Atmel AVR User Manual

108. SEI – Set Global Interrupt Flag
108.1. Description
Sets the Global Interrupt Flag (I) in SREG (Status Register). The instruction following SEI will be
executed before any pending interrupts.
Operation:
(i) I ← 1
Syntax: Operands: Program Counter:
(i) SEI None PC ← PC + 1
16-bit Opcode:
1001 0100 0111 1000
108.2. Status Register (SREG) and Boolean Formula
I T H S V N Z C
1 – – – – – – –
I 1
Global Interrupt Flag set.
Example:
sei ; set global interrupt enable
sleep ; enter sleep, waiting for interrupt
; note: will enter sleep before any pending interrupt(s)
Words 1 (2 bytes)
Cycles 1
Atmel AVR Instruction Set Manual [OTHER]
Atmel-0856L-AVR-Instruction-Set-Manual_Other-11/2016
161

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