![]() ![]() The MCU is reset when a low level is present on the RESET pin for longer than the minimum pulse length. The MCU is reset when the supply voltage is below the power-on reset threshold (VPOT). The Atmel ATmega328P has four sources of reset:.The different selections for the delay period are presented in Section 8.2 “Clock Sources” on page 25 (see the datasheet). The time-out period of the delay counter is defined by the user through the SUT and CKSEL fuses. This allows the power to reach a stable level before normal operation starts. This does not require any clock source to be running.Īfter all reset sources have gone inactive, a delay counter is invoked, stretching the internal reset. The I/O ports of the AVR are immediately reset to their initial state when a reset source goes active. The circuit diagram in Figure 10-1 shows the reset logic. This is also the case if the reset vector is in the application section while the interrupt vectors are in the boot section. If the program never enables an interrupt source, the interrupt vectors are not used, and regular program code can be placed at these locations. System Control and Reset Resetting the AVRĭuring reset, all I/O registers are set to their initial values, and the program starts execution from the reset vector.įor the Atmel ATmega328P, the instruction placed at the reset vector must be an RJMP – relative jump – instruction to the reset handling routine. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |