AN910 datasheet(37/51 Pages) STMICROELECTRONICS

37 / 51 page

37/51

ST7 AND ST9 PERFORMANCE BENCHMARKING

7.3.10 80C51 MCU core

On-chip/Off-chip buses

- on-chip buses

8/16-bit address bus

8-bit data memory bus

8-bit program memory bus

- off-chip buses

8/16-bit address bus

8-bit data/program memory bus

the two buses are multiplexed

the two buses are multiplexed with ports

Memory Spaces

Harvard organization

- linear data/program memory space

data memory space

64 kbytes

first 128-byte zero page

lowest 32-byte banked register space

16-byte bit addressable space

special function register space (logically separate)

128-byte special function register space

direct addressable only

program memory space

64 kbytes

first 128-byte zero page

first 24-byte interrupt vector table = 5 interrupts

Arithmetic Logic Unit

8-bit datapath

- 8-bit operations

- special functions

8x8 unsigned multiplication

48 cycles

16/8 unsigned division

48 cycles

Instruction processing

Standard

- sequential processing

Core internal buses

16-bit address bus, 8-bit data bus

(to be confirmed)

Instruction set

Cisc encoding

- CPI

12 cycles to 48 cycles

- average CPI

between 18 and 20 cycles

- IL

1 byte to 3 bytes

- average IL

between 1 and 2 bytes

- special addressing modes

16-bit addressing with data pointer register

stack pointer relative

- special instructions

exchange accumulator and register/direct byte

compare/decrement & branch like

bit test & bit clear & jump

memory-to-memory moves

direct to direct

direct to indirect

Programming model

Accumulator

- general registers

4 banks of eight 8-bit registers

they are mapped in data memory

- special function registers

one 8-bit accumulator

16-bit program counter

16-bit data pointer register

useable as two 8-bit registers

8-bit stack pointer

condition code register

peripheral registers

they are mapped in data memory

- multitasking capabilities

context switching with banked registers

+ / x

80C51 CPU

MOV A,(R1)

ADD

A,#A0

AN910 数据表(PDF) 37 Page - STMicroelectronics

AN910 数据表(HTML) 37 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

数据表下载