Hello guys .
i have been trying to interface the 595 with an atmega328 with arduino bootloader and software . the results are though rather noisy and it seems to be coming from the latch pin . i have it set-up with an 1uf capacitor on the power lines . (also tried to switch that to 0.1uf for the purpose of this application and the results were the same ) . in this application two 595s are placed in series (Qh of the first is wired to Ser of the second )
after sending the signal , the chips do give out a stable output of what i need . the problem is , sometimes , a low after high signal to the Latch clock seems to allow the data to pass through .
the latch flip-flops are positive edge triggered , yet in my application sometimes the triggering happens on a negative edge . i am guessing that's because of noise , maybe the shifting to low level logic is noisy ?
so basically in an example of 10 iteration tests , it would go well 8 times (gets correctly triggered on the positive edge) , yet 2 times it incorrectly triggers on the negative edge instead .
what could be causing this problem ? thank you