cbtl12131 NXP Semiconductors, cbtl12131 Datasheet - Page 12

• Manufacturer Part Number: cbtl12131
• Description: Cbtl12131 Displayport Multiplexer For Bidirectional Video In All-in-one Computer Systems
• Manufacturer: NXP Semiconductors

NXP Semiconductors
Table 5.
Legend: high-Z = isolating, high-impedance; ACT = active, low-impedance.
CBTL12131
Product data sheet
PATH_SEL HPD_B_FLT DDC_AUX_SEL Port C - Port D
0
0
0
1
1
AUX/DDC channel configuration
7.4 HPD signal path
Inputs
0
1
1
0
1
The HPD signal path, unlike the Main Link and AUX/DDC paths, uses active LVTTL logic
rather than passive switching. As shown in
Main Link and AUX channels but with the signal direction in reverse direction (since the
HPD signal direction is always from sink to source). When PATH_SEL is LOW, output
HPD_C follows and re-drives input HPD_D and similarly HPD_A follows the logic state of
input HPD_B. An integrated 200 kΩ resistor (RPD_HPD) between HPD_B and GND
ensures a logic LOW when no device is connected to Port B. When PATH_SEL is HIGH,
HPD_B becomes an output and follows the logic state of HPD_D. Please also refer to
Section 7.6
Fig 7.
HPD channel topology
X
0
1
X
X
for specific details on the HPD filtering function.
HPD_C
HPD_A
All information provided in this document is subject to legal disclaimers.
PATH_SEL = 0: active
PATH_SEL = 1: LOW
Rev. 1 — 25 February 2011
high-Z
high-Z
ACT
ACT
ACT
AUX_A
high-Z
high-Z
high-Z
high-Z
Port A - Port B
ACT
DisplayPort multiplexer for bidirectional video
Channel
PATH_SEL = 0: high-Z
PATH_SEL = 1: active
Figure
DDC_A
high-Z
high-Z
high-Z
high-Z
ACT
7, the topology follows that of the
R PD_HPD
R PD_HPD
Port B - Port D
high-Z
high-Z
high-Z
ACT
ACT
CBTL12131
002aaf999
HPD_D
HPD_B
Comment
(all other ports
shall be mutually
isolated)
Normal mode;
internal display only
Normal mode with
dual display
Normal mode with
dual display using
++DP display
adaptor
External source
mode with internal
display not yet
asserting HPD
External source
mode with internal
display asserting
HPD
© NXP B.V. 2011. All rights reserved.
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