Reset vector

In computing, the reset vector is the default location a central processing unit will go to find the first instruction it will execute after a reset. The reset vector is a pointer or address, where the CPU should always begin as soon as it is able to execute instructions. The address is in a section of non-volatile memory (such as BIOS or Boot ROM) initialized to contain instructions to start the operation of the CPU, as the first step in the process of booting the system containing the CPU.

In computing, the reset vector is the default location a central processing unit will go to find the first instruction it will execute after a reset. The reset vector is a pointer or address, where the CPU should always begin as soon as it is able to execute instructions. The address is in a section of non-volatile memory (such as BIOS or Boot ROM) initialized to contain instructions to start the operation of the CPU, as the first step in the process of booting the system containing the CPU. ==Examples== Below is a list of typically used addresses by different microprocessors: ===8-bit processors=== The reset vector for 6502 processor family is a 16-bit address stored at 0xFFFC and 0xFFFD. The reset vector for 6800 and 6809 processor families is a 16-bit address stored at 0xFFFE and 0xFFFF. No Reset Vector For 8051 / 8080 / 8085 / Z80, reset starts code execution at address 0x0000. For AVR, reset starts code execution at address 0x0000; often a Relative Jump instruction (RJMP) is placed here to jump to the reset handling routine within the bottom 4K of memory. For PIC, reset starts code execution at address 0x0000. ==See also== Booting Reboot (computing) Control-Alt-Delete Power-on self-test Hardware reset ==References==

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