ATmel AVR ATtiny84V Program Unlocking

ATmel AVR ATtiny84V Program Unlocking

There is an internal PLL that provides a 16x clock rate locked to the system clock (CK) for the use of the Peripheral Timer/Counter1 from ATmel AVR ATtiny84V Program Unlocking. The nominal frequency of this peripheral clock, PCK, is 25.6 MHz. The fast-access register file concept contains 32 x 8-bit general purpose working registers with a single-clock-cycle access time.

This means that during one single clock cycle when ATmel AVR ATtiny84V Program Unlocking, one ALU (Arithmetic Logic Unit) operation is executed. Two operands are output from the register file, the operation is executed, and the result is stored back in the register file – in one clock cycle.

Two of the 32 registers can be used as a 16-bit pointer for indirect memory access. This pointer is called the Z-pointer, and can address the register file, IO file and the Flash program memory.

The ALU supports arithmetic and logic functions between registers or between a constant and a register. Single-register operations are also executed in the ALU. Figure 2 shows the ATtiny15L AVR RISC microcontroller architecture. The AVR uses a Harvard architecture concept with separate memories and buses for program and data memories.

The program memory is accessed with a two-stage pipeline. While one instruction is being executed, the next instruction is pre-fetched from the program memory. This concept enables instructions to be executed in every clock cycle. The program memory is In-System Programmable Flash memory.

With the relative jump and relative call instructions, the whole address space is directly accessed. All AVR instructions have a single 16-bit word format, meaning that every program memory address contains a single 16-bit instruction.

During interrupts and subroutine calls, the return address program counter (PC) is stored on the stack. The stack is a 3-level-deep hardware stack dedicated for subroutines and interrupts.

The I/O memory space contains 64 addresses for CPU peripheral functions as Control Registers, Timer/Counters and other I/O functions. The memory spaces in the AVR architecture are all linear and regular memory maps when CRACK MCU.