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DS90UB949A-Q1
ZHCSJR7 –MAY 2019
www.ti.com.cn
版权 © 2019, Texas Instruments Incorporated
7.3 Feature Description
7.3.1 High-Definition Multimedia Interface (HDMI)
HDMI is a leading interface standard used to transmit digital video and audio from sources (such as a DVD
player) to sinks (such as an LCD display). The interface is capable of transmitting high-definition video and audio.
Other HDMI signals consist of various control and status data that travel bidirectionally.
7.3.1.1 HDMI Receive Controller
The HDMI receiver is an HDMI version 1.4b compliant receiver. The HDMI receiver can operate in up to
2880x1080 at 60 Hz resolution. The configuration used in the DS90UB949A-Q1 does not include version 1.4b
features, such as the ethernet channel (HEC) or Audio Return Channel (ARC).
7.3.2 Transition Minimized Differential Signaling
HDMI uses Transition Minimized Differential Signaling (TMDS) over four differential pairs (three TMDS channels
and one TMDS clock) to transmit video and audio data. TMDS is widely used to transmit high-speed serial data.
The technology incorporates a form of 8b/10b encoding, and the differential signaling allows the device to reduce
electromagnetic interference (EMI) and achieve high skew tolerance.
7.3.3 Enhanced Display Data Channel
The Display Data Channel (DDC) is a collection of digital communication protocols between a computer display
and a graphics adapter that enables the display to send the supported display modes to the adapter. The DDC
also allows the computer host to adjust monitor parameters, such as brightness and contrast.
7.3.4 Extended Display Identification Data (EDID)
EDID is a data structure provided by a digital display to describe the display capabilities to a video source. By
providing this information, the video source can then send video data with the proper timing and resolution that
the display supports. The DS90UB949A-Q1 supports several options for delivering display identification (EDID)
information to the HDMI graphics source. The EDID information is accessible through the DDC interface and
complies with the DDC and EDID requirements given in the HDMI v1.4b specification.
The EDID configurations supported are as follows:
• External local EDID (EEPROM)
• Internal EDID loaded into device memory
• Remote EDID connected to I2C bus at deserializer side
• Internal pre-programmed EDID
The EDID mode selected should be configurable from the MODE_SEL pins or from internal control registers. For
all modes, the EDID information should be accessible at the default address of 0xA0.
7.3.4.1 External Local EDID (EEPROM)
The DS90UB949A-Q1 can be configured to allow a local EEPROM EDID device. The local EDID device may
implement any EDID configuration allowable by the HDMI v1.4b and DVI 1.0 standards, including multiple
extension blocks up to 32KB.
7.3.4.2 Internal EDID (SRAM)
The DS90UB949A-Q1 also allows the internal loading of an EDID profile up to 256 bytes. This SRAM storage is
volatile and requires loading from an external I2C master (local or remote). The internal EDID is reloadable and
readable (local/remote) from control registers during normal operation.
7.3.4.3 External Remote EDID
The serializer copies the remote EDID connected to the I2C bus of the remote deserializer into the internal
SRAM. The remote EDID device can be a standalone I2C EEPROM, or integrated into the digital display panel.
In this mode, the serializer automatically accesses the Bidirectional Control Channel to search for the EDID
information at the default address 0xA0. When the EDID is found, the serializer copies the remote EDID into the
local SRAM.
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