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Programming Model
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3-53
3
Data Parity Error Logger Register
The Data Parity Error Logger and Data Parity Error Address and Data
registers are much like the Error Logger and Error Address registers in that
it is normal for status to differ between the upper and lower Falcons. This
is due to the fact that each Falcon is connected to its own half of the 60x
data bus and data parity bus. The upper Falcon can log parity error during
a cycle and the lower Falcon not, or vice-versa. Or they can both log a
parity error during the same cycle and have the attributes of the errors
differ.
Because of the above, software needs to monitor both the upper and lower
Falcon’s Data Parity Error Logger, Data Parity Error Address and Data
Parity Error Data Registers. This includes checking the dpelog bit from the
upper Falcon and from the lower Falcon. When the upper Falcon logs an
error, it updates its attribute bits (dpe0-3, DATA PARITY ERROR
ADDRESS, and DATA PARITY ERROR DATA) to match the results
of the read cycle for the upper 60x data bus. When the lower Falcon logs
an error, it updates its attribute bits to match the results of the read cycle
for the lower 60x data bus.
While the logging of data parity errors by one Falcon in a pair does not
affect the logging of data parity errors by the other, writing to the Data
Parity Error Logger control bits does affect both Falcons. This is of
particular interest as regards the dpelog bit. Writing a one to the dpelog bit
clears the dpelog bit for both the upper and lower Falcons. Because of this,
Address
$FEF80068
Bit
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Name
dp
el
o
g
0
0
d
p
e_
tt0
d
p
e_
tt1
d
p
e_
tt2
d
p
e_
tt3
d
p
e_
tt4
0
0
0
0
d
p
e_
dp0
d
p
e_
dp1
d
p
e_
dp2
d
p
e_
dp3
0
0
0
0
0
0
d
p
e_
ckall
dp
e_
m
e
GWDP
Operation
R/C
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R/W R/W
READ/WRITE
Reset
0 P
X
0 P
0 P
0 P
0 P
0 P
X
X
X
X
0 P
0 P
0 P
0 P
X
X
X
X
X
X
0 PL 0 PL
0 PL