Scan Path Operation - Motorola MC68838 User Manual

Media access controller
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Register
TX_Control
My Short Address
My Long Address A
My Long Address B
My Long Address C
Target Request Time Register
TVX, TRT Initial Timer Parameter Register
Interrupt Mask Register A
Interrupt Mask Register B
RC_Control (Run BIST)
BIST Result Revision A MAC
BIST Result Revision C MAC
NOTE: All values are hexadecimal.
BIST Test 3 is very sensitive to different implementations. If
your BIST signature for Test 3 differs from the one listed here,
please use that value if the chip is otherwise functional.

10.2 SCAN PATH OPERATION

Boundary scanning allows the user to shift an arbitrary bit pattern into the MAC to be used
for the corresponding input or output signal and to shift out the values of these signals
while holding the clock. The boundary scan chain includes every signal on the MAC
except MATCH , the test signals, and the clocks.
Although boundary scanning complements BIST, which does not test these latches, the
main purpose of this test mode is for board testing. In this mode, the I/O latches of the
various chips on the board are linked into a large scan chain. By serially shifting data into
the scan chain (boundary scan serial test mode), then clocking the data in parallel (normal
or boundary scan parallel test mode), and finally serially shifting the data out, the I/O
latches and interconnections between the various chips can be tested on a PC board.
10-2
Table 10-1. BIST Register Values
Address
Run BYTCLK until BIST_Done is indicated by MACINT assertion
MC68838 USER'S MANUAL
Test 1 Value
1
0200
10
7777
11
AAAA
12
BBBB
13
CCCC
14
FF00
15
AACC
2
0000
3
0000
0
88C4
2A
6148
2A
9FA2
NOTE
Test 2 Value
Test 3 Value
82FF
13FF
8888
137F
5555
37F1
4444
7F13
3333
F137
00FF
FEC8
5533
F0FC
0000
0000
0000
0000
F127
A414
0E9C
DED9
7FB6
E93E
MOTOROLA

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