HDMI Detailed introduction-Pins Definition

HDMI Detailed introduction – Pins Definition

HDMI, better known as High Definition Multimedia Interface, is mainly used for transmitting high definition audio and video signals.

HDMI greatly simplifies wiring by delivering high definition, all digital audio and video content over a single cable, providing consumers with the highest quality home theater experience.

Key features of HDMI :

● The ability to transmit uncompressed HD video and audio signals.

● Plug-and-play. 

● Simultaneous transmission of audio and video signals.

● Digital Content Protection (HDCP).

HDMI pinout :

Standard HDMI interface pinout diagram (Receptacle)

HDMI has five types of pins A,B,C,D,E. Currently, the more common ones on the market are Type A as below figure.

Among these 19 Pins : 

• - 1-9 are the pins actually used for TMDS data transmission, divided into three groups of 0,1,2.
• - 10-12 for the TMDS clock signal, such as the current Video Timing for 480p@60Hz (Htotal: 800, Vtotal: 525), then TMDS clock = 800x525x60 = 25.2MHz. TMDS clock is like a packing of pixels, a clock in three Channels to transmit a pixel of R, G, B (8bit) signal respectively.
• - 13 for CEC (consumer electronic control) is similar to an extended HDMI function for manufacturers to customize their own HDMI messages.
• - 14 is a reserved pin, not used (or can also provide an additional pin for CEC)
• - 15-16 are I2C pins, used for DDC (Display Data Channel, mainly for EDID and HDCP transmission) transmission.
• - 17 is the ground pin.
• - 18 is the AC pin for 5v.
• - 19 for Hotplug (Hotplug) pin, used to monitor the presence of HDMI devices, if there is a device (Hotplug is high) EDID can be read through the DDC.

Standard HDMI interface male pinout and definition diagram

Standard HDMI male connectors are welded schematically as follows, and are welded one by one according to the same number.

HDMI circuit diagram of Type-A :

HDMI Types

In addition to the common Type A mentioned above, there are four types of HDMI interfaces: Type B, Type C, Type D, and Type E. Reference can be made to the following chart.

• 1, HDMI A Type is the most widely used HDMI cable, HDMI A interface with a total of 19 pins, 13.9 mm wide and 4.45 mm thick. The vast majority of audio and video equipment in daily use are equipped with this interface. For example: Blu-ray players, Xiaomi boxes, laptops, LCD TVs, projectors and so on.
• 2, HDMI B Type is less common in life, it is mainly used for professional-grade occasions. HDMI B interface uses 29 pins, width 21 mm. HDMI B Type's data transmission capacity is nearly twice faster than HDMI A type, equivalent to DVI Dual-Link. Since most audio and video devices operate at less than 165MHz, HDMI B Type operates at more than 270MHz, so it is mostly used in professional application scenarios, such as WQXGA 2560×1600 or higher resolution.
• 3, HDMI C Type is often referred to as Mini HDMI, it is mainly designed for small devices. HDMI C Type also uses 19 pins, but the width is only 10.42mm and the thickness is 2.4mm. It is mainly used in portable devices, such as digital cameras, portable players and other devices.
• 4, HDMI D Type commonly known as Micro HDMI. HDMI D Type size further reduced. It is also 19 pins, only 6.4 mm wide and 2.8 mm thick, much like a Mini USB port. Mainly used in small mobile devices above. For example: cell phones, tablet PCs, etc.
• 5, HDMI E Type is mainly used for audio and video transmission of in-car entertainment systems. Due to the instability of the in-car environment, HDMI E Type is designed with characteristics such as shock resistance, moisture resistance, high strength resistance, and a wide range of temperature difference tolerance. In the physical structure, the mechanical locking design is used to ensure contact reliability.

By HornmicLink_Henry @221205 17:58