FIN24AC Fairchild Semiconductor, FIN24AC Datasheet - Page 12

• Manufacturer Part Number: FIN24AC
• Description: Fin24ac ? ?serdes? 22-bit Bi-directional Serializer/deserializer
• Manufacturer: Fairchild Semiconductor

© 2005 Fairchild Semiconductor Corporation
FIN24AC Rev. 1.0.3
Figure 13 shows a half-duplex connectivity diagram. This
connectivity allows for two unidirectional data streams to
be sent across a single pair of SerDes devices. Data is
sent on a frame-by-frame basis. For this mode, there
must be some synchronization between when the cam-
era sends its data frame and when the LCD sends its
data. One option is to have the LCD send data during the
camera blanking period. External logic may be needed
for this mode of operation.
Devices alternate frames of data controlled by a direction
control and a direction sense. When DIRI on the right-
hand FIN24AC is HIGH, data is sent from the camera to
the camera interface at the base. When DIRI on the
Flex Circuit Design Guidelines
The serial I/O information is transmitted at a high serial rate. Care must be taken implementing this serial I/O flex
cable. The following best practices should be used when developing the flex cabling or Flex PCB:
■
■
■
■
■
Keep all four differential wires the same length.
Allow no noisy signals over or near differential serial wires. Example: No LVCMOS traces over differential wires.
Use only one ground plane or wire over the differential serial wires. Do not run ground over top and bottom.
Do not place test points on differential serial wires.
Use differential serial wires a minimum of 2cm away from the antenna.
Base
Camera
Unit
LCD
Unit
Unit
GPIO
VSYNC/HSYNC
Figure 13. Multiple Units, Unidirectional Signals in Each Direction
PwrDwn
Camera/LCD Select
CKREF
STROBE
DP[21:22]
DP[1:20]
DP[23:24]
DIRO
S1
S2
FIN24AC
CKSO
CKSI
DIRI
DS
12
right-hand FIN24AC goes LOW, is sent from the base-
band process to the LCD. The direction is then changed
at DIRO on the right-hand FIN24AC, indicating to the
left-hand FIN24AC to change direction. Data is sent
from the base LCD unit to the LCD. The DIRO pin on the
left-hand FIN24AC is used to indicate to the base control
unit that the signals are changing direction and the LCD
is available to receive data. DIRI on the right-hand
FIN24AC could typically use a timing reference signal,
such as VSYNC from the camera interface, to indicate
direction change. A derivative of this signal may be
required to make sure that no data is lost in the final data
transfer.
CKSI
DS
CKSO
DIRO
FIN24AC
DP[23:24]
DP[21:22]
STROBE
DP[1:20]
CKREF
CKP
DIRI
S1
S2
VSYNC/HSYNC
Disable
Camera
www.fairchildsemi.com
LCD