Oki ML420 - Parts Identification: Top Feed

42113901TH01 Rev.3 11 /
Oki Data CONFIDENTIAL
MPU CLOCK
A0~A17
PG-N
PSEN-N
D0~D15
CSO
PSEN
CE
OE
PG-N
PSEN-N
D0~D15
A0~A17
MPU ROM
(2) Program ROM
This is a 256 × 16 bits (4M bit) EPROM or MASK ROMwith the control program for the
printer stored. The MPU executes instructions under this program.
The program ROM is assigned to the program memory area of the MPU and is fetched
by the PSEN-N signal of the MPU.
The following shows the operation of the memory access.