Friday, 14 June 2019

i2c bus and synths

A little bit of info re the I2C protocol and how it relates to midi and synths.
It's also called  rather confusingly IIC or i2c or the I²C (Inter-Integrated Circuit) interface.

It was originally developed in 1982 by Philips to allow integrated circuits in televisions to communicate
it has since evolved into a standard communications method used by a myriad of devices.
It's a digital communication protocol and it looks like it's becoming more common in the synthesizer world.

Buchla used this back in 2005 when Don developed the 200e.

He used this on the 200e's internal "power" bus (obviously it distributed more than just power):
Pin 8 = Yellow: i2c clock
Pin 9 = Green: i2c data
This is how the modules talked to each other without the need of patch cables... how internal midi, preset management, clocks, etc were distributed within the 200e environment.

It appears that i2c uses just 2 "wires" to transmit the necessary data.
They are:
SDA (Serial Data) – The bi-directional line for the master and slave to send and receive data.
SCL (Serial Clock) – The line that carries the clock signal.

Actually a i2c bus has two signals, along with a power and ground connection.
There are two pull-up resistors attached to each signal line, they pull the bus up to the supply voltage when it is inactive.

I2C works with the concept of “Master” and “Slave” devices. The master device provides the clock signal and initiates communications with the slaves. It requests data from the slaves individually. An I2C bus can have multiple masters and slaves, but only one master can be active at any given time.

Interestingly the Monome Aleph and the Teletype also use i2c.

The Aleph ingeniously use a simple 3.5mm stereo jack. It's just labeled  "ii"

According to their website:
" the bus is addressable (multiple devices on a chain), fast (400k), and easy to implement on various platforms (ie, an arduino)."

I'm in the process of building a Eurorack Faderbank which uses this protocol.
The Faderbank uses a Monome stype i2c connector TRS jack (tip is SDA, ring is SCL).
"It can be used either as a master device, which could connect directly to (e.g.) an ER-301 or monome Ansible, or as a bus device for a monome Teletype".
The Faderbank uses a Teensy 3.2 microcontroller

I understand that the ER-301 from Orthagonal Devices, SSR labs MATRIXARCHATE, Just Friends, the  Monome Teletype, Ansible & TXo (just like the other Monome trilogy modules (White Whale, Earthsea, Meadowphysics) also use i2c.
----------------------------------

The I2C bus is a standard bidirectional interface that uses a controller, known as the master, to communicate with slave devices. A slave may not transmit data unless it has been addressed by the master. Each device on the I2C bus has a specific device address to differentiate between other devices that are on the sameI2C bus. Many slave devices will require configuration upon start up to set the behavior of the device.

-----------------------
Teensy 3.x
The Wire library allows you to communicate with I2C devices.
Pins 19 & 18.
https://www.pjrc.com/teensy/td_libs_Wire.html


Links
MidiBox Hardware
Monome Aleph
ER 301
Circuit basics
Arduino and i2c
Monome teletype iiheader
faderbank
Matrixarchate 
MST MIDI to CV Converter - sYNTHROTEK


I'll add to this page over time.
I'm not a Buchla technician so please let me know if there are any mistakes or BS.

Sunday, 9 June 2019

Percy Grainger's Synthesisers

Metro Modular Boethian Wheel - Model 660 - first patch experiments

I had a chance to catch up with Justin of Metro Modular on the weekend.
He explained to me a bit about the 660 module.

There are two inputs at the base ... the Banana is CV. Tiny is audio.
At the top of the module we have the outs -- also audio & CV ( The red bananas are gate outs).

In the centre we have the wheel composed of 32 LEDs.... 8 in each quarter.

The theory is that if you put in two audio sine waves that are 90 degrees apart, like say the individual pole outs on a self oscillating VCF the MM660 will generate square waves at 1x, 2x, 4x, 8x, 16x, and 32x the frequency.
These are available as gate & audio outs.
They are also summed to give a arp like effect (similar to the korg Poly-61 like sawtooth/staircase ARP).

You of course don't need to use just sine waves inputs and both inputs don't need to be in phase with each other. This is where things get interesting.

I did a quick patch using a 281r,292r, 266r, a wogglebug and a CV processor.
I didn't have an audio source so we just used the CV inputs. This was interesting as the 660 became a sound generator.


I've fed the audio outs of the 660 into the 292r - low pass gate.
I'm just using the 292r as a VC mixer

So in this patch the only sounds are from the MM660.
There is no other audio source like a VCO. The MM660's LEDs are triggered using the outputs
of two channels of the 281r function generator which are in self cycling mode. I'm just playing with the 281's envelope's attack & decay.


The wogglebug and 266r are providing CVs to simply open and close the 292 VCAs

The spinning of the LEDs indicates the relationship between the two CV inputs.

Changes in their phase or shape will move the LEDs.
At LFO speed, very little audio is generated, but at higher rates we have sound.
......................


Some Links
+ Metromodular Facebook
+ Metromodular Youtube
+ Metromodular website  

----------------------------
My Metromodular index page
--------------------------------- 

Boethian Wheel Module - The Consolation of Philosophy

What does Greek Philosophy have in common with the Sex Pistols and modular synthesizers?
At first glance, not a lot..... but delving into the MetroModular Boethian Wheel module it's worth considering this and the "Wheel of Fortune & of Fate"

The module takes it's name from the Roman/Greek Philosopher, Boethius (c. AD 475-525) who lived under the rule of the Ostrogothic Emperor Theodoric. Though most people won't have heard of Boethius, it was through him that translations of Aristotle survived. This alone should be enough to cement his name in history, however he is mainly remembered for one book.


His life began full of luxury and prestige. Boethius held high public office, but his life suffered a sudden reversal of fortune. He was imprisoned for the crime of treason (which he didn't commit). While awaiting the trial he wrote this book: The Consolation of Philosophy.


The book explores how evil can exist in a world with God. We today, often ask ourselves how can bad things happen to good people if there is a God? Though this link to Christianity is implied in the book, no reference to Jesus or the Church is made. Boethius doesn't ask God why this bad luck has befallen him. Instead, the book is a conversation between himself and "Lady Philosophy". They discuss the fleeting nature of wealth and fame ("no man can ever truly be secure until he has been forsaken by Fortune").

She teaches that happiness comes from within, and that virtue is all that one truly has.
On human nature, Boethius says that humans are essentially good and only when they give in to “wickedness” do they “sink to the level of being an animal.”

It's a really interesting book, written by a Christian who was also a Platonist. His morality and ethics lie within the Greek/Stoic tradition. I think this may be one of the very first "self help" books... and the fact that it was written in one year (AD 523) by a man in prison makes it all the more compelling a read.

And so what do the sex pistols have to do with Boethius?
The Sex Pistols , Joy Division, New Order , etc appear in the  2002 movie
"24 Hr People"

It's basically about Factory Records.
There is a famous quote about the Wheel of Fortune from the movie:


Dr Who ;-)
Christopher Eccleston

Some Links
+ Metromodular Facebook
+ Metromodular Youtube
+ Metromodular website  

+ + Philosophy index   

----------------------------
My Metromodular index page
--------------------------------- 

200e firmware upgrade procedures

My notes re this part of the 200e.
I've recently purchased a new 200e module so I need to update the firmware.

The current online manual relates to the 200e ver 30 firware upgrade.
 https://buchla.com/guides/Buchla_200e_v30_Upgrade_Guide.pdf
This was written when Version 30 was new (I think  about 2011/12).

There is an old V30 upgrade video in the links:
 https://www.youtube.com/watch?v=vxUU9bSR2ik
The page talks about having to load new boot-loaders (code-loaders) or even having to send the 206e or 225e to Buchla to have a new microcomputer installed.
Hopefully, your module isn't pre 2011 so you won't need to do this.
Anyway, in the video there are codeloader download links. These seem to have been removed
from the current website. All you have now are the utility & module firmware links.

My 225e is definitely post 2011.
Preset Managers containing the new micro-computers can be identified by the startup message "Primo Version"

Provided I have already installed a working codeloader (which I do)
I will now need to download a current Hex file from the Buchla website
The firmware page with downloads is here:
https://buchla.com/downloads/
Everytime a new module comes out it looks like it's necessary to upgrade the firmware on the 225e or 206e.
The manual states that I'll need a USB Firmware card and a Macintosh computer running OS 10.5 or higher. (I've tried to run the utility firmware on a PC unsuccessfully, so it looks like you must use a Mac).

The new module I've purchased is a 252e.
I've installed just the 225e & 252e in a separate system
When the system is turned on the 225e doesn't recognize the 225e.
On bootup the 225e preset manager says that just 1 module is in the system ..... I think this is the 225e USB/midi decoder.

So in order for the 225e to see the 252e it looks like I will need to download two pieces of software.
1. Firmware utility.  (BuchlaFirmwareUtility_171.zip)
2. The 206e/225e preset manager firmware..(225Sv323_Primo.hex.zip)

In order to load a hex file into the USB card:
A. Download the Zipped Firmware utility onto the Mac's desktop.
     BuchlaFirmwareUtility_171.zip
B. Open the Firmware utility on the Mac's desktop by clicking the zipped utility file. 


C. This will unzip the Firmware Utility. Save it onto the desktop. 
     The unzipped file has the pic of Don Buchla
D. Download the module's firmware hex file.(225Sv323_Primo.hex.zip)


E. Plug your USD card into the Mac.
F. Double-click the hex file’s icon in the Finder. (or drag and drop onto the firmware utility).
    The Firmware Utility application should launch and display info about the programming process.
    I am not a native Mac user, so found all kinds of obstacles.
    

I decided to override the computers security settings.

Once I had changed the security settings the Firmware Utility application launched.
I just dropped the hex file onto Don's image.  The Mac then displayed the expected info about the programming process.

While all this is happening watch the USB card. It's plugged into the Mac via a USB cable.


The LED on the card will flash to indicate it's being programmed.
Wait for all this to stop, then unplug the card from the computer..

G. Plug the USB card into the 200e card slot.

H. Turn on the 200e while holding down the "Load Button". Usually this is the remote 
     enable button.


You will see the LED on the card flash.

    Also the screen first looks like this:
     
But be patient. Programming seems to take a minute or two.
The screen changes to this:
Then this:
I did all this without any other 200e modules installed.

So the final test is to see if the 225e can now detect a new 252e.

Yes, success. :-)



I.   The 225e is really 2 modules : a Midi to CV converter & a presets section.   
     There are thus two separate hex files to download .. one for the Midi -CV & one for the
     Preset Manager.
     Version 32.3 (225Sv323_Primo.hex.zip) is required to recognize the latest set of modules
     including the 252e and h-series modules
     The 'data' button updates the preset M.  
     The 'remote enable' updates the midi to cv converter.

   
J.  Re the 281e
     This module has two identical CPUs.
     The 281e is actually a pair of modules. A-B and C-D are their own 'module'.
     The quadrature button for A-B updates the upper half & the quadrature button for D-D
     updates the lower half.
 K. Re the 285e frequency shifter
      View it as 2 separate modules... a frequency shifter and a balanced modulator.
      The Frequency Shifter uses  the 285F firware.
      The Balanced Modulator uses the 285B firmware
      Use the associated reference switches to update the firmware. (Reference source in both)

L.  Re the 206e
      The Mixer section uses the 206E firmware and is loaded by holding down the "remote enable".
      The preset manager uses the 225S firmware and is loaded by holding down "DATA". 
M.  Re the 223e
       The Arpeggiator uses the 223A firmware and is loaded by holding down "clock".
       The main section uses the 223M firmware and  is loaded by holding down "remote enable".

N.   Re. the 256e     
      This module has two identical CPUs.

       The first is loaded by holding down "Breakpoint in section A.
       The second is loaded by holding down  "Breakpoint in section C.



Links
+ 218e /225m & 208 card doubler firmware upgrade
+ buchla 200e firmware upgrade page
+ V30 upgrade video
+ ver 30 firware upgrade manual

Thursday, 6 June 2019

Metromodular buchla power supply - Todliche - build pics

These are my unofficial build pics for the metromodular buchla format power supply.

This PSU is installed in the Todliche Finger - Model 601
The psu can output 667mA on each of the +15 and -15 rails, and 1.5 A on the +5V rail, which should be enough for a 5-panel system.


 I don't have a BOM but if you buy the PCB, all the components are marked.

The name (Todliche) is a reference to the power supply board's edge connector “fingers”.


Its a very easy build
I'm sure Justin will be adding build notes to his website soon, if they haven't already been added.
















Some Links
+ Metromodular Facebook
+ Metromodular Youtube
+ Metromodular website  

----------------------------
My Metromodular index page
---------------------------------

Portabellabz VCS3 Card for 208

These are some pics taken during my build of the Portabellabz synthi/vcs3 card/
Its designed to be an expander for the Buchla 208 / Music Easel.
These are un-official notes and I'm not affiliated with Portabellabz.

The Official website is here:
+ http://www.portabellabz.be/vcs3.html 
+ Official Manual
+ Official Build notes
+ Muffs build thread

Resistors, IC sockets, Voltage regulators etc

Trim pots and caps.
The order of placement of my components isn't ideal. It was dictated by the components I had at hand and more were added as components arrived.

The rear so far.

More pots arrived :-)


This 2n5172 trannie is for the noise. Cut off the centre leg.
You need a to order a few of these so you can select the best one for the noise. (see build notes).

Some close ups .. esp of that 2n2916 and the 1K TC resistor



initial panel wiring

The noise transistor

There is one standoff missing .... between the freq and sync inputs.