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SAA7115_Datasheet.fm
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Philips Semiconductors
CS-PD Hamburg
CVIP2
Datasheet
SAA7115
Date:
10/23/01
Version:
0.67
9
INPUT/OUTPUT INTERFACES AND PORTS
The SAA7115 has 5 different I/O interfaces:
Analog video input interface, for analog CVBS and/or Y and C input signals
Audio clock port
Digital real-time signal port (RT port)
Digital image port (I-port) for scaled video data output and programming
Digital host port (H-port) for extension of the image port (output mode) or expansion port (input mode) from 8 to 16-bit.
9.1
Analog terminals
The SAA7115 has 6 analog inputs AI21 to AI24 and AI11 to AI12 for composite video CVBS or S-video Y/C signal pairs.
Additionally, there are two differential reference inputs, which must be connected to ground via a capacitor equivalent to
the decoupling capacitors at the 6 inputs. Per connected input there are no peripheral components required other than
a decoupling capacitor of 47nF directly connected to the analog device inputs pins), an 18
(connected in series directly
to the source) and 56
(connected between the capacitor and the 18
resistor to ground) termination resistor. Two
anti-alias filters are integrated.
Clamp and gain control for the ADCs are also integrated. An analog video output (pin AOUT) is provided for testing
purposes.
Table 32
Analog pin description
9.2
Audio clock signals
The SAA7115 also synchronizes the audio clock and sampling rate to the video frame rate, via a very slow PLL. This
ensures that the multimedia capture and compression processes always gather the same predefined number of samples
per video frame.
There are two basic modes as described in chapter 8.7 . Depending on these modes the signals AMCLK, ASCLK and
ALRCLK are generated (Note: To generate ASCLK and ALRCLK the Audio Master clock AMCLK must be fed back into
the device via the AMXCLK pin.).
Generating a frame locked Audio Master clock without using the second analog PLL (CGC2):
– AMCLK: is the audio clock.
– ASCLK: can be used as audio serial clock.
– ALRCLK: audio left/right channel clock.
Generating a low jitter frame locked Audio Master clock supported by the second analog PLL (CGC2):
SYMBOL
PIN
I/O
DESCRIPTION
BIT
AI11 and AI12
AI21, AI22,
AI23 and AI24
20, 18
16, 14, 12,
10
I
analog video signal inputs, e.g. six CVBS signals or two
Y/C plus two CVBS pairs signal groups can be connected
simultaneously to this device; several combinations are
possible; see table 54.
analog video output, for test purposes
MODE3 to MODE0
(02H[3:0])
AOUT
22
O
AOSL2 to AOSL0
(01H[7], 14H[5:4])
AI1D, AI2D
19, 13
I
analog reference pins for differential ADC operation;
connect to ground via 47 nF