend a ton of time looking and comparing.

I have to avoid thru hole like the plague (a different industry, not synths) so I’ve never even looked at these boxy ones. I have been curious about those tiny modules TI makes, but feel sketchy about BGA for a power supply. That and I already have a few go-to designs I basically copy+paste for every project that are small, cheap, and low component count.


#78

That diagram definitely doubles as abstract art.