Cpu I, Cpu Ii; System Configuration - Sharp PC-1211 Service Manual

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• The CPU I functions to read key-in data or read the instruction to be executed from the RAM,
and decides what is to be done for the control of arithmetical operation (i.e. control of
arithmetic sequence, memorizing of arithmetical data, and its readout), or interprete the syntax
of the BASIC instruction for deciding what is to be executed, or determines and prepares the
information to be displayed, but the CPU I does not perform any execution by itself.
It
only
arranges the data and information in proper sequence and acts to provide instruction code to the
CPU II via the buffer. On the other hand, the CPU II constantly receives execution instructions
from the CPU I via the transfer buffer and executes operation against each of instructions or
sometimes performs to exchange data depending on the situation. Although it shares major part
of execution in term of execution, it performs some kinds of auxiliary CPU when looked in the
view that it does not perform any decision by itself.
Clock stop Clock stop control
I
Power shut off control
I
Power off
Display processing routine
Input buffer
Computational result
Error
Arithmetic routine
Character generator
Cassette routine
Print routine
Buzzer
Recognition of printer
Key input routine
Acknowledgement of the remaining
program
One instruction to one program step
incorporation
Interpreter:
Program execute statement
Cassette control statement
Command statement
Printer control
Execution of manual operation
CPU
II
CPUI
These CPUs are provided with internal ROM, and each of CPUs shares the following assignments:
2-1. CPU I, CPU II
System configuration (see the system block diagram)
System of this unit consists of the following components:
1) CPU I (SC43157) x 1
2) CPU II (SC43178) x 1
3) 4K-bit RAM (TC5514P x 3)
4) Display chip (SC43125 x 3, with built-in RAM)
5) 2AND gate (TC401 l UBP x 1)
6) 2AND 20R (TC4019BP x 1)
7) Inverter (TC4069BP x 1)
8) Quard Analog Switch Multiplexer (TC4066BP)
9) LCD (24-digit FEM dot LCD)
10) Key
11) Crystal (CSB2560)
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