AT86RF401E ATMEL [ATMEL Corporation], AT86RF401E Datasheet - Page 19

• Manufacturer Part Number: AT86RF401E
• Description: Smart RF Wireless Data Microtransmitter
• Manufacturer: ATMEL [ATMEL Corporation]

General-purpose
Register File
1424F–RKE–12/03
Figure 8 shows the structure of the 32 general-purpose working registers in the CPU.
Figure 8. 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 9, each register is also assigned a data memory address, mapping
the registers directly into the first 32 locations of the user data space. Although not being
physically 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.
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
X-register high byte
Z-register high byte
Y-register high byte
X-register low byte
Z-register low byte
Y-register low byte
AT86RF401
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