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Communication Processor Module
16.9.22.8 CONFIGURING THE SCCx ETHERNET PARAMETERS. You can configure a
serial communication controller to operate in Ethernet mode by setting the MODE field in the
general SCCx mode low register (GSMR_L). The receive errors are reported in the RX
buffer descriptor and the transmit errors are reported in the TX buffer descriptor. Several
fields in the GSMR_H and GSMR_L must be programmed to special values for Ethernet.
You must program the data synchronization register (DSR) using the table below. The
GSMR_L programs the first six bytes of the preamble and the SYN1 field of the DSR
programs the seventh byte (0x55) of the preamble. Program the 1-byte start delimiter with
the value 0xD5 in the SYN2 field of the DSR. Refer to Section 16.9.2 The General SCCx
Mode Registers for more information.
DSR
BIT
0
1
2
FIELD
RESET
0
1
1
R/W
ADDR
SYN2—Synchronization 2
This field represents the start frame delimiter for an Ethernet frame. You must set this field
to 0xD5.
SYN1—Synchronization 1
This field represents the seventh byte of the preamble for the Ethernet frame. You must set
this field to 0x55.
16.9.22.9 SCCx ETHERNET COMMANDS. You can program the CPM command register
(CPCR) with the following commands to transmit data. See Section 16.2.6.1 CPM
Command Register for additional information.
Note: Before issuing a CPM reset (RST bit in the CPCR), configure the TENA pin as
an input.
• STOP TRANSMIT —When used with the SCCx Ethernet controller, this command
violates a specific behavior of an Ethernet/IEEE 802.3 station. It must not be used.
16-330
3
4
5
6
7
SYN2
1
1
1
1
0
R/W
(IMMR & 0xFFFF0000) + 0xA2E
MPC823e REFERENCE MANUAL
8
9
10
11
12
SYN1
0
1
1
1
1
R/W
13
14
15
1
1
0
MOTOROLA
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