March 01, 1999, Issue: 1050
Section: News
Digital-interface spec for monitors trashes analog
David Lieberman
Palm Springs, Calif. - The PC world declared war on analog last week at the
Intel Developer Forum here, as the Digital Display Working Group (DDWG)
presented a soup-to-nuts digital-interface specification for monitors, along
with early flat-panel implementations and even a compliant digital-input CRT.
Vendors demonstrated six flat-panel monitors with the interface on-board at
the working group's technology showcase. And at an Intel "fashion show" of
small form-factor computers, all of the exhibited machines' motherboards had
built-in DVI.
"We got the analog off those motherboards," said Steve Spina,
strategic-initiative manager for graphics at Intel's desktop products group.
"The common goal of the DDWG is the eventual removal of analog altogether.
Analog is the next thing on the legacy-removal road map."
Hammered out in about five months, DVI has two noteworthy cornerstones:
no options and no royalties. "We really didn't want any options [like USB and
IEEE 1394] in this," said Scott Macomber, president of Silicon Image Inc.
(Cupertino, Calif.), which supplies the transmission-minimized
differential-signaling (TMDS) transceivers on which DVI is based. "That's part
of what caused the confusion and the split" between two earlier
digital-interface efforts: the 20-pin connector proposed by the Digital Flat
Panel (DFP) initiative and the Video Electronic Standards Association's Plug
& Display (P&D) interface, which uses a 30-pin connector. A format war
between those initiatives broke out last summer (see June 8, 1998, page 1).
The Digital Display Working Group formed in the fall to hammer out a
"convergence spec" acceptable to the PC, graphics and monitor industries
(see Sept 21, 1998, page 4).
Spina said DVI had to be made sufficiently "robust and complete to ensure
complete interoperability and [to ensure that], if there are any patents in there,
you won't get sued."
The working group-comprising Intel, Compaq, IBM, Hewlett-Packard,
Fujitsu, Microsoft, NEC, Dell and Silicon Image-delivered a Version 0.9 spec
to the forum. The complete technical specification offers a blueprint for
building compatible products, covering architecture, protocols and the
electrical and mechanical interfaces.
"To make sure we can have compatible products built, we need to put [the
spec] out for industry review to tell us where it may need clarification," Spina
said. Hence the 0.9 designation.
The working group has settled on one connector to support several DVI
flavors: digital-only and digital plus high-performance analog, for example,
with the digital section the same for both versions. It also handles single- and
dual-channel operation, the former for formats up to 1,600- x 1,200-pixel
UXGA, the latter for higher pixel counts.
"It needs to be easy for consumers," Macomber said, defining "easy" thus: "If
the connector plugs in, it works, and whatever features are there are going to
work."
The DDWG group acknowledges that analog will remain a transitional
requirement. "We realized as a group that there are probably two markets,"
said Spina: "systems that can't get that 15-pin analog connector off the back of
the box in a hurry, so they'll want digital only, and bundled systems-say, in
niche workstation markets-where they can transition [to DVI] very quickly,
going to a single integrated connector and then eventually getting rid of the
analog."
Allen Alley, president and chief executive officer of Pixelworks Inc. (Tualatin,
Ore.), a display-controller chip com-pany, believes "the smoothest possible
transition will be to introduce digital displays alongside analog displays. This
allows customers to dictate the pace of adoption.
"As an industry, we must work together to avoid forcing end users to choose
between analog and digital, which could inhibit adoption of flat-panel display
technology altogether. We foresee demand for both analog- and
digital-interface monitors continuing to expand for a minimum of three years."
The Digital Display Working Group pavilion included monitors with flat-panel
displays: a 25-inch plasma monitor from Fujitsu; a 42-inch plasma and
15-inch LCD monitor from Philips; 18-inch LCD monitors from IBM and
Compaq; and a Silicon Graphics 17.3-inch wide-screen monitor, driven by a
graphics board from Number Nine Visual Technology Corp.
The dual-channel configuration of DVI was defined "to support future
bandwidth requirements," Macomber said, "but we weren't thinking about
LCD monitors or plasma monitors in particular." In fact, the DDWG group
was thinking bout CRTs-which, unlike most flat panels, are basically analog
displays.
"The real opportunity is more than just doing the D/A conversion in the
monitor," Macomber said. "Now that there's a viable digital interface
standard, you can think about redoing all of the electronics, simplifying the
monitor manufacture and design and lowering the overall costs."
Spina said the working group strove for display independence. "There were
77 million analog [input] CRTs shipped last year," he said. "In the next six
months, we'll look at how to enable that industry to move [to digital input] as
well." |
