--- title: Display and Camera Interfaces url: https://doc.liz6.com/en/hardware/06-interfaces-and-communication/05-display-and-camera-interfaces locale: en area: hardware tags: - hardware - interfaces-and-communication date: 2026-06-30 modified: 2026-07-16 description: 'Display and Camera Interfaces Interface Overview Interface Overview: Signal Connections Between Chip and Screen/Camera Chip Internal → Screen MCU/MPU MIPI DSI L…' --- # Display and Camera Interfaces ## Interface Overview --- ## HDMI (External Monitor) ### Version Evolution ``` HDMI 1.4: 4K@30Hz, 10.2 Gbps HDMI 2.0: 4K@60Hz, 18 Gbps, HDR HDMI 2.1: 8K@60Hz/4K@120Hz, 48 Gbps, VRR/ALLM Note: The HDMI 2.1 standard has deprecated the term "HDMI 2.0". HDMI 2.0 is now considered a subset of HDMI 2.1. Therefore, ask: "Does it support 48Gbps and VRR?" rather than just checking the version number. ``` ### Electrical ``` TMDS (HDMI 1.4/2.0): 3 data channels + 1 clock channel FRL (HDMI 2.1): 4 data channels (Fixed Rate Link), up to 12Gbps per channel Differential 100Ω, AC coupled DDC (I2C over HDMI): EDID to read monitor capabilities CEC: Consumer Electronics Control (one remote controls multiple devices) HPD: Hot Plug Detect ``` --- ## DisplayPort (External/Built-in) ### Versions ``` DP 1.2: 4K@60Hz, 21.6 Gbps DP 1.4: 8K@60Hz (DSC compression), 32.4 Gbps, HDR DP 2.0: 16K@60Hz (DSC), 80 Gbps (UHBR20) DP 2.1: Same bandwidth as 2.0, specification improvements UHBR (Ultra High Bit Rate): UHBR10: 10 Gbps/lane × 4 = 40 Gbps UHBR13.5: 13.5 × 4 = 54 Gbps UHBR20: 20 × 4 = 80 Gbps ``` ### Comparison with HDMI | Feature | HDMI | DisplayPort | |------|------|-------------| | Positioning | Consumer Electronics (TVs/Projectors) | PC Mainstream | | Multi-Stream | ❌ | ✅ MST (Multi-Stream Transport / Daisy Chain) | | Adaptive Sync | HDMI 2.1 VRR | DP 1.2a+ Adaptive-Sync | | USB Type-C | Alt Mode | Alt Mode (More Popular) | | Max Bandwidth | 48 Gbps (2.1) | 80 Gbps (2.1 UHBR20) | | Licensing Fee | Yes | Free | ### eDP (Embedded DP) ``` Laptop built-in screen interface Based on DP protocol, with reduced power consumption and EMI v1.4/v1.5 support 4K@120Hz internal screens Typically 1~4 lanes ``` --- ## MIPI (Mobile/Embedded Mainstream) ### Why MIPI ``` LVDS/HDMI consume too much power → Mobile/embedded devices need low-power solutions The MIPI Alliance defines a series of interface standards for mobile devices Two main display/camera interfaces: DSI (Display Serial Interface): Chip → Screen CSI (Camera Serial Interface): Camera → Chip ``` ### D-PHY vs C-PHY ``` D-PHY: Differential clock + 1~4 pairs of differential data Per lane: Up to ~4.5 Gbps (v2.5) Common: 2-lane or 4-lane C-PHY: 3-phase encoding (3 wires transmit 2.28 bits/symbol) Per lane: Up to ~6 Gsps Fewer pins but more complex ``` ### MIPI DSI ``` Typical Connection: MPU ── DSI (2-lane or 4-lane) ──→ LCD/OLED Panel DSI Command Mode: Similar to SPI, the screen has its own frame buffer Suitable for static/low refresh rate content DSI Video Mode: Continuous screen refresh, no frame buffer Suitable for animations/video Resolution Range: 480p (1-lane) ~ 4K (4-lane D-PHY v2.0+) ``` ### MIPI CSI ``` Typical Connection: Camera Sensor ── CSI (2/4 lane) ──→ ISP/MPU Usually unidirectional (Sensor → Host) Independent clock recovery per lane (DDR sampling) Common Configurations: 1080p@60fps: 2-lane 4K@30fps: 4-lane (or 2-lane × 2) 4K@60fps: 4-lane C-PHY or higher frequency D-PHY CSI-2 also supports virtual channels: Multiple cameras sharing the same CSI bus ``` --- ## Other Display Interfaces ### RGB (MCU Screen / 8080/6800 Parallel) ``` Legacy/Low-resolution screen interface 8/16 data lines + Read/Write, Chip Select, Command/Data Select Parallel data → Many wires, speed limited (Fmax ~30MHz) Used for: Small screens (< 480×320), industrial screens, low-cost products ``` ### LVDS (Marginalized) ``` Legacy interface for laptop internal screens, being replaced by eDP 4 pairs of differential data + 1 pair of differential clock Typical: Single-link 1366×768, Dual-link 1920×1080 ``` ### VGA (Analog, Obsolete) ``` R/G/B analog signals + H-Sync/V-Sync 15-pin D-Sub Low bandwidth, signal quality degrades with cable length ``` --- ## Quick Selection Guide ``` Scenario Recommendation ──────────────────────────────────── External Monitor (PC/Laptop) DP > HDMI TV/Projector HDMI Laptop Internal Screen eDP Mobile/Embedded Screen MIPI DSI Camera Module MIPI CSI Raspberry Pi/ARM Dev Board MIPI DSI/CSI or HDMI Small/Low-Resolution SPI/RGB (MCU Screen) ``` --- *Keywords: HDMI, DisplayPort, eDP, MIPI, DSI, CSI, D-PHY, C-PHY, TMDS, DSC, EDID*