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Topic: 74HC574N, what's it good for? (Read 2697 times) previous topic - next topic

Zedkon

I recently went for some component shopping and on my list I had some shift registers. Mind you, I'm new to integrated circuits and when NONE of the shops I visited had the 74HC595 I decided to just buy something with a similar name, hoping that it would work in a similar way. But the data sheets go on and on about it being an "Octal D-type flip-flop; positive edge-trigger; 3-state" and it working as a "Bus interface". Can I use this IC for any LED based projects? Or any beginner's projects for that matter?

Grumpy_Mike

Yes, connect it's data up to 8 output pins. Then connect another output pin to the clock.
You can then latch 8 LEDs from 9 pins.

However if you add another latch to the same output pins and clock it with a different pin you then get 16 LEDs from 10 pins.
For each additional latch you get 8 more LEDs for only one more output pin.
Any use to you?

mixania

Shift Registers are cool when you want to free some pins on your Arduino.

MarkT

the 574 (in fact the '174, '274, '374 and possibly the '474 too) are clocked D-latches.  The typical use
for such a chip is in a microprocessor system to gate the system databus into an I/O device only when the
specific I/O address is decoded.

An address decoder is used to drive the clock (common to all the latches), the data bus is then copied to the output
of the latch only when the correct I/O address is present - you have written a value to the device!

For latches with tristate outputs they can be used to read from an I/O device - the OE (output enable)
pin is driven from the address decoder - however latching is not necessary for this, a '244 or '245 can
used (tri-state buffer).

Basically these chips are designed for parallel I/O, not serial I/O like the '595
[ I DO NOT respond to personal messages, I WILL delete them unread, use the forum please ]

Zedkon

Wow, quite fascinating, I'm sure these ICs will come in handy someday, if not, then I'll be sure to find a use for them at some point. Thanks for all the advice guys!

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