HP 9020 - Page 50

2-24 Theory of Operation
Error Detection, Correction, and Memory Healing
Error detection and correction is the same for the 256K RAM and the 512K RAM. The only
differences are
in the physical memory address in the healer CAM. The chip select portion of the
address uses eight chip select lines instead of four.
HEALER CAM
(ADDRESS)
0 31
0
I
1 0
I
11
•
•
•
1
31
......
/
......
......
/
/
( 0
Itt
r",--., .... ---...,
l-HEALED LOCATION
X-DON'T CARE
HEALER RAM
(DATA)
31 32
39
DATA
CHECK 1 0
BITS
•
•
•
......
......
......
......
......
......
......
......
......
......
29 30
MEMORY ADDRESS~
BITS) ~
1 1
1
31
J
Figure 2-15. 512K Memory Healing