Even-number-of-times Gray code counter circuit

Abstract

The invention relates to an even-number-of-times Gray code counter circuit, which belongs to the field of integrated circuits. The even-number-of-times Gray code counter circuit in the invention can count for 2N times; the output is an M-bit Gray code, wherein M and N are both positive integers, and the specific value of M is determined by the formula; the Gray code counter proposed by the invention comprises M+1 groups of triggers and a control module; it is determined that in the M+1th group to the second group of triggers, the M-bit Gray code is output by taking the Q output end or QB output end of the M+1th D trigger to the second D trigger as the output end of the M+1th group to the second group of triggers according to the Nth time of counting; the control module comprises an AND gate; the input end of the AND gate is connected with the M-bit Gray code; the output end thereof outputs a flag signal FLAG; when counting to the Nth time, the flag signal FLAG is logic 1 and logic 0 for the rest; and the M+1 groups of triggers are respectively composed of one D trigger and respective logic circuit. According to the even-number-of-times Gray code counter circuit in the invention, atransition state does not appear between the adjacent counting code values; the circuit is simple; and counting of any even number of times is realized.

Description

technical field [0001] The invention belongs to the field of integrated circuits, and in particular relates to a gray code counter, which can realize even counting. Background technique [0002] With the development of electronic technology, the clock frequency and data transmission speed in many fields have reached GHz, such as PIC interface, SATA interface, etc. The stability and uniqueness of traditional binary counters are difficult to guarantee. For example, when the digital signal 0011 1111 (63) of the eight-digit counting system changes to 0100 0000 (64), although the signal only increases by one unit in terms of value, the system 7-bit level flip is required internally to complete this change. Thus, 00111101 (61), 00101001 (41), 00101000 (40), 01101000 (104), 01100000 (96) and other error transition states may appear, these transition states will increase the uncertainty of the counting results, if the counting system uses In the work of chip selection or address s...

AI Technical Summary

Problems solved by technology

[0015] Among the above two methods, the first one is to convert the binary counter code word into Gray code, because the binary counter has a transition state, so the converted Gray code also has a corresponding transition state, so the stability of the output Gray code cannot be guaranteed. sex and uniqueness

The second type of Gray code counter can obtain the digital value of Gray code without transition state, but only for N-bit Gray code, that is, 2 N Counting, cannot count any even numbers, has limitations in use

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