Clock circuit of 8051 Microcontroller Family
Clock circuit of 8051 The 8051 has on chip oscillator pin XTAL1 and XTAL2 are provided for connecting a resonant network to from an oscillator crystal frequency ranges from 1 MHZ to 24 MHZ. Ceramic resonators may be used as a low-cost alternative to crystal resonators but due to decrease in frequency stability and accuracy, ceramic resonators are not preferred for high-speed serial data communication with other system. The oscillator formed by the crystal, capacitors, and on chip inverter generates pulse train at the frequency of the crystal as shown in fig. The clock frequency & establishes the smallest interval of time within the microcontroller, called the pulse, p, time. The smallest interval of time to accomplish any simple instruction, or part of a complex instruction, however, is the machine cycle. The machine cycle is made up of six states. A state is the basic time interval for discrete operations of the microcontroller such as fetching on encode byte decodin