HDMI Interface
HDMI (High-Definition Multimedia Interface) is a digital audio/video transmission interface that carries image and audio signals from a host device (such as a Raspberry Pi, PC, or Jetson) to a display over high-speed differential signaling.
Key characteristics:
- High bandwidth: supports resolutions from 720p up to 4K and beyond
- Audio + video in one cable: transmits both audio and video simultaneously
- Plug-and-play: uses EDID to automatically negotiate display parameters
- Wide compatibility: works with PCs, Raspberry Pi, industrial controllers, and more
- HDMI relies on EDID for resolution negotiation; automatic matching is not guaranteed in all scenarios
- Cable quality, length, and interference can affect display stability
- Some hosts require manual resolution configuration or forced-output mode
Interface Types
Common HDMI connector types:
| Type | Name | Typical Devices | Notes |
|---|---|---|---|
| Type A | Standard HDMI | PC, monitor, development board | Full-size |
| Type C | Mini HDMI | Embedded devices | Compact size |
| Type D | Micro HDMI | Raspberry Pi, etc. | Ultra-compact |
Pin Definition
The following describes the pin layout and function of a standard HDMI Type A (19-pin) connector.
HDMI Type A uses a 19-pin design with alternating odd/even rows to support TMDS differential signal transmission and control channels.
| Pin | Definition | Pin | Definition |
|---|---|---|---|
| 1 | TMDS Data2+ | 11 | TMDS Clock Shield |
| 2 | TMDS Data2 Shield | 12 | TMDS Clock- |
| 3 | TMDS Data2- | 13 | CEC |
| 4 | TMDS Data1+ | 14 | Reserved |
| 5 | TMDS Data1 Shield | 15 | DDC Clock (SCL) |
| 6 | TMDS Data1- | 16 | DDC Data (SDA) |
| 7 | TMDS Data0+ | 17 | DDC / CEC Ground |
| 8 | TMDS Data0 Shield | 18 | +5V Power |
| 9 | TMDS Data0- | 19 | Hot Plug Detect |
| 10 | TMDS Clock+ | — | — |
HDMI Type A, C, and D are electrically identical; they differ only in physical connector size and pin arrangement.
Raspberry Pi HDMI Interface
Different Raspberry Pi models use different HDMI connector types:
| Model | Ports | Connector | Max Single-Screen | Dual-Screen |
|---|---|---|---|---|
| Pi Zero / Zero 2 W | 1 | Mini HDMI (Type C) | 1080p @ 60Hz | Not supported |
| Pi 1 / 2 / 3 | 1 | Standard HDMI (Type A) | 1080p @ 60Hz | Not supported |
| Pi 4 | 2 | Micro HDMI (Type D) | 4K @ 60Hz | Dual 4K @ 60Hz |
| Pi 5 | 2 | Micro HDMI (Type D) | 4K @ 60Hz | Dual independent outputs |
- Output resolution is negotiated between the host GPU and the display's EDID. If automatic negotiation fails, configure the resolution manually.
- HDMI supports hot-plug detection (HPD). If no display is detected at boot, the host may not output a signal — try re-plugging the HDMI cable.
Safety Precautions
To avoid damage to the product, observe the following:
- Power off your Raspberry Pi and disconnect external power before connecting any cables.
- If a cable becomes disconnected, pull the connector latch forward, insert the ribbon cable with the metal contacts facing the correct direction, then push the latch back.
- Do not fold or strain ribbon cables.
- Take care when fastening screws. Cross-threading can cause irreparable damage and voids the warranty.
- Operate the device in a dry environment between 0–60°C. Do not expose to water, moisture, or conductive surfaces.
- Do not expose to excessive heat. Store in a cool, dry place and avoid sudden temperature changes.
- Handle with care to avoid mechanical or electrical damage to the PCB and connectors. The display surface is fragile and may crack if subjected to impact.