Atmel AVR User Manual

43. CLR – Clear Register
43.1. Description
Clears a register. This instruction performs an Exclusive OR between a register and itself. This will clear
all bits in the register.
Operation:
(i) Rd ← Rd ⊕ Rd
Syntax: Operands: Program Counter:
(i) CLR Rd 0 ≤ d ≤ 31 PC ← PC + 1
16-bit Opcode: (see EOR Rd,Rd)
0010 01dd dddd dddd
43.2. Status Register (SREG) and Boolean Formula
I T H S V N Z C
– – – 0 0 0 1 –
S 0
Cleared.
V 0
Cleared.
N 0
Cleared.
Z 1
Set.
R (Result) equals Rd after the operation.
Example:
clr r18 ; clear r18
loop: inc r18 ; increase r18
...
cpi r18,$50 ; Compare r18 to $50
brne loop
Words 1 (2 bytes)
Cycles 1
Atmel AVR Instruction Set Manual [OTHER]
Atmel-0856L-AVR-Instruction-Set-Manual_Other-11/2016
71

Atmel AVR Specifications

General

Architecture	8-bit RISC
SRAM	Up to 16 KB
Clock Speed	Up to 20 MHz
Operating Voltage	1.8V to 5.5V
ADC	10-bit ADC
Communication Interfaces	SPI, I2C, USB
Packages	DIP, SOIC, QFN
Special Features	Watchdog Timer
Flash Memory	1KB to 256KB
EEPROM	64B to 4KB