SPI display demo

The repository's SPI lesson drives an ST7789 display from an RDK X5. The runnable code lives in 01_beginner/13_40pin_spi.

What the demo covers

• SPI clock, MOSI, and chip-select signals
• GPIO control for data/command, reset, and backlight
• Enabling and checking the SPI device node
• A static display test followed by a simple animation

Open the course directory README for the wiring table, dependencies, commands, and troubleshooting notes.