MICROPROCESSOR AND MICROCONTROLLER

Detailed explanation-1: -Each machine cycle in the 8051 is 12 clock cycles, giving an effective cycle rate at 1 MHz (for a 12 MHz clock) to 3.33 MHz (for the maximum 40 MHz clock). The oscillator circuit generates the clock pulses so that all internal operations are synchronized. One machine cycle has 6 states. One state is 2 T-states.

Detailed explanation-2: -In 8051-based system, the crystal oscillator has a frequency of 11.0592 MHz when C/T bit of TMOD is 0. Each machine cycle is made up of 12 clock cycles. Hence for a single machine cycle, the frequency becomes 1/12 × 11.0529 MHz = 921.6 KHz.

Detailed explanation-3: -Generally for most processors, it takes twelve clock cycles for one machine cycle to complete . And one instruction cycle might take one or maximum four machine cycles to execute the one instruction.

Detailed explanation-4: -The crystal frequency of 8051 is 12 MHz . Therefore the machine cycle for a system of 12MHz is µ 1 µ s .