Data Alignment Configurations - Motorola MC92603 Reference Manual

Data Alignment Configurations

received data is obtained, may be operated in five operating modes as described in
Table 3-4.
Table 3-4. MC92603 Receiver Operating Modes (Common Features/Characteristics)
Backplane 10- or 5-bit coded data modes—non-aligned
Backplane 10- or 5-bit coded data modes—aligned
Backplane 8- or 4-bit byte modes
GMII or RGMII compatible mode
TBI or RTBI compatible mode
The interface may be operated in the byte mode (8 bits) or in the 10-bit interface, TBI,
mode. Received data is a byte (8 bits) of uncoded data, when in the backplane byte or GMII
modes. In these modes, the internal 8B/10B decoder was used to decode data from the
received 10-bit character. Byte interface mode is enabled by negating TBIE low.
Received data is 10-bits of pre-coded data when in the 10-bit interface, TBI, mode. The
internal 8B/10B decoder is not used, and it is assumed that decoding is done externally. The
10-bit interface mode is enabled by asserting TBIE high.
The received data is presented on the interface RECV_x_7 through RECV_x_0 signals
when operating in the GMII or 8-bit backplane modes. In the 10-bit backplane or TBI
modes, RECV_x_ERR, RECV_x_DV become bits 9 and 8, respectively.
In the reduced interface operational modes, the receiver signals RECV_x_7 through
RECV_x_4 are not used and the 5th and 9th data bits are output on the RECV_x_DV signal.
With the reduced interface, data in the alignment FIFO is presented at the receiver interface
as double data rate (DDR), on the rising and falling edge of the appropriate receiver clock,
RECV_x_RCLK.
The receiver status and error reporting is coded onto the RECV_x_ERR, RECV_x_DV,
RECV_x_COMMA, and RECV_x_K signals.
3.5 Data Alignment Configurations
The receiver supports two modes of byte alignment as defined by the BSYNC signal.
Table 3-5 shows the settings to activate each mode.
Do not use non-aligned mode (BSYNC = low) in 8-bit modes.
The non-aligned mode is only valid if TBIE is high.
3-8
MC92603 Quad Gigabit Ethernet Transceiver Reference Manual
Operating Mode
Table 3-5. Byte Synchronization Modes
Byte Alignment Mode
Byte Aligned
Non-Aligned
NOTE
BSYNC COMPAT
Low Low
High Low
High Low
High High
High High
BSYNC
High
Low
TBIE
High
High
Low
Low
High
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