ST72361AR4-Auto datasheet(34/279 Pages) STMICROELECTRONICS

34 / 279 page

Central processing unit

ST72361xx-Auto

34/279

Doc ID 12468 Rev 3

Central processing unit

4.1

Introduction

This CPU has a full 8-bit architecture and contains six internal registers allowing efficient

8-bit data manipulation.

4.2

Main features

●

Enable executing 63 basic instructions

●

Fast 8-bit by 8-bit multiply

●

17 main addressing modes (with indirect addressing mode)

●

Two 8-bit index registers

●

16-bit stack pointer

●

Low power HALT and WAIT modes

●

Priority maskable hardware interrupts

●

Non-maskable software/hardware interrupts

4.3

CPU registers

The six CPU registers shown in Figure 8 are not present in the memory mapping and are

accessed by specific instructions.

4.3.1

Accumulator (A)

The Accumulator is an 8-bit general purpose register used to hold operands and the results

of the arithmetic and logic calculations and to manipulate data.

4.3.2

Index registers (X and Y)

These 8-bit registers are used to create effective addresses or as temporary storage areas

for data manipulation. (The Cross-Assembler generates a precede instruction (PRE) to

indicate that the following instruction refers to the Y register.)

The Y register is not affected by the interrupt automatic procedures.

4.3.3

Program counter (PC)

The program counter is a 16-bit register containing the address of the next instruction to be

executed by the CPU. It is made of two 8-bit registers PCL (Program Counter Low which is

the LSB) and PCH (Program Counter High which is the MSB).

ST72361AR4-Auto Datenblatt(PDF) 34 Page - STMicroelectronics

ST72361AR4-Auto Datenblatt(HTML) 34 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datenblatt Download

Link URL