AT43USB326 datasheet(26/102 Pages) ATMEL

26 / 102 page

AT43USB326

3313D–USB–04/06

External Interrupts

While in the suspend state, the depression of any key will trigger a resume interrupt. This is

the only available external interrupt in the AT43USB326.

Interrupt

Response Time

The interrupt execution response for all the enabled AVR interrupts is 4 clock cycles minimum.

4 clock cycles after the interrupt flag has been set, the program vector address for the actual

interrupt handling routine is executed. During this 4 clock cycle period, the Program Counter (2

bytes) is pushed onto the Stack, and the Stack Pointer is decremented by 2. The vector is nor-

mally a jump to the interrupt routine, and this jump takes 3 clock cycles. If an interrupt occurs

during execution of a multi-cycle instruction, this instruction is completed before the interrupt is

served.

A return from an interrupt handling routine (same as for a subroutine call routine) takes 4 clock

cycles. During these 4 clock cycles, the Program Counter (2 bytes) is popped back from the

Stack, the Stack Pointer is incremented by 2, and the I flag in SREG is set. When the AVR

exits from an interrupt, it will always return to the main program and execute one more instruc-

tion before any pending interrupt is served.

AT43USB326 데이터시트(PDF) 26 Page - ATMEL Corporation