What is UART in HDMI?

UART in HDMI stands for Universal Asynchronous Receiver/Transmitter. It's a communication protocol used within the HDMI (High-Definition Multimedia Interface) standard for specific purposes. Here are some key points about UART in HDMI:

1. Purpose: UART is primarily used for the Consumer Electronics Control (CEC) feature in HDMI.

2. CEC Function: CEC allows users to control multiple HDMI-connected devices with a single remote control, enabling features like one-touch play or system standby.

3. Low-Speed Communication: UART provides a simple, low-speed serial communication method between HDMI devices.

4. Bidirectional: It allows for two-way communication between connected devices.

5. Asynchronous: UART doesn't require a shared clock signal between devices, making it simpler to implement.

6. Single-wire Implementation: In HDMI, the UART for CEC typically uses a single wire for bidirectional communication.

7. Standardization: The use of UART for CEC is part of the HDMI standard, ensuring compatibility across different manufacturers' devices.

8. Low Overhead: UART's simplicity makes it suitable for the basic control functions needed in CEC without adding significant complexity to HDMI implementations.

While HDMI is primarily known for its high-speed digital video and audio transmission capabilities, the inclusion of UART for CEC adds an important control and interoperability feature to the standard.