
Brooktree
9
F
UNCTIONAL
D
ESCRIPTION
Pin Descriptions
L848A_A
Bt848/848A/849A
Single-Chip Video Capture for PCI
General Purpose I/O (27 pins)
82–89,
92–99,
110–117
GPIO[23:0]
I/O
General Purpose
I/O
24 bits of programmable I/O. These pins are internally pulled
up to VDDG.
GPIO[23]
GPIO[22]
GPIO[21]
GPIO[20]
GPIO[19]
GPIO[18]
GPIO[17]
GPIO[16]
GPIO[9]
GPIO[8]
GPIO[7:0]
O
O
O
O
O
O
O
O
I
I
I
Clkx1
Field
Vactive
Vsync
Hactive
Hsync
Composite Active
Composite Sync
Vsync/Field
Hsync
Video Data Input at
GPCLK = CLKX2
rate
Bt848A and Bt849A pin decoding when in digital video input
and SPI mode.
119
GPINTR
I
GP Interrupt
GP port requests an interrupt. Internally pulled up to VDDG.
118
GPWE
I
GP Write Enable
GP port write enable for registered inputs. Internally pulled up
to VDDG.
108
GPCLK
I/O
GP Clock
Video clock. Internally pulled up to VDDG.
Input Stage (14 pins)
141
MUX0
I
Analog composite video inputs to the on-chip input multi-
plexer. Used to select between three composite sources or
two composite and one S-video source. Unused pins should
be connected to ground.
143
MUX1
I
145
MUX2
I
139
MUXOUT
O
The analog video output of the 3 to 1 multiplexer. Must con-
nect to the YIN pin.
138
YIN
I
The analog composite or luma input to theY-ADC.
154
CIN
I
The analog chroma input to the C-ADC.
147
SYNCDET
I
The sync stripper input used to generate timing information
for the AGC circuit. Must be connected through a 0.1
μ
F
capacitor to the same source as the Y-ADC. A 1 M
bleeder
resistor should be connected to ground.
MUX3
I
In the Bt848A and Bt849A the SYNCDET is not required and
is used as a fourth mux input.
Analog composite video inputs to the on-chip input multi-
plexer. Used to select between three composite sources or
two composite and one S-video source. Unused pins should
be connected to ground.
131
AGCCAP
A
The AGC time constant control capacitor node. Must be con-
nected to a 0.1
μ
F capacitor to ground.
Table 2. Pin Descriptions Grouped by Pin Function
(3 of 6)
Pin #
Pin Name
I/O
Signal
Description