ST7260E1 STMicroelectronics, ST7260E1 Datasheet - Page 101

• Manufacturer Part Number: ST7260E1
• Description: LOW SPEED USB 8-BIT MCU FAMILY WITH UP TO 8K FLASH/ROM AND SERIAL COMMUNICATION INTERFACE (SCI)
• Manufacturer: STMicroelectronics

Specifications of ST7260E1

• 4 Or 8 Kbytes Program Memory: high density Flash (HDFlash), or FastROM with readout and write protection

ST7260xx
15
15.1
Table 48.
Inherent
Immediate
Short
Long
No Offset
Short
Long
Short
Long
Mode
Direct
Direct
Direct
Direct
Direct
Indirect
Indirect
Instruction set
ST7 addressing modes
The ST7 Core features 17 different addressing modes which can be classified in 7 main
groups:
Table 47.
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 subdivided in two sub-modes
called long and short:
●
●
The ST7 Assembler optimizes the use of long and short addressing modes.
ST7 addressing mode overview
Inherent
Immediate
Direct
Indexed
Indirect
Relative
Bit operation
Long addressing mode is more powerful because it can use the full 64 Kbyte address
space, however it uses more bytes and more CPU cycles.
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 instructions use short addressing modes only (CLR, CPL, NEG,
BSET, BRES, BTJT, BTJF, INC, DEC, RLC, RRC, SLL, SRL, SRA, SWAP)
Indexed ld A,(X)
Indexed ld A,($10,X)
Indexed ld A,($1000,X)
Addressing mode groups
Addressing mode
nop
ld A,#$55
ld A,$10
ld A,$1000
ld A,[$10]
ld A,[$10.w]
Syntax
00..FF
0000..FFFF
00..FF
00..1FE
0000..FFFF
00..FF
0000..FFFF
Destination/
source
nop
ld A,#$55
ld A,$55
ld A,($55,X)
ld A,([$55],X)
jrne loop
bset
byte,#5
00..FF
00..FF
address
Pointer
byte
word
Pointer
Example
size
+ 0
+ 1
+ 1
+ 2
+ 0 (with X register)
+ 1 (with Y register)
+ 1
+ 2
+ 2
+ 2
Instruction set
Length
(bytes)
101/139