CY7B923
CY7B933
Document #: 38-02017 Rev. *E
Page 4 of 33
VCCN
Power for output drivers.
VCCQ
Power for internal circuitry.
GND
Ground.
CY7B933 HOTLink Receiver
Name
I/O
Description
Q0−7
(Qb − h)
TTL Out
Q0–7 Parallel Data Output. Q0–7 contain the most recently received data. These outputs change
synchronously with CKR. When MODE is HIGH, Q0, 1, ...7 become Qb, c,...h, respectively.
SC/D (Qa)
TTL Out
Special Character/Data Select. SC/D indicates the context of received data. HIGH indicates a
Control (Special Character) code, LOW indicates a Data character. When MODE is HIGH (placing the
receiver in Unencoded mode), SC/D acts as the Qa output. SC/D has the same timing as Q0−7.
RVS (Qj)
TTL Out
Received Violation Symbol. A HIGH on RVS indicates that a code rule violation has been detected
in the received data stream. A LOW shows that no error has been detected. In BIST mode, a LOW
on RVS indicates correct operation of the Transmitter, Receiver, and link on a byte-by-byte basis.
When MODE is HIGH (placing the receiver in Unencoded mode), RVS acts as the Qj output. RVS has
the same timing as Q0−7.
RDY
TTL Out
Data Output Ready. A LOW pulse on RDY indicates that new data has been received and is ready
to be delivered. A missing pulse on RDY shows that the received data is the Null character (normally
inserted by the transmitter as a pad between data inputs). In BIST mode RDY will remain LOW for all
but the last byte of a test loop and will pulse HIGH one byte time per BIST loop.
CKR
TTL Out
Clock Read. This byte rate clock output is phase and frequency aligned to the incoming serial data
stream. RDY, Q0−7, SC/D, and RVS all switch synchronously with the rising edge of this output.
A/B
PECL in
Serial Data Input Select. This PECL 100K (+5V referenced) input selects INA or INB as the active
data input. If A/B is HIGH, INA is connected to the shifter and signals connected to INA will be decoded.
If A/B is LOW INB is selected.
INA
±
Diff In
Serial Data Input A. The differential signal at the receiver end of the communication link may be
connected to the differential input pairs INA
± or INB±. Either the INA pair or the INB pair can be used
as the main data input and the other can be used as a loopback channel or as an alternative data
input selected by the state of A/B. One input of an intentionally unused differential-pair (INA
± or INB±)
should be terminated to VCC through a 1−5 KΩ resistor to assure that no data transitions are acciden-
tally created.
INB
(INB+)
PECL in
(Diff In)
Serial Data Input B. This pin is either a single-ended PECL data receiver (INB) or half of the INB
differential pair. If SO is wired to VCC, then INB± can be used as differential line receiver inter-
changeably with INA
±. If SO is normally connected and loaded, INB becomes a single-ended PECL
100K (+5V referenced) serial data input. INB is used as the test clock while in Test mode.
SI
(INB
−)
PECL in
(Diff In)
Status Input. This pin is either a single-ended PECL status monitor input (SI) or half of the INB
differential pair. If SO is wired to VCC, then INB± can be used as differential line receiver inter-
changeably with INA
±. If SO is normally connected and loaded, SI becomes a single-ended PECL
100K (+5V referenced) status monitor input, which is translated into a TTL-level signal at the SO pin.
SO
TTL Out
Status Out. SO is the TTL-translated output of SI. It is typically used to translate the Carrier Detect
output from a fiber-optic receiver connected to SI. When this pin is normally connected and loaded
(without any external pull-up resistor), SO will assume the same logical level as SI and INB will become
a single-ended PECL serial data input. If the status monitor translation is not desired, then SO may
be wired to VCC and the INB± pair may be used as a differential serial data input.
RF
TTL In
Reframe Enable. RF controls the Framer logic in the Receiver. When RF is held HIGH, each SYNC
(K28.5) symbol detected in the shifter will frame the data that follows. If it is HIGH for 2,048 consecutive
bytes, the internal framer switches to double-byte mode. When RF is held LOW, the reframing logic
is disabled. The incoming data stream is then continuously deserialized and decoded using byte
boundaries set by the internal byte counter. Bit errors in the data stream will not cause alias SYNC
characters to reframe the data erroneously.
CY7B923 HOTLink Transmitter (continued)
Name
I/O
Description
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