Timing and Control Unit : This is a control section of 8085 made up of synchronous sequential logic circuit. It controls all internal and external circuits in the microprocessor system. It operates with reference to clock signal. It accepts information from instruction decoder and generates micro steps to perform it. In addition to this, the block accepts clock inputs, performs sequencing and synchronising operations. The synchronization is required for communication between microprocessor and peripheral devices.
The contents of the instruction register are in the form of 0's and 1's. They are converted to meaningful form by the decoding network called matrices. The control matrix provieds internal signals for controlling operation and data between registers. The control unit also generate timing signals essential for microprocessor to operate. The microprocessor uses a quartz crystal (LC or RC circuit) to determine the clock frequency, so that other timing and control signals are developed. The speed of microprocessor is directly proportional to the speed of the crystal. The clock speed and access time must be compatible for maximum performance. To implement