Build Diary #5: Advanced Yarns

Blue Lantern Advanced Yarns. Sounds pretty neat right? BUT FIRST.

No more long winded posts! Just some spicy PCB shots and things that might be helpful to others… for the most part.

Because I recently grabbed a Digitakt, I now need something to take advantage of these sweet sweet MIDI tracks in the Eurorack world. Enter Yarns. 

I tried to get mBrane.. the tiny little Yarns, but Pusherman only had a single PCB left. I decided to go with Advanced Yarns instead. BUT GET THIS. In my package from Pusherman they included the single mBrane PCB for free. What a sweet pea that Pusherman/Phil is. Thanks a bunch, if you ever read this.

Core PCB Complete Yarns
Soldered and flashed up

First, I’ll start with the Core PCB. Tt seems like the four 10u caps used here are 1206 footprint, although the BOM reads 0805. Because 0805 fit just fine it doesn’t bother me, but if you’ve got PCB OCD, don’t make that mistake.

Also, here are the parts that aren't labeled.

Second, let’s talk software. Flashing this guy was a journey. Mostly because I had to try a few different computers before I got it going . This was the process I ended up using.

  1. Get the core PCB built (or at least the MCU, power sections, as well as the two push buttons).
  2. Check jumper placement, set to flash by having the single jumper on “BT”. In the above shot the board has been flashed and the jumpers have been moved from the flashing position.
  3. Grab an FTDI dongle, most places recommend FTDI Friend, I grabbed this FTDI Dongle
  4. Connect Euro power, connect TX, RX and Ground pins with FTDI dongle. (RX and TX need to speak to each other, so remember to connect: TX on FTDI dongle to RX on PCB, and RX on FTDI dongle to TX on PCB)
  5. Start mutable dev environment
  6. Navigate to “eurorack-modules”, then “stmlib”, and change the PGM_SERIAL_PORT ?= variable to PGM_SERIAL_PORT ?= /dev/ttyUSB0
  7. Compile the bootloader and firmware:
    make -f yarns/bootloader/makefile hex
    make -f yarns/makefile
  8. On the PCB, prepare the chip for flashing. Press the “R” button for 1 second. Let go, press and hold the “R” and “F” buttons for 3 seconds. Let go of the “R” button and hold the “F” button for 5 seconds.
  9. Flash using the following command:
    make -f yarns/makefile upload_combo_serial
  10. If you receive any “can’t INIT” messages, try from step 8 over again. The chip may not have received the “time to flash” message from the button presses.
Controller PCB Finished

And third, as far as the controller PCB goes, what a little trip this was. I’m starting to understand why this thing is an “Advanced” Yarns. I was looking for the ground on the CV/Gate jacks, as well as the 2 trigger jacks… and I could not find them. Turns out, the panel grounds these jacks through the sleeve.  I am not sure if it is visible in the picture, but the panel has a route to ground from these jacks. I snipped the ground legs then soldered like normal.

Don't pay attention to the jack orientation here! I goofed up good

The above picture shows the jacks all in, but all in… backwards. Because I misread the PCB , I ended up having to pull out all 10 top jacks… that was NOT the best time. But boy was I happy when the CV jacks started CV’ing!

Completed Yarns Module
Preeeetty neat.

And finally, that’s it! Advanced Yarns! It is hooked into the Digitakt and I can’t wait to spend the next couple days learning how it works. Very gnarly module.

Maybe I’ll start doing something with a slightly larger demographic…Audio plugin reviews? I just want internet attention is all. Also, I am shocked I’m not winning Pulitzer’s over these Advanced Yarns’.

Quick Links

Mouser BOM – No jacks, no LEDs, no hardware (standoffs, screws)

Blue Lantern build docs

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