A counter is a logic circuit that implements counting operations. In a digital system, a counter mainly counts the number of pulses to achieve the functions of measurement, counting and control. It also has a frequency division function. The counter is composed of It consists of a basic counting unit and some control gates. The counting unit is composed of a series of various types of flip-flops with the function of storing information.
#The operating environment of this article: Windows 7 system, Dell G3 computer.
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Counting is the simplest and most basic operation. The counter is a logic circuit that implements this operation. In a digital system, the counter mainly counts the number of pulses to achieve the functions of measurement, counting and control. It also has a frequency division function. The counter is composed of a basic counting unit and It is composed of some control gates, and the counting unit is composed of a series of various types of flip-flops with the function of storing information. These flip-flops include RS flip-flops, T flip-flops, D flip-flops, JK flip-flops, etc.
Counters are widely used in digital systems, such as counting instruction addresses in the controller of electronic computers in order to sequentially fetch the next instruction, and recording additions and subtractions when performing multiplication and division operations in the arithmetic unit. times, such as counting pulses in digital instruments, etc. The counter can be used to display the working status of the product. Generally speaking, it is mainly used to indicate how many pieces of folding and plating work the product has completed. Its main indicator is the number of digits in the counter, the common ones are 3 digits and 4 digits. Obviously, the 3-digit counter can display up to 999, and the 4-digit counter can display up to 9999.
Function
The most commonly used sequential logic circuit in digital electronic technology. Counters can not only be used to count clock pulses, but can also be used for frequency division, timing, generating beat pulses and pulse sequences, and performing digital operations. However, the calculation results cannot be displayed. Generally, they must be displayed through an external LCD or LED screen.
Type
1. If classified according to whether the triggers in the counter flip at the same time, the counter can be divided into two types: synchronous counter and asynchronous counter.
2. If classified according to the increase and decrease of numbers during the counting process, counters can be divided into addition counters, subtraction counters and reversible counters. Those that continue to increase with the clock signal are addition counters, and those that continue to decrease are subtraction counters. Counters that can be increased or decreased are called reversible counters.
There are also many categories that are not listed one by one, but the most commonly used category is the first category, because this category allows people to know at a glance what triggering method the counter is, so that the designer can easily Circuit design.
In addition, counters are often divided into binary counters, decimal counters, etc. according to the counting system of the counter.
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