Oki Microline 3321

42089201TH Rev.4 11 /
Oki Data CONFIDENTIAL
(2) Program ROM
This is a 256K/512K/1024K × 16 bits (4/8/16M bit) MASK ROM or FLASH ROM with 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 signal of the MPU.
The following shows the operation of the memory access.
MPU CLOCK
A0~A17/A18/A19
PG-N
PSEN-N
D0~D15
Program Program Program
IN IN IN
CSO
PSEN
CE
OE
PG-N
D0~D15
A0~A17/A18/A19
MPU ROM