
Serial Communication Controllers (SCCs)
7-240
MC68360 USER’S MANUAL
Figure 7-67. Connecting the QUICC to Ethernet
The following pins take on new meanings when the Ethernet protocol is selected for the
SCC:
1. Transmit Enable (TENA). The SCC’s RTS pin changes to become TENA when the
SCC is configured for Ethernet operation. The polarity of TENA is active high; where-
as, the polarity of RTS is active low.
2. Receive Enable (RENA). The SCC’s CD pin changes to become RENA when the SCC
is configured for Ethernet operation. The polarity of RENA is active high; whereas, the
polarity of CD is active low.
3. Collision (CLSN). The SCC’s CTS pin changes to become CLSN when the SCC is
configured for Ethernet operation. The polarity of CLSN is active high; whereas, the
polarity of CTS is active low.
NOTE
The carrier sense signal is often referred to in Ethernet descrip-
tions, because it defines whether the LAN is currently in use.
Carrier sense is defined as RENA ORed with CLSN.
The EEST has similar names for its connection to the seven basic QUICC pins. In addition,
the EEST contains a loopback pin to allow the QUICC to perform external loopback testing.
This can be controlled by any available parallel I/O pin on the QUICC.
QUICC
RJ-45
SCC
TXD
TENA (RTS)
TCLK (CLKx)
RXD
RENA (CD)
RCLK (CLKx)
CLSN (CTS)
PARALLEL I/O
TX
TENA
TCLK
RX
RENA
RCLK
CLSN
LOOP
D-15
TWISTED PAIR
AUI
PASSIVE
EEST
MC68160
PREAMBLE
FRAME
CHECK
SEQUENCE
START
FRAME
DELIMITER
DATA
7 BYTES
1 BYTE
46–1500 BYTES
DEST.
ADDR.
SOURCE
ADDR.
6 BYTES
2 BYTES
TYPE/
LENGTH
6 BYTES
4 BYTES
STORED IN TRANSMIT BUFFER
STORED IN RECEIVE BUFFER
NOTE: Short transmit frames are padded automatically by the QUICC.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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