I wanted to add a small OLED without having its headers determine the height of the whole assembly. Castellated pads let this module solder directly onto a custom PCB, keeping the display closer to the board.

The pads retain a standard 2.54mm pitch, so headers remain an option during prototyping. That gives the same module a route from a bench experiment to a lower-profile installation.

The module has a 0.9-inch monochrome white display with 128 × 64 pixels, an SSD1315 controller and I²C. I’ve linked the wiring and library information for bringing up a readout or menu.

Documentation: https://www.questwiseventures.com/products/castellated-0-96-in-oled-ssd1315-i2c-128x64-screen