Oki ML490 Maintenance Manual page 12

(3) RAM
The RAM is CMOS dynamic RAM with 256K
as receiving buffer, printing buffer, DLL buffer and working buffer).
The following shows the examples of the memory access operation.
Clockout*
A0~A8
RAS-N
VCAS-N
LCAS-N
RD-N
D0~D15
(Read)
WR-N
D0~D15
(Write)
* Clockout is provided when the original excitation is selected.
42114101 Rev.1
MPU
A0~A8
RAS-N
P03
CAS-N
CS1
ALS139
WRH-N
P11
WRL-N
ALS11
WRL
D0~D15
RD-N
RD
T1 T2
16-bit bus, Word instruction
16-bit (4M bit), and used as buffers (such
RAM
RAS
UCAS-N
UCAS
LCAS-N
LCAS
WR-N
WE
OE
T3 T4
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