Search results
Results from the WOW.Com Content Network
An asynchronous (ripple) counter is a "chain" of toggle (T) flip-flops in which the least-significant flip-flop (bit 0) is clocked by an external signal (the counter input clock), and all other flip-flops are clocked by the output of the nearest, less significant flip-flop (e.g., bit 0 clocks the bit 1 flip-flop, bit 1 clocks the bit 2 flip ...
The straight ring counter has the logical structure shown here: Instead of the reset line setting up the initial one-hot pattern, the straight ring is sometimes made self-initializing by the use of a distributed feedback gate across all of the outputs except that last, so that a 1 is presented at the input when there is no 1 in any stage but the last.
A 4-bit ring counter using D-type flip flops is an example of synchronous logic. Each device is connected to the clock signal, and update together. Main article: synchronous logic
The term flip-flop has historically referred generically to both level-triggered (asynchronous, transparent, or opaque) and edge-triggered (synchronous, or clocked) circuits that store a single bit of data using gates. [1] Modern authors reserve the term flip-flop exclusively for edge-triggered storage elements and latches for level-triggered ones.
If the output of the flip-flop is low, and a high clock pulse is applied with the input being a low pulse, then there is no need for a state transition. The extra computation to sample the inputs cause an increase in setup time of the flip-flop; this is a disadvantage of this technique. [3]
A typical use of Gray code counters is building a FIFO (first-in, first-out) data buffer that has read and write ports that exist in different clock domains. The input and output counters inside such a dual-port FIFO are often stored using Gray code to prevent invalid transient states from being captured when the count crosses clock domains. [53]
ENIAC used ten-position ring counters to store digits; each digit required 36 vacuum tubes, 10 of which were the dual triodes making up the flip-flops of the ring counter. Arithmetic was performed by "counting" pulses with the ring counters and generating carry pulses if the counter "wrapped around", the idea being to electronically emulate the ...
The Signaltron main departure board at Praha-Smíchov station, Czech Republic (2012), manufactured by Pragotron Schematic of a split-flap display in a digital clock display An animation of how a split-flap display works Flap departure board at Gare du Nord, Paris (2007) Section of a split-flap display board at Frankfurt (Main) Hauptbahnhof (2005) Enlarged inner workings of a split-flap clock