You'd need to mount the Axolotl the other way round, and the module would be way too wide, with the MIDI part as well.
Paul is designing an expander module to break out the MIDI in and out ports, the micro USB programming socket, and 2x CV outputs.
a|x
Moved discussion about the MAX11300 adc/dac chip into a separate thread here: https://sebiik.github.io/community.axoloti.com.backup/t/max11300-for-cv-out-and-cv-out/1568
Further to the questions I asked in the wrong place (doh) https://sebiik.github.io/community.axoloti.com.backup/t/euxoloti-hardware-version-confusion/1667 will the new pcbs still be open source?
hi everyone, as I posted in an other thread, the new proto boards have arrived…after assembling everything, beside button reading (done by a 74hc165) where I have forgotten an tristate buffer to block miso message while reading other ICs, worked…but now I got stocked. my adc don't read the right values and jumping. I also have a conflicts with different spi clock req. rate. Some source on the internet wrote that this a clear sign for spi error…
VDD is stable at 3,31V and adc channel 0-6 is stable at 1,647V. So dial position should be around 32.75…
I have tried three different pairs of mcp6004 op amps and mcp3208.
I also connected a brand new mcp3208 to axo and a breadboard and recorded axo<->adc spi communication by logic sniffer.
maximum analog<->digital ground resistance is not higher then 0,1Ω...
1. test round
ADC CH0 = VDD = Axoloti hex object: 0x87FF0000
test round
ADC CH0 = 1,647V = Axoloti hex object: 0x83D40000 or 0x83E40000
test round
ADC CH0 = GND = Axoloti hex object: 0x00800000
I got the same results with adc on breadboard and axoloti only.
Does anyone have any suggestions to solve this problem?
current prototype revision schmeatic
update spi debug session.
OK, I think I know what's going wrong at SPI. it's a problem of clock cycle length and transmitting datas on MISO.
the main core + control pcb works
but if some other ICs are added to the spi bus, I got odd value from ADC.
It seems that the adc value are shifted by 1 bit while transmit session on MISO line.
What I have done since now:
checked VDD (axoloti, mcp3208, mcp6004) by oscilloscope and it's stable while powering from eurorack psu (Axo 5V = 4,98V and axo VDD is 3,31V). If euxo core pcb and axoloti is only powered by usb, axoloti monitor shows red voltage values (4,73V) for 5V line but now voltage drop outs or disconnections. VDD stays stable at 3,21V.
no shorting between communication lines or VDD and GND.
In last revision the adcs and op amps are powered by an external 3,3V vreg and Vref of each ADC (AVDD) is connected to VDD and its filtered by a 10Ω resistor. Pots are also connected to AVDD. I also disconnected ICs' VDD from ext. vreg and connected them to axo VDD vreg.
traceroute length MOSI = 101,7mm; MISO = 98,35mm; SCLK = 110,39mm; CS1(ADC 1/cv ins) = 65,57mm; CS2(ADC2/Pots) = 88,29mm
eagle files
measured resistance of several different points(VDD,AGND-GND, AXO GND-EURORACK, SPI IC-AXO etc.) and it's at max. 0,1Ω(tool has a tolerance of 0,1% 
)
checked spi message by bus pirate and logic sniffer at IC socket of both mcp3208 and directly at the breakout row next to the axoloti core header row. no problems, some longer cycles are recorded ( check post before) and axoloti stops to receive correct adc values.
Setup different ICs for SPI communication on a new breadboard …same but after a while axoloti shuts down like there is a shorting or something consumes more power then axo can deliver. breadboard ICs are powered by axo's VDD.
tried axoloti 1.0.6 and axoloti 1.0.10; and different Macs.
tested different SPI modes and clock speed. no problem with euxo core adcs at SPI only. same with connected control pcb.
tried 4 different type pairs of ICs.
tested previous euxo prototype and this one works out of the box with more ICs on SPI bus.
So does anybody know, what's the cause for the spi (clock) problem? I don't know how to fix this problem.
Edit:
here are axo patch and my script2 object code for reading pots and cv ins:
euxo cv&pot read
script2 object code
Hi!
This is a very interesting project. It would be fantastic to use the Axoloti in a Eurorack system!
Is this project still active?
How are the already owners working with the Euxoloti? How is the experience?
Will it be posible to order an Euxoloti already mounted in the future?
Thanks!
Hi Everyone,
Does anyone know what the status of Euxoliti is? I've seen the Euxoloti site still says new boards will be printed March 2017... but he hasn't posted here since last August, Hasn't tweeted since October, and hasn't commited anything on Github since February. Has anyone heard from Paul?
hey , i build two versions of euxoloti and i can say Paul's a friend but the project needs a serious update there is still no correct v/octave
i wish more people get involved or maybe helping out the problem would be awesome !!!
Okay, in that case maybe I'll have to break down and buy a few pcbs on OSH park... unless someone already has some lying around? 
Last I heard, Paul had been having persistent internet-connection problems, and was therefore effectively offline, much of the time.
I imagine this has been hampering his ability to continue with the project (though, knowing Paul, in pretty sure he's been keeping busy with some interesting project or other).
Hopefully we will all hear from him again soon.
a|x
Oh boy. I'd love to see this project come to fruition. I've been following it once in a while for a few years now. It would be the mostly friendly and community supported programmable module to date.
What can we do to get this going again?
If anyone is interested i´d like to sell my build. It is the latest version and fully working except the gate8 expansion.
Sold as is (in need of completion) to the expierienced DIYer
I´d ship worldwide. just send me a pm if interrested
The Euxoloti is know sold!!!!!!!!!!!!!!!!!!!!!!!
I went the lazy way myself. I'm making a Eurorack module out of mine with all the analog and digital control inputs wired to pots and switches. For CV control, I bought a doepfer a-192 voltage-to-midi interface module (though discontinued, Analog Haven still has some) which provides 16 CV ins. I will probably mount them both in the same panel. With that setup, although maybe not as elegant as a custom interface made for the Axoloti, you still have no worries of overloading the CV in on the Axoloti and have PLENTY of controls to play with if your patch needs it. I thought of dedicating some of the digital I/O lines into being gate outs with a simple transistor circuit, but that and the front panel (Front Panel Express) would be the only custom parts.
I spoke to a number of people at Knobcon about this project. If none of them are going to bite, we're going to add a Eurorack solution for Axoloti so people can buy finished modules / kits.
If you would like an established company to sell through, Synthwerks would be interested in looking at what you come up with. Only if you don't want to deal with the hassles of manufacturing yourselves. If you do decide to make product yourselves, think of a through-hole version for the kit (if it is not too complicated). You will sell more of them than a SMD version. Of course you can make a "Smart kit" that was a tested SMD PCB with the user adding just the through hole connectors and switches. There are plenty of web stores that specialize in kit versions and DIY versions of modules that would probably love to sell some.
To be honest, after realising that there was not much progress on the euxoloti recently (so it seemed to me, at least) I was almost considering to roll my own open hardware Axoloti-eurorack integration module. That's how much I'm waiting for this to happen. But to be realistic, I won't have the time to do it right now. So if this project is moving forward, consider me one of the first to build it.
