Rainbow Electronics DS3170 - Manual (Page 76)

DS3170 DS3/E3 Single-Chip Transceiver
76 of 233
long. The generated BERT signal replaces the data on the TSER pin in framed modes when the BERT is enabled
by setting the PORT.CR1.BENA.
When the BERT is enabled The TDEN and RDEN pins will still be active but the data on the TSER pin will be
discarded.
9.5.8 System Port Pins
The system port pins have multiple functions based on the framing mode the device is in as well as other pin mode
select bits.
9.5.8.1 Transmit System Port Pins
The transmit system pins are TSOFI, TSER, TSOFO / TDEN, and TCLKO / TGCLK. They have different functions
based on the framing mode and other pin mode bits. Unused input pin functions should drive a logic zero into the
device circuits expecting a signal from that pin. The control bits that configure the pins’ modes are
PORT.CR2. FM[2:0], PORT.CR3. TPFPE, PORT.CR3. TSOFOS and PORT.CR3. TCLKS.
Table 9-20 to Table 9-22 describe the function selected by the FM bits and other pin mode bits for the multiplexed
pins.
Table 9-20. TSOFI Input Pin Functions
FM[2:0]
PORT.CR2
PIN
FUNCTION
0XX (FRM) TSOFI
1XX (UFRM) Not used
Table 9-21. TSOFO/TDEN/Output Pin Functions
FM[2:0]
PORT.CR2
TSOFOS
PORT.CR3
PIN
FUNCTION
0XX (FRM) 0 TDEN
0XX (FRM) 1 TSOFO
1XX (UFRM) X High
Table 9-22 TCLKO/TGCLK Output Pin Functions
FM[2:0]
PORT.CR2
TCLKS
PORT.CR3
PIN
FUNCTION
GAP SOURCE
0XX (FRM) 0 TGCLK TDEN
0XX (FRM) 1 TCLKO none
1XX (UFRM) X TCLKO none
9.5.8.2 Receive System Port Pins
The receive system pins are RSER, RSOFO / RDEN and RCLKO / RGCLK. They have different functions based
on the framing mode and other pin mode bits. Unused input pin functions should drive a logic zero into the device
circuits expecting a signal from that pin. The control bits that configure these pins are
PORT.CR2. FM[2:0],
PORT.CR3. RPFPE, PORT.CR3. RSOFOS and PORT.CR3. RCLKS.
Table 9-23 to Table 9-24 describe the function selected by the FM bits and other pin mode bits for the multiplexed
pins.