Analog Devices ADV8003, Руководство по оборудованию

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ADV8003 Hardware Manual
Rev. B, August 2013 246
Register Map Register Map Address
HDMI Tx2 EDID Map 0xF600 – 0xF6FF
HDMI Tx2 CEC Map 0xF800 – 0xF8FF
HDMI Tx2 UDP Map 0xFA00 – 0xFAFF
HDMI Tx2 Test Map 0xFB00 – 0xFBFF
It should be noted that the section on the HDMI transmitter, while referring to HDMI Tx1, also equally applies to HDMI Tx2. The same
register bits and controls as per
Table 45 apply for both transmitters.
6.1. GENERAL CONTROLS
To operate the HDMI Tx core, it is necessary to monitor the Hot Plug Detect (HPD) signal from the downstream sink and power up the
Tx core after the appropriate HPD becomes high. To power up the Tx core,
system_pd must be programmed to 0 when the HPD_TX1 pin
is high. The status of the HPD_TX1 pin is provided via hpd_state .
Some registers cannot be written to when the signal on the HPD_TXx input pin is low. When the level on the HPD_TX1 pin goes from
high to low, some registers will be reset to their default value.
The best method to determine when the level of the signal on the HPD_TXx pin is high is to use the interrupt system. An interrupt can be
enabled to notify level change on the HPD_TXx pin (refer to Section
8 for more details regarding the ADV8003 interrupts).
The ADV8003 also features a
rx_sense_state status bit which can be used to detect the presence of TMDS clock terminations from the
sink. If the ADV8003 detects a voltage level higher than 1.8 V on the clock lines of its TMDS output port, rx_sense_int is triggered and
rx_sense_state is set to 1.
The detection of TMDS clock terminations from downstream sink devices is useful to delay powering up the transmitter sections until the
downstream sink devices are actually ready to receive signals. A typical implementation for a sink is to tie the transmitter 5 V power signal
to HPD through a series resistor. In this case, the ADV8003 will detect a high level on HPD_TX1 (HPD_TX2 for HDMI Tx 2) regardless
of whether or not the downstream sink is powered on and ready to receive a TMDS stream. For this reason, it is best to wait for both the
rx_sense_state and hpd_state to be high before powering up the Tx core when trying to achieve minimum power consumption.
system_pd
, TX2 Main Map, Address 0xF441[6]
This bit is used to power down the Tx.
Function
system_pd Description
0 Normal operation
1  Power down Tx
hpd_state , TX2 Main Map, Address 0xF442[6] (Read Only)
This bit is used to read back the state of the hot plug detect.
Function
hpd_state Description
0  Hot Plug Detect inactive (low)
1 Hot Plug active (high)
hpd_override[1:0]
, TX2 Main Map,
Address 0xF49F[5:4]
This signal is used to select the source of the internal HPD signal.