ANDed with BOARD SELECT the ORed with RFSH RAS to
row address strobe signal to the memory array (Ul4-11).
CAS is used to
latch data out;
CAS is used to determine which module
memory is being addressed.
This is accomplished with a 74LS138, 3 to 8
This decoder uses ADDR18 and ADDR17 at the address pins
the tour memory modules is being ac-
decoder is enabled by
a CAS at
other enable input (U17-5) produces a similar pulse at one
this pulse is used as the column address strobe for the accessed