MIPI DSI, LVDS and RGB are the three interfaces you will meet most often when choosing an embedded display. The interface decides which host processors can drive the panel, how far the display can sit from the board, how much cabling you need and how much driver work is involved. It is also the hardest display decision to undo: an interface mismatch found late usually means a PCB respin.
Quick comparison
| Interface | Typical resolution | Signals | Typical use | Driver complexity |
|---|---|---|---|---|
| Parallel RGB | Up to WXGA (1280 × 800) | 20 to 40 wires | Mid-size panels, FPGAs and DSPs | Medium |
| LVDS, single channel | Up to XGA (1024 × 768) | 4 differential pairs + clock | Industrial panels, fanless PCs | Low to medium |
| LVDS, dual channel | Up to WUXGA (1920 × 1200) | 8 differential pairs + clock | High-resolution industrial and medical | Medium |
| MIPI DSI, 1 lane | Up to 720p | 1 differential pair + clock | Mobile, wearables | Medium to high |
| MIPI DSI, 4 lanes | Up to 4K | 4 differential pairs + clock | Tablets, embedded computing | High |
MIPI DSI
MIPI DSI is the dominant interface for compact, high-resolution displays. Its low pin count and high bandwidth suit small, dense designs, but it puts real demands on the host:
- The host SoC’s lane count and maximum lane speed must match the panel datasheet.
- Video mode and command mode both exist; confirm your processor’s MIPI block supports the mode the panel uses.
- The panel’s initialization sequence must be implemented in firmware, and it should come from the panel maker. Generic sequences often fail.
- Trace length to the display connector is typically limited to about 100 to 150 mm at high lane rates.
- On Linux, check that a panel driver already exists in the kernel. Writing a new one adds one to three weeks.
LVDS
LVDS remains the workhorse of industrial and medical displays because of its noise immunity, longer cable reach and large range of industrial-grade panels.
- Panels use either the VESA or JEIDA bit mapping. A mismatch with the host gives scrambled colors.
- LVDS needs 100 Ω differential termination at the receiver; check whether the panel includes it.
- Cable runs of 1 to 2 m are achievable with careful design. Beyond that, consider serialized links such as FPD-Link III.
- LVDS panels are widely available with industrial temperature ratings and long production lives, which suits products with 10-year lifetimes.
Parallel RGB
RGB sends pixel data on a wide parallel bus. It is simple to drive from FPGAs, DSPs and many microcontrollers with a display controller, and needs little driver work. The trade-offs are pin count (20 to 40 signals), short cable reach and more EMI, so RGB panels are best kept close to the board and are most common at small and mid sizes.
How to choose
- Start with the host processor. Use an interface it supports natively before considering bridge chips.
- Consider the distance. Display close to the board and small: RGB or MIPI DSI. Display farther away, larger or in an electrically noisy machine: LVDS.
- Think about second sources. Widely used interfaces such as LVDS have many compatible panels, which makes it easier to replace a panel later.
- Decide before PCB layout. Lock the interface before routing the host processor.
Browse MIPI DSI displays, LVDS displays and RGB and TTL displays, and get the full details in The Engineer’s Checklist for Choosing Embedded Displays and The Engineer’s Guide to MIPI DSI Integration.
About DCL Technologies
DCL designs high quality display solutions that meet our clients’ overall objectives.
Our mission is to be the easiest display solution provider to do business with.
Our differentiator is a focus on delivering the best experience to our clients, at every desk. Our core value strategies are focused on making it easy for Engineers, Designers and Purchasing to get things done.
Contact:
Andrew Blum
DCL Technologies
800-407-8917
ablum@dcltek.com
www.dcltek.com
