This code is currently under development, and is not ready to be used yet. See the TODO section
The Gjallarhorn Sleipner is an open source Eurorack compatible step sequencer. Powered by an Atmel AVR ATmega32 running at 16 MHz, it features 2 CV/gate channels and 6 gate only channels for controlling percussion or similar.
The firmware may be built by simply running
make
Once the firmware main.hex is built, upload it to the MCU and set the correct fuse bits. The example below uses
avrdude on a Raspberry Pi to program the MCU (make sure that your avrdude.conf is setup correctly according to the
pins being used)
avrdude -c linuxgpio -p atmega32 -v -U flash:w:main.hex
avrdude -c linuxgpio -p atmega32 -v -U hfuse:w:0xC9:m
avrdude -c linuxgpio -p atmega32 -v -U lfuse:w:0xEF:m
Please note that you will have to connect a 16 MHz crystal to the ATmega32 in order to use it once the fuses have been programmed.
All eight gate outputs are 12 V with an output impedance of roughly 470 ohm.
The clock output is 5 V. Just like the gates, its output impedance is roughly 470 ohm.
The two CV outputs are 0 V - 10 V and follows the 1 V per octave standard. A C4 note corresponds to 4 V.
TODO
The list below is far from an exhaustive list of what's coming, but the main features for a 1.0.0 version should all be listed.
- Documentation: Write a usage and improve the technical specs section
- Firmware: Read the input state of the two command buttons, fé and úr
- Firmware: Allow a user to change the channel, tempo and note of the CV channels
- Firmware: Allow a user to set gate duration as a percentage of a step
TODO once version 1.0.0 has been achieved.