ST72521AR7TC View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST72521AR7TC

8-BIT MCU WITH NESTED INTERRUPTS, FLASH, 10-BIT ADC, FIVE TIMERS, SPI, SCI, I2C, CAN INTERFACE

STMicroelectronics 

ST72521M/R/AR

11 INSTRUCTION SET

11.1 ST7 ADDRESSING MODES

The ST7 Core features 17 different addressing

modes which can be classified in 7 main groups:

Addressing Mode

Inherent

Immediate

Direct

Indexed

Indirect

Relative

Bit operation

Example

nop

ld A,#$55

ld A,$55

ld A,($55,X)

ld A,([$55],X)

jrne loop

bset byte,#5

The ST7 Instruction set is designed to minimize

the number of bytes required per instruction: To do

so, most of the addressing modes may be subdi-

vided in two sub-modes called long and short:

– Long addressing mode is more powerful be-

cause it can use the full 64 Kbyte address space,

however it uses more bytes and more CPU cy-

cles.

– Short addressing mode is less powerful because

it can generally only access page zero (0000h -

00FFh range), but the instruction size is more

compact, and faster. All memory to memory in-

structions use short addressing modes only

(CLR, CPL, NEG, BSET, BRES, BTJT, BTJF,

INC, DEC, RLC, RRC, SLL, SRL, SRA, SWAP)

The ST7 Assembler optimizes the use of long and

short addressing modes.

Table 27. ST7 Addressing Mode Overview

Mode

Inherent

Immediate

Syntax

nop

ld A,#$55

Destination

Pointer

Address

(Hex.)

Pointer Size

(Hex.)

Length

(Bytes)

+0

+1

Short

Direct

ld A,$10

00..FF

+1

Long

Direct

ld A,$1000

0000..FFFF

+2

No Offset Direct Indexed ld A,(X)

00..FF

+0

Short

Direct Indexed ld A,($10,X)

00..1FE

+1

Long

Direct Indexed ld A,($1000,X) 0000..FFFF

+2

Short

Indirect

ld A,[$10]

00..FF

00..FF

byte

+2

Long

Indirect

ld A,[$10.w]

0000..FFFF 00..FF

word

+2

Short

Indirect Indexed ld A,([$10],X)

00..1FE

00..FF

byte

+2

Long

Indirect Indexed ld A,([$10.w],X) 0000..FFFF 00..FF

word

+2

Relative

Direct

jrne loop

PC+/-127

+1

Relative

Bit

Bit

Indirect

Direct

Indirect

jrne [$10]

PC+/-127 00..FF

byte

+2

bset $10,#7

00..FF

+1

bset [$10],#7

00..FF

00..FF

byte

+2

Bit

Direct Relative btjt $10,#7,skip 00..FF

+2

Bit

Indirect Relative btjt [$10],#7,skip 00..FF

00..FF

byte

+3

148/199

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