diff --git a/Electronics_and_Hardware/Digital_circuits/Clock_signals.md b/Electronics_and_Hardware/Digital_circuits/Clock_signals.md index 54320c2..5285787 100644 --- a/Electronics_and_Hardware/Digital_circuits/Clock_signals.md +++ b/Electronics_and_Hardware/Digital_circuits/Clock_signals.md @@ -10,7 +10,8 @@ tags: [binary, memory, clock, electromagnetism] In the examples of digital circuits so far (i.e [adders](/Electronics_and_Hardware/Digital_circuits/Half_adder_and_full_adder.md) and [latches](/Electronics_and_Hardware/Digital_circuits/Latches.md)) everything happens in a single instant or over several repeated instances. This is because of how simple the circuits are. In the case of latches only a single bit is updated. And even with rippled adders they are just a series of 1-bit updaters in a chain. -With more complex circuits that use multiple memory devices which store a series of bits at once, we need a way to ensure that the bits are set at theB +With more complex circuits that use multiple memory devices which store a series of bits at once, we need a way to ensure that the bits are set at the same time. We do this by sequencing the execution with the pulses of the system clock. + A single iteration of the volatage rising and falling is a **pulse**. A complete oscillation from low to high and back to low is a **cycle**. As with all [electromagnetic](/Electronics_and_Hardware/Physics_of_electricity/Electromagnetism.md) signals we measure the frequency of the wave in Hertz: cylcles per second. We also further distinguish the rising and falling edge of a pulse. Rising represents the signal passing from ground to its maximum voltage and falling is the reverse (the electrons moving from the voltage source to ground). The diagram below shows a pulse cycle of 2Hz. @@ -21,7 +22,7 @@ The diagram below shows a pulse cycle of 2Hz. - All components that need to be synchronised are connected to the clock - State changes in the component occur only when a clock pulse occurs -- | Clock-driven components will typically trigger their state changes on either the rising edge or the falling edge of the pulse. | +- Clock-driven components will typically trigger their state changes on either the rising edge or the falling edge of the pulse. - Components that trigger state changes on the rising pulse are **positive edge-triggered** - Components that trigger state changes on the falling pulse are **negative edge-triggered**