DS21FT44/DS21FF44
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Signal Name:
RMSYNC
Signal Description:
Receive Multiframe Sync
Signal Type:
Output
An extracted pulse, one RSYSCLK wide, is output at this pin which identifies multiframe boundaries. If
the receive side elastic store is disabled, then this output will output multiframe boundaries associated
with RCLK. This function is available when FMS = 1 (DS21Q43 emulation). This signal is not bonded
out in the DS21FF44/DS21FT44.
Signal Name:
RSYSCLK
Signal Description:
Receive System Clock
Signal Type:
Input
1.544 MHz or 2.048 MHz clock. Only used when the elastic store function is enabled. Should be tied
low in applications that do not use the elastic store. Can be burst at rates up to 8.192 MHz. This pin is
tied to the TSYSCLK signal in the DS21FF44/DS21FT44.
Signal Name:
RSIG
Signal Description:
Receive Signaling Output
Signal Type:
Output
Outputs signaling bits in a PCM format. Updated on rising edges of RCLK when the receive side elastic
store is disabled. Updated on the rising edges of RSYSCLK when the receive side elastic store is
enabled. This function is available when FMS = 0. FMS is tied to ground for the DS21FF44/DS21FT44.
Signal Name:
RLOS/LOTC
Signal Description:
Receive Loss of Sync / Loss of Transmit Clock
Signal Type:
Output
A dual function output that is controlled by the TCR2.0 control bit. This pin can be programmed to either
toggle high when the synchronizer is searching for the frame and multiframe or to toggle high if the
TCLK pin has not been toggled for 5 usec.
This function is available when FMS = 1 (DS21Q43
emulation). This signal is not bonded out in the DS21FF44/DS21FT44.
Signal Name:
CLKSI
Signal Description:
8 MHz Clock Reference
Signal Type:
Input
A 2.048 MHz reference clock used in the generation of 8MCLK. This function is available when FMS =
0. FMS is tied to ground for the DS21FF44/DS21FT44.
Signal Name:
8MCLK
Signal Description:
8 MHz Clock
Signal Type:
Output
A 8.192 MHz output clock that is referenced to the clock that is input at the CLKSI pin. This function is
available when FMS = 0. FMS is tied to ground for the DS21FF44/DS21FT44.
Signal Name:
RPOS
Signal Description:
Receive Positive Data Input
Signal Type:
Input
Sampled on the falling edge of RCLK for data to be clocked through the receive side framer. RPOS and
RNEG can be tied together for an NRZ interface. Connecting RPOS to RNEG disables the bipolar
violation monitoring circuitry.