This PCB attempts to replicate the Ensoniq writeable patch cartridges used by the ESQ-1 and SQ-80 synthesizer from the 1980s that used 64kb EEPROMs and stored 2 banks of 40 patches each. Both vintage cartridges and many modern, “upgraded” alternatives are selling for the same prices as many of these synthesizers themselves and a cheaper, more democratized option was required.

Designed with the AT28C64B in mind (28 pin DIP), it can be configured as a read-only or read/write cartridge. Instructions are on the PCB.

Optionally, the AT28C256 EEPROMs can be used with extra components at the top of the board and external switches to provide 4 original carts worth of storage (320 patches).

Latest PCB revision is available for purchase through Tindie: https://www.tindie.com/products/zensynth/oshdiy-ensoniq-esq-1sq-80-eeprom-cartridge/

And Reverb: https://reverb.com/item/62807297-ensoniq-esq-1-sq-80-eeprom-cartridge-pcb-direct-from-pcb-designer

Latest schematic designs along with CAD files for a 3D printed enclosure are now available on GitHub: https://github.com/JamesHagerman/Ensoniq-ESQ-1-EEPROM-Cartridge

A fixed version of my original 2014 LEGO RCX IR Tower mini Arduino shield. Write up of it’s use with `NQC (“Not Quite C”) can be found here: https://gist.github.com/JamesHagerman/24f350ff177bf9bf80a440e7e5e4f525

Note: This version is untested, but it’s simple enough that I’m 90% certain it will work as expected.

An untested upload of sytse’s Gerber files for their CYC1000 shim for use with the PiDP11 . More info can be found at https://pdp2011.sytse.net/wordpress/shim-design-2/#comments

3.12" OLED Featherwing

This Featherwing interfaces with a relatively unknown 3.12" OLED grayscale SSD1322-based screen I found somewhere on AliExpress. The one I have is this really awesome yellow color that I just can’t stop looking at.

The screen supports 4 different modes but this board was designed for use with it’s 4SPI mode. This board duplicates the screen’s header to make other development easier. I didn’t fully follow the datasheets on what pins to ground in 4SPI mode but my initial tests showed that didn’t really matter anyways.

The screen is just a little too small to fit two featherwings in the same footprint. One will always hang off the edge. But I threw it on there anyways because you can never have enough featherwing headers!

PCM5102 I2S Header

Because of all the extra space, I also threw on a header for the cheap PCM5102 I2S breakout board. I haven’t seen any solid I2S Featherwings so this should be a good shoehorn to give the world as well.

The DMA and I2S portion of Suda’s Particle-powered ps-01 Software Synthesizer can send audio to this I2S DAC pretty easily. I’ve been meaning to port the DCO-based audio tracker I demo’d at LayerOne in 2017 to a Particle Argon and this will make that easier to do.

A3144 Hall Effect Switch Header

The board also provides a place to attach the A3144 Hall Effect switch along with the required pull up resistor. These pins are hooked up to the 3.3v line because testing showed them working okay below their spec of 4.5v.

I haven’t seen any Featherwings that break out a Hall effect switch and it’s really easy to use them for odometers/spedometers given some math and a pile of magnets. It was easy enough to drop on the board so there we go.

p9813 LED power distribution board