Texas Instruments TMS380C26 - Manual (Page 16)

TMS380C26
NETWORK COMMPROCESSOR
SPWS010A–APRIL 1992–REVISED MARCH 1993
POST OFFICE BOX 1443
•
HOUSTON, TEXAS
77251–1443
16
Terminal Functions (continued)
Network Media Interface – Token-Ring Mode (TEST1 = H, TEST2 = H)
PIN NAME NO. I/O DESCRIPTION
DRVR
DRVR 89
88
OUT
Differential Driver Data Output. These pins are the differential outputs that send the TMS380C16
transmit data to the TMS38054 for driving onto the ring transmit signal pair.
FRAQ/TXD 85 OUT
Frequency Acquisition Control. This TTL output determines the use of frequency or phase acquisition
mode in the TMS38054.
H = Wide range. Frequency centering to PXTALIN by TMS38054.
L
= Narrow range. Phase-lock onto the incoming data (RCVINA and RCVINB) by the
TMS38054.
NSRT/LPBK 86 OUT
Insert Control Signal to the TMS38054. This TTL output signal enables the phantom driver outputs
(PHOUTA and PHOUTB) of the TMS38054, through the watchdog timer, for insertion onto the
Token-Ring.
Static High = Inactive, phantom current removed (due to watchdog timer)
Static Low = Inactive, phantom current removed (due to watchdog timer)
NSRT Low and Pulsed High = Active, current output on PHOUTA and PHOUTB
PXTALIN/TXC 92 IN
Ring Interface Clock Frequency Control (see Note 5). At 16-Mbps ring speed, this input must be
supplied a 32-MHz signal. At 4-Mbps ring speed, the input signal must be 8-MHz and may be the
output from the OSCOUT pin.
RCLK/RXC 94 IN
Ring Interface Recovered Clock (see Note 5). This input signal is the clock recovered by the
TMS38054 from the Token-Ring received data.
For 16-Mbps operation it is a 32-MHz clock.
For 4-Mbps operation it is an 8-MHz clock.
RCVR/RXD 95 IN
Ring Interface Received Data (see Note 5). This input signal contains the data received by the
TMS38054 from the token ring.
REDY/CRS 84 IN
Ring Interface Ready. This input pin provides an indication of the presence of received data, as
monitored by the TMS38054 energy detect capacitor.
H = Not ready. Ignore received data.
L
= Ready. Received data.
WFLT/COLL 87 IN
Wire Fault Detect. This signal is an input to the TMS380C16 driven by the TMS38054. It indicates
a current imbalance of the TMS38054 PHOUTA and PHOUTB pins.
H = No wire fault detected.
L
= Wire fault detected.
WRAP/TXEN 90 OUT
Internal Wrap Select. This signal is an output from the TMS380C16 to the ring interface to activate
an internal attenuated feedback path from the transmitted data (DRVR) to receive data (RCVR)
signals for bring-up diagnostic testing. When active, the TMS38054 also cuts off the current drive to
the transmission pair.
H = Normal ring operation.
L
= Transmit data drives receive data (loopback).
NOTE 5: Pin has an expanded input voltage specification.