Designing this board took considerably more time than I anticipated. I thought I was in a good starting place by having two reference designs from previous projects that repurposed Amazon Kindle displays and controlled them with an ESP32, Inkplate 6 and EPDiy.
My first hurdle was after realizing that both reference designs make use of various discontinued or “obsolete” components. My initial instinct was to locate these chips, such as the TPS65186, from one of the less familiar suppliers on Octopart. After some fruitless back and forth with Win Source Electronics I was able to locate another chip, the TPS65185, that IS actively being produced with what appears to be similar enough functionality.
The last week has been a series of these kind of struggles, looking for similar enough components as I rebuild the board functionality in my own Eagle project.
After much labor here is the schematic.
The board makes use of an ESP32 WROVER module as well as an I/O Expander to accommodate the many data lines needed to control the EINK display.
I had initially hoped to use an ESP32 S2 mini because of the integrated USB functionality but the reference designs both make use of a WROVER module and remapping the pinout proved exceedingly difficult.