Rainbow-electronics ATmega8515L Instrukcja Użytkownika Pobierz pdf (Strona 9)

ATmega8515(L)

2512A–AVR–04/02

• Bit0–C:CarryFlag

The Carry Flag C indicates a carry in an arithmetic orlogic operation. See the“Instruc-

tion Set Description” fordetailed information.

General Purpose

TheRegisterFileis optimizedfor the AVR Enhanced RISC instruction set. Inorder to

achieve the requiredperformanceandflexibility, the following input/output schemes are

supportedbythe RegisterFile:

• One 8-bit output operand and one 8-bit resultinput

•Two8-bit output operands and one 8-bit resultinput

•Two8-bit output operands and one 16-bit resultinput

• One 16-bit output operand and one 16-bit resultinput

Figure4shows the structureof the 32 generalpurpose working registers in the CPU.

Figure 4. AVR CPUGeneral Purpose Working Registers

Mostof theinstructions operatingonthe RegisterFile have directaccess to all registers,

and mostof them are single cycleinstructions.

AsshowninFigure4, each register is alsoassigned a data memory address, mapping

them directly into the first 32 locations of theuserData Space. Although not being phys-

ically implemented asSRAMlocations, this memory organization provides great

flexibility in access of the registers, as the X-, Y-, andZ-pointer Registers can be set to

index anyregister in the file.

7 0Addr.

R0 $00

R1 $01

R2 $02

…

R13$0D

General R14 $0E

PurposeR15$0F

Working R16$10

Registers R17$11

…

R26$1A X-registerLowByte

R27$1BX-registerHighByte

R28 $1CY-registerLowByte

R29$1DY-registerHighByte

R30 $1EZ-registerLowByte

R31 $1FZ-registerHighByte

1 2 3 4 5 6 7 8 9 10 11 12 13 14 ... 222 223

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Rainbow-electronics ATmega8515L Instrukcja Użytkownika Strona 9