Part Number: SN74HC74-Q1
I have encountered a problem with the application of the D flip-flop, the model used is SN74HC74-Q1. They are the schematic diagram and the waveform captured by the oscilloscope
CH1 (yellow) is the power-on waveform of the CLR pin, and CH2 (green) is the trigger output waveform.When the oscilloscope scan is placed on the CLK pin, the conversion output remains predetermined.Please help analyze whether it is improper use or the material itself may be defective.
scope waveform attached
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In reply to Pei Gong:
Is the MCU actively driving the D and CLK pins?
Can you show those waveforms as well (D, CLK, CLR\ , Q - together in 1 scope shot?)
If you only have a 2 channel scope, you can take 2 at a time, always keeping 1 the same so I can compare timing.
Also - I would highly recommend against connecting an RC like this directly to the CLR\ pin. This causes excessive current at every startup event, and can effect reliabilty. If you switch to using the SN74HCS74-Q1, then you can do this without any ill effects.
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