Rainbow-electronics ATmega8515L Bedienungsanleitung PDF herunterladen (Seite 44)

44

ATmega8515(L)

2512A–AVR–04/02

Power-on Reset APower-on Reset (POR)pulseis generatedbyan On-chipdetection circuit. The detec-

tion level isdefined in Table18.ThePORis activatedwhenever V

CC

isbelow the

detection level.ThePOR circuit can beused to trigger the Start-up Reset, aswell as to

detectafailureinsupply voltage.

APower-on Reset (POR)circuit ensures that the deviceisreset from Power-on. Reach-

ing thePower-on Reset threshold voltage invokes the delaycounter, which determines

howlong the deviceiskeptinRESETafter V

CC

rise. TheRESET signal is activated

again,without anydelay, when V

CC

decreasesbelow the detection level.

Figure 22. MCU Start-up, RESET

Tied to V

CC

Figure 23. MCU Start-up, RESET ExtendedExternally

V

RESET

TIME-OUT

INTERNAL

RESET

t

TOUT

V

POT

V

RST

CC

RESET

TIME-OUT

INTERNAL

RESET

t

TOUT

V

POT

V

RST

V

CC

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