at90ls8535-8mi ATMEL Corporation, at90ls8535-8mi Datasheet - Page 9

• Manufacturer Part Number: at90ls8535-8mi
• Description: 8-bit Microcontroller With 8k Bytes In-system Programmable Flash
• Manufacturer: ATMEL Corporation

General-purpose
Register File
1041H–11/01
memory. The different interrupts have priority in accordance with their interrupt vector
position. The lower the interrupt vector address, the higher the priority.
Figure 6 shows the structure of the 32 general-purpose working registers in the CPU.
Figure 6. AVR CPU General-purpose Working Registers
All the register operating instructions in the instruction set have direct and single-cycle
access to all registers. The only exception is the five constant arithmetic and logic
instructions SBCI, SUBI, CPI, ANDI and ORI between a constant and a register and the
LDI instruction for load immediate constant data. These instructions apply to the second
half of the registers in the register file (R16..R31). The general SBC, SUB, CP, AND,
and OR and all other operations between two registers or on a single register apply to
the entire register file.
As shown in Figure 6, each register is also assigned a data memory address, mapping
them directly into the first 32 locations of the user Data Space. Although not being phys-
ically implemented as SRAM locations, this memory organization provides great
flexibility in access of the registers, as the X-, Y-, and Z-registers can be set to index any
register in the file.
Registers
Purpose
General
Working
7
R13
R14
R15
R16
R17
R26
R27
R28
R29
R30
R31
R0
R1
R2
…
…
0
Addr.
$0D
$0E
$1A
$1B
$1C
$1D
$1E
$00
$01
$02
$0F
$10
$11
$1F
AT90S/LS8535
X-register high byte
Y-register high byte
Z-register high byte
X-register low byte
Y-register low byte
Z-register low byte
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