AR Display Dev. Board

Development board layout and bring up for a client to demonstrate functionality of display and IO system.

PCB Features:

8-Layer Board with impedance matched signaling
7 Power Rails
High Speed Signaling: MIPI, LVDS, USB 3.0

Bringup:

Debugging and validation of display system.
Firmware for System Microcontroller
- USB-C PD, Power profile management and selection
- USB-C DP-ALT, USB-C port orientation configuration
- Remote backlight driver control over I2C
- Backlight adjustment signal from user application microcontroller
Base firmware and libraries for user application microcontroller

Layout

The system schematic was a compilation from several reference designs. I had validated subsystems of the design with previous faulty hardware. Board layout performed in EasyEDA per client requirements. Tool limitations required hand matching differential signal trace lengths and spacing. PCB impedance matching calculations done using Saturn PCB Toolkit.

Troubleshooting and Validation

Debugged and validated each independent subsystem of the development board, identifying missing or required replacement of components and connections. Made temporary fixes to ensure functionality of changes. AR optic seen in lower right of adjacent image.

Developed Firmware and Demonstrated Functionality

Developed the Firmware for the main system microcontroller and validated its functionality. Demonstrated functionality of the display path as well as other user application specific interfaces:

User Application Microcontroller
USB 2.0 + USB 3.0 Hub
User GPIO including backlight control