• HDMI Made Easy: HDMI-to-VGA and VGA-to-HDMI Converters The consumer market has adopted High-Definition Multimedia Interface (HDMI ®) technology in TVs, projectors, and other multimedia devices, making HDMI a globally recognized interface that will soon be required in all multimedia devices. Already popular in home entertainment, HDMI interfaces are becoming increasingly prevalent in portable devices and automotive infotainment systems. Implementation of a standardized multimedia interface was driven by a highly competitive consumer market where time to market is a critical factor. In addition to improved market acceptance, using a standard interface greatly improves compatibility between projectors, DVD players, HDTVs, and other equipment produced by various manufacturers.

In some industrial applications, however, the transition from analog video to digital video is taking longer than in the consumer market, and many devices have not yet moved to the new digital approach of sending integrated video, audio, and data. These devices still use analog signaling as their only means of transmitting video, possibly due to specific requirements of a particular market or application. For example, some customers still prefer to use video graphics array (VGA) cables for projectors, while others use an audio/video receiver (AVR) or media box as a hub, connecting a single HDMI cable to the TV instead of a batch of unaesthetic cables, as outlined in Figure 1. Media box converts analog signal to HDMI. New adopters may see HDMI as a relatively complicated standard to implement, requiring a validated software driver, interoperability checks, and compliance testing to guarantee proper behavior of one device with various other devices.

This might seem a bit overwhelming—as is often the case with new technology. However, advanced silicon solutions are increasingly available to tackle the problem of implementation complexity, achieving improvement in both analog and digital domains; they include higher performance blocks to equalize poor differential signals and more complex algorithms to reduce software overhead and correct bit errors. This article shows how advanced silicon solutions and smartly implemented software can facilitate HDMI implementation.

Two basic devices—HDMI-to-VGA (“HDMI2VGA”) and VGA-to-HDMI (“VGA2HDMI”) converters—provide engineers familiar with video applications with an easy way to transition between analog video and digital video. While HDMI has become a defacto interface for HD video, VGA is still the most common interface on a laptop.

This article also shows how to interconnect these video technologies. Introduction to HDMI Application and Video Standards HDMI interfaces use transition-minimized differential signaling (TMDS) lines to carry video, audio, and data in the form of packets. In addition to these multimedia signals, the interface includes display data channel (DDC) signals for exchanging extended display identification data (EDID) and for high-bandwidth digital content protection (HDCP). Additionally, HDMI interfaces can be equipped with consumer electronics control (CEC), audio return channel (ARC), and home Ethernet channel (HEC). Since these are not essential to the application described here, they are not discussed in this article. EDID data comprises a 128-byte long (VESA—Video Equipment Standards Association) or 256-byte long (CEA-861—Consumer Electronics Association) data block that describes the video and (optionally) audio capabilities of the video receiver (Rx). EDID is read by a video source (player) from the video sink over DDC lines using an I 2C protocol.

A video source must send the preferred or the best video mode supported and listed in EDID by a video sink. EDID may also contain information about the audio capabilities of the video sink and a list of the supported audio modes and their respective frequencies. Both VGA and HDMI have the DDC connection to support the communication between source and sink. The first 128 bytes of EDID can be shared between VGA and HDMI.

From the experience of the HDMI compliance test (CT) lab at Analog Devices, Inc. (ADI), the first 128 bytes of EDID are more prone to error, since some designers are not familiar with the strict requirements of the HDMI specification, and most articles focus on EDID extension blocks. Table 1 shows the portion of the first 128 bytes of EDID that is prone to error. The CEA-861 specification can be referenced for details of the CEA extension block design that may follow the first 128 bytes of the EDID. EDID Basic Introduction Address Bytes Description Comments 00h 8 Header: (00 FF FF FF FF FF FF 00)h Mandatory fixed block header 08h 10 Vendor and product identification 08h 2 ID manufacturer name Three compressed ASCII character code issued by Microsoft ® 12h 2 EDID structure version and revision 12h 1 Version number: 01h Fixed 13h 1 Revision number: 03h Fixed 18h 1 Feature support Features such as power management and color type. Bit 1 should be set to 1. 36h 72 18 byte data blocks 36h 18 Preferred timing mode Indicates one supported timing that can produce best quality on-screen images.

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For most flat panels, the preferred timing mode is the native timing of panel. 48h 18 Detailed timing #2 or display descriptor Indicates detailed timing, or can be used as display descriptor. Two words should be used as the display descriptor, one as the monitor range limit, and one as the monitor name.

Detailed timing block should precede display descriptor block. 5Ah 18 Detailed timing #3 or display descriptor 6Ch 18 Detailed timing #4 or display descriptor 7Eh 1 Extension block count N Number of 128-byte EDID extension blocks to follow. 7Fh 1 Checksum 1-byte sum of all 128 bytes in this EDID block shall equal zero. 80 Block map or CEA extension The timing formats for VGA and HDMI are defined separately by the two standard-setting groups mentioned above: VESA and CEA/EIA. The VESA timing formats can be found in the VESA Monitor Timing and Coordinate Video Timings Standard; the HDMI timing formats are defined in CEA-861. The VESA timing format covers standards, such as VGA, XGA, SXGA, that are used mainly for PCs and laptops. Download Song Mann Mera Table No 21 Pagalworld more. Heli X Crack Simulator Simulator here.

CEA-861 describes the standards, such as 480p, 576p, 720p, and 1080p, that are used in TV and ED/HD displays. Among the timing formats, only one format, 640 × 480p @ 60 Hz, is mandatory and common for both VESA and CEA-861 standards. Both PCs and TVs have to support this particular mode, so it is used in this example. Table 2 shows a comparison between commonly supported video standards. Detailed data can be found in the appropriate specifications.

Witold Kaczurba Witold Kaczurba, a senior applications engineer in the Advanced TV group in Limerick, Ireland, supports decoders and HDMI products. He joined ADI in 2007 after graduating from the Technical University of Wroclaw, Poland, with an MSc in electrical engineering. As a student, he worked for small electronic and IT companies, then joined ADI in Ireland as a co-op student and subsequently as an applications engineer. Related Products • High Performance 8-Bit Display Interface • 165 MHz High Performance HDMI Transmitter • Low Power 165 MHz HDMI Receiver • 330MHz Triple 8-Bit High Speed Video DAC • Low Power Audio Codec • Precision Analog Microcontroller, 12-Bit Analog I/O, ARM7TDMI® MCU Related Markets & Technology • • • •.