tda9981ahl/8/c1xx NXP Semiconductors, tda9981ahl/8/c1xx Datasheet - Page 21

• Manufacturer Part Number: tda9981ahl/8/c1xx
• Description: Hdmi Transmitter Up To 150 Mhz Pixel Rate With 3 ? 8-bit Video Inputs And 4 ? I 2s-bus With S/pdif
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TDA9981A_1
Product data sheet
8.14.1 Repeater function
8.14.2 SHA-1
8.15.1 Output HDMI buffers
8.15.2 Pixel repetition
8.14 High-bandwidth digital content protection
8.15 HDMI
The HDMI transmitter contains an HDCP function which encrypts the transmitted stream
content (video and audio); this function can be disabled via the I
stored internally in OTP non-volatile memory or can be loaded via the I
are stored internally, the security is maximized.
The TDA9981A can be used in a repeater device according to HDCP 1.1 specification and
HDMI 1.2a specification.
The TDA9981A can handle up to 9 devices connected downstream.
To deal with the repeater, a SHA-1 calculation is performed by the transmitter and by the
downstream repeater. For security purposes and in order to relieve the microcontroller,
the SHA-1 has been implemented within the TDA9981A. This calculation is worked out
after the transmitter has loaded the KSV list (see HDCP 1.1 specification ). If the SHA-1
calculated by the transmitter equals the SHA-1 calculated by the repeater, then an
interrupt (register INT_FLAGS_0, bit SHA-1) is sent.
An external resistor must be used to set the HDMI output amplitude. It has to be
connected between pin EXT_SWING and V
To transmit video formats with pixel rates below 25 Msample/s or to increase the number
of audio sample packets in each frame, the TDA9981A uses pixel repetition to increase
the transmitted pixel clock.
Table 16.
PIX_REP[3]
0
0
0
0
0
0
0
0
1
1
1
1
Pixel repetition
PIX_REP[2]
0
0
0
0
1
1
1
1
0
0
0
1
Rev. 01 — 19 May 2008
PIX_REP[1]
0
0
1
1
0
0
1
1
0
0
1
x
DDH(3V3)
150 MHz pixel rate HDMI transmitter
.
PIX_REP[0]
0
1
0
1
0
1
0
1
0
1
x
x
2
C-bus. The keys can be
TDA9981A
2
© NXP B.V. 2008. All rights reserved.
C-bus. If the keys
Pixel repeated
no repetition
once
twice
3 times
4 times
5 times
6 times
7 times
8 times
9 times
undefined
undefined
21 of 40