
CYP15G0101DXA
PRELIMINARY
Document #: 38-02061 Rev. **
Page 6 of 40
SCSEL
LVTTL Input,
synchronous,
internal pull-down,
sampled by
TXCLK
↑
or REFCLK
↑
[1]
Special Character Select
. Used in some transmit modes along with TXCT[1:0] to en-
code special characters or to initiate a Word Sync Sequence.
Transmit Path Clock and Clock Control
TXCKSEL
3-Level Select
[2]
static control input
Transmit Clock Select
. Selects the clock source, used to write data into the Transmit
Input Register, of the transmit channel.
When LOW, the Input Register is clocked by REFCLK
↑
[1]
.
When HIGH or MID, TXCLK
↑
is the Input Register clock for TXD[7:0] and TXCT[1:0].
Transmit Clock Output
. This true and complement output clock is synthesized by the
transmit PLL and operates synchronous to the internal transmit character clock. It op-
erates at either the same frequency as REFCLK, or at twice the frequency of REFCLK
(as selected by TXRATE). TXCLKO
±
is always equal to the transmit VCO bit-clock
frequency
÷
10. This output clock has no direct phase relationship to REFCLK or the
recovered character clock.
Transmit PLL Clock Rate Select
. When TXRATE = HIGH, the Transmit PLL multiplies
REFCLK by 20 to generate the serial bit-rate clock. When TXRATE = LOW, the transmit
PLL multiples REFCLK by 10 to generate the serial bit-rate clock. See
Table 9
for a list
of operating serial rates.
When REFCLK is selected to clock the receive parallel interface (RXCKSEL = LOW),
the TXRATE input also determines if the clocks on the RXCLK
±
and RXCLKC+ outputs
are full or half-rate. When TXRATE = HIGH, these output clocks are half-rate clocks and
follow the frequency and duty cycle of the REFCLK input. When TXRATE = LOW, these
output clocks are full-rate clocks and follow the frequency and duty cycle of the REFCLK
input.
Transmit Path Input Clock
. This clock must be frequency-coherent to TXCLKO
±
, but
may be offset in phase. The internal operating phase of the input clock (relative to
REFLCK or TXCLKO+) is adjusted when TXRST = LOW and locked when
TXRST = HIGH.
TXCLKO
±
LVTTL Output
TXRATE
LVTTL Input,
Static Control input,
internal pull-down
TXCLK
LVTTL Clock Input,
internal pull-down
Transmit Path Mode Control
TXMODE[1:0]
3-Level Select
[2]
static control inputs
Transmit Operating Mode
. These inputs are interpreted to select one of nine operating
modes of the transmit path. See
Table 3
for a list of operating modes.
Receive Path Data Signals
RXD[7:0]
LVTTL Output,
synchronous to the
RXCLK
↑
output or
REFCLK
↑
[1]
input
LVTTL Output,
synchronous to the
RXCLK
↑
output or
REFCLK
↑
[1]
input
Parallel Data Output
. These outputs change following the rising edge of the selected
receive interface clock.
RXST[2:0]
Parallel Status Output
. These outputs change following the rising edge of the selected
receive interface clock.
When the Decoder is bypassed (DECMODE = LOW), RXST[1:0] become the two low-
order bits of the 10-bit received character, while RXST[2] = HIGH indicates the pres-
ence of a Comma character in the Output Register.
When the Decoder is enabled (DECMODE = HIGH), RXST[1:0] provide status of the
received signal. See
Table 17
for a list of Receive Character status.
Note:
2.
3-Level select inputs are used for static configuration. They are ternary (not binary) inputs that make use of non-standard logic levels of LOW, MID, and HIGH.
The LOW level is usually implemented by direct connection to V
(ground). The HIGH level is usually implemented by direct connection to V
CC
(power). When
not connected or allowed to float, a 3-Level select input will self-bias to the MID level.
Pin Descriptions
(continued)
CYP15G0101DXA Single Channel HOTLink II
Transceiver
Name
I/O Characteristics
Signal Description