Filter
Top Products
Chapter 2 CPU Basics
II - 2
Overview
2-1 Overview
The MN101C CPU has a flexible optimized hardware configuration. It is a high speed CPU with a simple
and efficient instruction set. Specific features are as follows:
Table 2-1-1 Basic Specifications
1. Minimized code sizes with instruction lengths based on 4-bit increments
The series keeps code sizes down by adopting a basic instruction length of one byte and variable
instruction lengths based on 4-bit increments.
2. Minimum execution instruction time is one system clock cycle.
3. Minimized register set that simplifies the architecture and supports C language
The instruction set has been determined, depending on the size and capacity of hardware, after
an analysis of embedded application programing code and creation code by C language compiler.
Therefore, the set is simple instruction using the minimal register set required for C language
compiler. [
"MN101C LSI User's Manual" (Architecture Instructions) ]
Data : 8-bit x 4
Address : 16-bit x 2
PC : 19-bit
PSW : 8-bit
SP : 16-bit
Number of instructions 37
Addressing modes 9
Basic portion : 1 byte (min.)
Extended portion : 0.5-byte x n
(0
<
n
<
9)
Instruction execution Min. 1 cycle
Inter-register operation Min. 2 cycles
Load / store Min. 2 cycles
Conditional branch 2 to 3 cycles
Pipeline 3-stage (instruction fetch, decode, execution)
Address space 256 KB (max. 64 KB for data)
Address 18-bit (max.)
Data 8-bit
Minimum bus cycle 1 system clock cycle
Interrupt Vector interrupt 3 interrupt levels
STOP mode
HALT mode
Low-power
dissipation mode
Six registers
Other
Instruction length
Structure
Instructions
Basic performance
External bus
Load / store architecture