Motorola MC92603, Reference Manual

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MOTOROLA Chapter 3. Receiver 3-23
Backplane Applications Modes (COMPAT = Low)
RECV_x_ERR is high, the state of the RECV_x_7–RECV_x_0 signals are decoded to
determine the error condition. Table 3-15 describes the error codes and their meaning.
The receiver interface is always timed to the output clock, RECV_x_RCLK. This clock
may be derived from the receiver’s recovered clock or to the reference clock depending on
the state of the RCCE signal as previously discussed.
3.8.2 10-Bit Mode (Coded Data)
Backplane 10-bit mode is enabled by asserting TBIE high and negating COMPAT low, as
shown in Table 3-15.
Received data is 10 bits of coded data. The internal 8B/10B decoder is bypassed. Receiver
data is presented on the signals: RECV_x_ERR, RECV_x_DV, and
RECV_x_7–RECV_x_0 (making up bits 9–0, respectively).
The RECV_x_COMMA is asserted high whenever the 10-bit code group is 1 of the 3
COMMA code groups.
Table 3-15. Receiver Interface Error and Status Codes
(Backplane Byte Mode)
RECV_x_
ERR
RECV_x_
DV
RECV_x_K
RECV_x_
COMMA
RECV_x_
[7:0]
Priority
1
1
The priority column shows the error that is reported if multiple errors occur at the same time. The lower
priority-numbered errors are reported first.
Description
Low Low Don’t care Don’t care Don’t care Undefined for backplane byte mode
Low High Low Don’t care Data 9 Normal operation, valid data code
group received.
Low High High Low Data 8 Normal operation, special code
group (non-COMMA) detected.
Low High High High Data 7 Normal operation (COMMA
detected)
High Don’t care Don’t care Don’t care 0x10 6 Disparity error: The 8B/10B decoder
detected a disparity error.
High Don’t care Don’t care Don’t care 0x08 5 Code error: The 8B/10B decoder
detected an illegal code group.
High Don’t care Don’t care Don’t care 0x04 3 Overrun
High Don’t care Don’t care Don’t care 0x02 3 Underrun
High Don’t care Don’t care Don’t care 0x01 2 Not word sync: The receiver is byte
synchronized but has not achieved
or has lost word alignment and is
searching for alignment.
High Don’t care Don’t care Don’t care 0x00 1 Not byte sync: The receiver is in
start-up or has lost byte alignment
and is searching for alignment.