The LCD controller that drives the display of the Pinetime is the [Sitronix ST7789V](https://wiki.pine64.org/images/5/54/ST7789V_v1.6.pdf). This controller is easy to integrate with an MCU thanks to its SPI interface, and has some interesting features like:
When you want to write a device driver for a specific component, its datasheet is your holy bible. This document contains a lot of information about the chip, its specification, characteristics, features and functionalities.
As I said in the introduction, the datasheet will be your bedside book during your journey as a device driver designer. You'll read it from the beginning to the end once, twice, maybe ten times. Then, each time you'll want to do something new, you'll reopen the file and search for that specific paragraph or diagram than explains how the controller works so that you can figure out how to use it.
The schematic of your board (the Pinetime schematics in this case) will also be very important, as you'll need to know how the LCD controller is physically connected to the MCU.
How to read the datasheet? I recommend to read it from the beginning to the end (no joke) at least once. You certainly do not need to read everything in details, but it's good to know what information is available and where in the document. It'll be very useful during the development phase.
