Download  Print this page

HP 13255 Manual page 15

Memory controller module
Hide thumbs

Advertisement

13255
Memory Controller
13255-91252/13
REV
JUN-23-81
3.9.5
MEMRAS is
ANDed with BOARD SELECT the ORed with RFSH RAS to
torm the
row address strobe signal to the memory array (Ul4-11).
CAS is used to
latch data out;
in addition,
CAS is used to determine which module
ot
memory is being addressed.
This is accomplished with a 74LS138, 3 to 8
line decoder.
This decoder uses ADDR18 and ADDR17 at the address pins
(Ul7-2,1)
to
determine
which
ot
the tour memory modules is being ac-
cessed.
When the
decoder is enabled by
BOARD SELECT,
a CAS at
the
other enable input (U17-5) produces a similar pulse at one
ot
four out-
puts;
this pulse is used as the column address strobe for the accessed
module.

Advertisement

Table of Contents
loading

  Also See for HP 13255

  Related Manuals for HP 13255