BrightSign HD2000 Hardware Guide - Manual (Page 13)

BrightSign HD2000
This information applies to a product under development. Its characteristics and specifications are subject to change without notice. Roku assumes no
obligation regarding future manufacturing unless otherwise agreed to in writing.
www.rokulabs.com © Roku 2006
Video Encoder and Filter
The PNX8950 streams decoded video out of the QVCP5L port using single data rate clock. The PNX8511
video encoder takes the QVCP5L data in and sends the data straight to the video DACs in HD mode. The
PNX8511 also has an internal SYNC engine that is only used in HD mode to add video sync to the 3
component signals. In VGA mode, the sync signals from the PNX8950 and are passed through the
PNX8511. The PNX8511 mode is controlled by IIC from the PNX8950. Analog video comes out of the
PNX8511 and is connected to the Analog Devices ADA4412 video filter chip. This chip has a
programmable cutoff frequency of either 8MHz, 16MHz or 32MHz. Since the video filter has a low
impedance output, we can drive both VGA and COMPONENT 75Ohm terminated cables at the same
time with no degradation (with the same signal).
HDMI encoder
The QVCP5L video is also sent over to the TDA9982B HDMI encoder chip, which drives the HDMI data
out of the HD2000. The HDMI chip is also connected to I2S audio and SPDIF audio, so that audio will
be driven out the HDMI connector.
Audio outputs
The HD2000 has three high quality audio DAC devices, which are Wolfson WM8729. These devices take
in digital audio signals from the PNX8950 for I2S audio. The AUD_LRCIN signal is the framing signal
for the audio, running at the frame rate of the audio source. The frame rate is usually either 44.1KHz or
48KHz. AUD_BITCLK signal is typically 64 times higher than AUD_LRCIN. The AUD_MCLK is
usually 4 times faster than the AUD_BITCLK signal. The I2S audio is also routed to the HDMI chip.
The audio output from the Wolfson DAC is sent to TPA0211 high quality high power audio amplifiers.
These amplifiers are capable of driving 5 Ohm headphones directly.
SPDIF output
The PNX8950 can generate the SPDIF audio signal internally. This signal, called SPDIF_OPT is
connected to a OPTICAL SPDIF transmitter chip on the board. The SPDIF signal is also routed to the
HDMI chip.
On Board LEDs
There are 18 on board LEDs. One of the LEDs is red in color and is designated to be the BUSY LED. Six
of the LEDs are the resolution LEDs, intended to tell the user what resolution the HD2000 is currently
outputting. The other LEDs are intended to tell the user which output connectors are active. All the LEDs
are controlled by a set of 3 74HC574 latches. Data is latched into the latches under GPIO control. The far
left green LED is the power LED. The far right RED LED is the flash activity LED, which flashes
anytime the SD or CF is being accessed.