Philips DV29 service manual HDMI output stage, VSYNC - Vertical sync data HSYNC - Horizontal sync

HDMI output stage

Please note: Due to the plug and play nature of the HDMI/DVI interface, if presented with a reported no HDMI problem it is worth checking all set-up parameters of both the DVD player and the Plasma/Projector in use before performing component level diagnostics on this section.

HDMI is a system that transmits uncompressed digital video and digital audio over a high speed encrypted interface.

IC1102 is an SII9030 HDMI transmitter IC in essence the chip takes the Digital Video and Audio information and sends the Data out in HDMI format.

REG1100 is used to generate a clean regulated 3V3 power supply to Pins 18 and 33 of the HDMI chip.

IC1100 –IC1101 are 3 state octal/line drivers these form a multiplex that switches between the 2 groups of signals for the video data input stage of the SII9190 the multiplexer is control by the Signal from the Vaddis V labelled as PROG/INT this will sit at logic 1 for Progressive scan and logic 0 for interlaced.

In interlaced mode the 8 bit Y/Cb/Cr video data on VIDP7-0are passed to input port pins D15 – D8 of the SII9190.

In Progressive scan mode all 20 bits of the Video data bus are used and get mapped as follow.

VIDP 19 -12 provide 8 msbits of Y data to pins D15-8 VIDP 11 -10 provide 2Isbits of Y data to pins D2-3

VIDP 9 - 2 provide 8 msbits of Cb/Cr data to pins D23 – 16 VIDP 1 – 0 provide 2 Isbits of Cb/Cr data to pins D7 - 6

Along with the VIDP video data lines we must also see

VSYNC – Vertical sync data

HSYNC – Horizontal sync

CLK27M_VID – 27Mhz video clock.

SPDIF – Digital audio data (Full surround) MCLK_HDMI – Used to strobe HDMI dig audio

At the output of the HDMI chip we will see the following signals at SKT100.

TMDS (Transistion Minimised Differential Signalling) this consists of a clock signal (TXC+/TXC-) and 3 data signals (TX0+/TX0-, TX1+/TX1- and TX2+/TX2-).

All signals are differential and use current switching techniques therefore no signals will be observed unless the output is correctly terminated. In this application the clock signal will always be 27MHz and the data signals will be clock X10 so 270Mbit/s.

DDC Channel this is a 12C interface on DDC_SCL and DDC_SDA. These signals connect to the VADDIS V which is the I2C bus master, The DDC channel is used to read back information from the HDMI sync regarding it’s Video and Audio capabilities and is also used for HDCP encryption authentication.

+5V Power, the HDMI interface requires a 5V supply capable of delivering around 50mA, the supply is provided by REG 1101 which delivers the required current and will shut down in the event of a short circuit.

Hotplug. The HDMI `Hot plug’ signal HDPIN is a +5V to signal the presence of equipment being connected, this converted to 3v3 logic 1 as IC1100 is not +5V tolerant.

CEC. The CEC (Consumer Electronics Control) signal is a 1-wire bidirectional control signal. It connects to the Vaddis via an ESD protection circuit D1102 at the moment this line is not used at present and is an optional part of the HDMI specification.