#ELECTRIC DIGITAL DESKTOP CLOCK GENERATOR#

The MOS Technology 6502 uses the same 2-phase logic internally, but also includes a two-phase clock generator on-chip, so it only needs a single phase clock input, simplifying system design. The 6501 requires an external 2-phase clock generator. Higher speed versions of both microprocessors were released by 1976. The 6800 has a minimum clock rate of 100 kHz and the 8080 has a minimum clock rate of 500 kHz. The 8080 requires more clock cycles to execute a processor instruction. The 8080 uses a 2 MHz clock but the processing throughput is similar to the 1 MHz 6800. The next generation of microprocessors incorporated the clock generation on chip. These were generated externally for both the Motorola 6800 and Intel 8080 microprocessors. Metal oxide semiconductor (MOS) ICs typically used dual clock signals (a two-phase clock) in the 1970s. Since a gated latch uses only four gates versus six gates for an edge-triggered flip-flop, a two phase clock can lead to a design with a smaller overall gate count but usually at some penalty in design difficulty and performance. Because the two phases are guaranteed non-overlapping, gated latches rather than edge-triggered flip-flops can be used to store state information so long as the inputs to latches on one phase only depend on outputs from latches on the other phase.

Traditionally one wire is called 'phase 1' or 'φ1' ( phi1), the other wire carries the 'phase 2' or 'φ2' signal. In synchronous circuits, a 'two-phase clock' refers to clock signals distributed on 2 wires, each with non-overlapping pulses. Most modern synchronous circuits use only a 'single phase clock' – in other words, all clock signals are (effectively) transmitted on 1 wire. This technique is often used to save power by effectively shutting down portions of a digital circuit when they are not in use, but comes at a cost of increased complexity in timing analysis. The only exceptions are asynchronous circuits such as asynchronous CPUs.Ī clock signal might also be gated, that is, combined with a controlling signal that enables or disables the clock signal for a certain part of a circuit. The preeminent example of such complex chips is the microprocessor, the central component of modern computers, which relies on a clock from a crystal oscillator. As ICs become more complex, the problem of supplying accurate and synchronized clocks to all the circuits becomes increasingly difficult. In some cases, more than one clock cycle is required to perform a predictable action. Most integrated circuits (ICs) of sufficient complexity use a clock signal in order to synchronize different parts of the circuit, cycling at a rate slower than the worst-case internal propagation delays.

Electric digital desktop clock