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Octal D Latch

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I was looking around for some schematics for a pic programmer and i found an extremely simple one (simple is good :p)
but there was another IC in the circuit and it was a HCT something or other ... and i managed to find out it was an "Octal D Latch"
could anybody please explain what one of these actually does? ive looked for articles on it but found nothing!



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Probably a 74HCT373 or 573? A latch is a digital storage element. While the latch enable (LE) is high on these parts, the outputs (Q) will follow the state of the inputs (D). The latches are said to be transparent in this mode. On the falling edge of LE, the state of the inputs is "latched" and the ouputs retain this state until LE goes high again.

A latch differs from a D-type flip-flop (or register) in that the flip-flop doesn't have a "follow" mode. A flip-flop's output only changes on a clock transition (there are both negative and positive edge-triggered flip-flops, just as some latches latch on the rising clock edge.).
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