MOTOROLA
Chapter 6. Test Features
6-5
System Accessible Test Modes
6.2.2
BIST Sequence System Test with External Loopback
Modes
The MC92603’s transmitter has an integrated, 23rd order, pseudo-noise (PN) pattern
generator. Stimulus from this generator may be used for system testing. The receiver, has a
23rd order signature analyzer that is synchronized to the incoming PN stream and may be
used to count code group mismatch errors relative to the internal PN reference pattern.
This implementation of the 23-bit PN generator and analyzer uses the following
polynomial:
f = 1 + x
5
+ x
23
The total mismatch error count is reset to zero on entering BIST mode. The count is updated
continuously while in BIST mode. The value of the count is presented on the receiver
interface signals, RECV_x_7–RECV_x_0, which make up the 8-bit error count. The value
of the count is sticky in that the count will not wrap to zero on overflow, but rather, stays at
the maximum count value (11111111).
NOTE
An error counter is maintained in MDIO RA 18 for each
specific channel in all BIST test modes. See Chapter 4,
“Management Interface (MDIO),” for details.
The RECV_x_ERR, RECV_x_DV, and RECV_x_COMMA signals, as interpreted and
shown in Table 6-5, have special meaning in this test mode. They report the status of the
receiver and PN analysis logic.
The BIST sequence makes use of the 8B/10B encoder/decoder. Therefore, this test mode
overrides the setting on the TBIE signal and forces byte interface mode. Additionally, the
BIST sequence requires that a normal byte alignment mode be used. The setting of BSYNC
is overridden, forcing the device into the byte aligned mode, which forces BSYNC high
internally.
Table 6-5. BIST Error Codes
RECV_x_ERR
RECV_x_DV
RECV_x_COMMA
Description
Low
Low
Don’t care
Not byte/word sync. The receiver is in start-up or has lost byte
alignment and is searching for alignment.
Low
High
Low
BIST running. No PN mismatch this code group.
Low
High
High
BIST running. This code group is a COMMA code group.
High
Low
Don’t care
Receiver byte/word synchronized. PN analyzer is not locked.
High
High
Don’t care
BIST running. PN mismatch error for this code group.
Summary of Contents for MC92603
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