signal is retimed to signify to the
host that the Tx is ready to send
data (RFD). Other configurations
for duplex mode are also possible
with external user-defined state
machines. Simplex operation
using G-LINK is also possible. The
following sections discuss three
different types of simplex
Simplex Method I. Simplex
with Low-Speed Return Path
Low-speed lines are used in the
simplex method of Figure 17a.
The remote Rx controls the states
of both the Rx and the local Tx
using these low speed lines. This
is ideal for cases where these non-
critical lines are available. Again,
a power on reset is available to
the user. This connection between
the Tx and Rx is identical to one
side of the duplex configuration.
When the Tx is locked, the Rx is
enabled via the LOCKED line. The
Rx’s STAT0 and STAT1 outputs
are low, causing the local Tx to
send FF0. When the Rx is frame
locked, STAT1 is raised, which
disables its frequency detector,
sets itself to active mode, and tells
Tx to send FF1. Upon receiving
FF1 from the Tx, the Rx’s STAT0
line is raised, which enables the
Tx (ED) for data transmission. If
desired, the Rx reset pin
configurations.
(SMCRST1) can be tied high, and
the LOCKED line can be
eliminated.
Tx
Rx
DOUT
DIN
LIN
Rx DATA
INTERFACE
Tx DATA
INTERFACE
LOUT
OPTIONS
OPTIONS
POWER-ON
RESET
POWER-ON
RESET
LOW SPEED LINES
A) SIMPLEX METHOD 1 WITH LOW-SPEED RETURN PATH
Tx
Rx
DOUT
LOUT
DIN
LIN
Rx DATA
INTERFACE
Tx DATA
INTERFACE
OPTIONS
OPTIONS
POWER-ON RESET
POWER-ON
RESET
PERIODIC
SYNC PULSES
V
CC
B) SIMPLEX METHOD 2 WITH PERIODIC SYNC PULSE
Tx
Rx
DOUT
LOUT
LIN
DIN
Tx DATA
INTERFACE
Rx DATA
INTERFACE
OPTIONS
OPTIONS
OSC
POWER-ON
RESET
POWER-ON
RESET
FREQ = FRAME RATE
V
CC
C) SIMPLEX METHOD 3 WITH EXTERNAL REFERENCE OSCILLATOR
Figure 17. Simplex Configurations.
648
AGILENT [ AGILENT TECHNOLOGIES, LTD. ]
