Laptop User Manual
3-52 Computer Group Literature Center Web Site
System Memory Controller (SMC)
3
Error_Address Register
ERROR_ADDRESS These bits reflect the value that corresponds to bits 0-28
of the PPC60x address bus when the SMC last logged an
error during a PowerPC access to SDRAM. They reflect
the value of the SCRUB ADDRESS counter if the error
was logged during a scrub cycle.
Scrub/Refresh Register
scb0, scb1 These bits increment every time the scrubber completes a
scrub of the entire SDRAM. When they reach binary 11,
they roll over to binary 00 and continue. These bits are
cleared by power-up reset.
swen
When set, swen allows the scrubber to perform write
cycles. When cleared, swen
prevents scrubber writes.
SCRUB_FREQUENCY
Determines the rate of scrubbing by setting the roll-over
count for the scrub prescale counter. Each time the SMC
performs a refresh burst, the scrub prescale counter
increments by one. When the scrub prescale counter
reaches the value stored in this register, it clears and
resumes counting starting at 0.
Address
$FEF80038
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
ERROR_ADDRESS
0
0
0
Operation
READ ONLY
R
R
R
Reset
0 P
X
X
X
Address
$FEF80040
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
scb0
scb1
0
0
0
0
0
swen
SCRUB FREQUENC
Y
Operation
R
R
R
R
R
R
R
R/W
READ ZERO READ ZERO READ/WRITE
Reset
0 P
0 P
X
X
X
X
X
0 P
X X $00 P