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Board Descriptions
A - 21
OKIOFFICE 44 Serv. Man., P/N 59276801
+5 V
IC1
X1
20 MHz
PWRDY-N
20 MHz
Initial Reset Circuit
Address bus
RES
XTAL
EXTAL
CPU
Port C
Data/Address bus
Port A
Port B
CK
(PC1/PC2)
M
D-motor
Clutch
Related Signals of CPU (Figure A3.1.1)
A3.1
R44 Circuit Diagram
A3.1.1
R44 Circuit Diagram)
1.
Block diagram
The circuit diagram consists of the CPU, crystal oscillator circuit and reset signal generator.
Figure A3.1.1 shows the block diagram of CPU and the peripheral circuits.
2.
Function
1)
Crystal oscillator circuit
X1 is a 20 MHz crystal oscillator. The output wave is fed to the CPU through pin 73 and
74.
CLK (20 MHz) signal output from pin 71 is used as the system clock and output to IC2.
(IOGA3: input/output gate array).
2)
CPU
CPU controls the following functions in addition to the basic processor.
•
DMA (Direct Memory Access) control
•
Interrupt procedure control
•
A/D converter
•
Bus state control
•
Programmable pattern control
•
16 bit integrated timer pulse unit (ITU)
•
Timing pattern control (TPC)
•
Serial communication interface (SCI)
Summary of Contents for OKIOFFICE 44
Page 2: ...All specifications are subject to change without notice Service Manual OKIOFFICE 44 59276801...
Page 135: ...Disassembly 4 6 OKIOFFICE 44 Service Manual P N 59276801 Whole Unit Picture FX048 CP4 1 Fig 01...
Page 329: ...Illustrated Parts List D 6 OKIOFFICE 44 Service Manual P N 59276801 Section 2 Printer Unit...
Page 331: ...Illustrated Parts List D 8 OKIOFFICE 44 Service Manual P N 59276801 Section 3 Operator Panel...
Page 351: ...Illustrated Parts List D 28 OKIOFFICE 44 Service Manual P N 59276801 Section 12 Cables...
Page 357: ...Board Layout E 2 OKIOFFICE 44 Service Manual P N 59276801 MEM eps E 2 MEM PCB...
Page 358: ...Board Layout E 3 OKIOFFICE 44 Service Manual P N 59276801 TEL U eps E 3 TEL U PCB...
Page 359: ...Board Layout E 4 OKIOFFICE 44 Service Manual P N 59276801 Hook eps E 4 Hook PCB...
Page 388: ...OKIOFFICE 44 Service Manual Part Number 59276801 Printed in the USA...