Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise . 74ls,, 74ls Matched Datasheet Manufacture, PDF . 1, 74ls, BIT SHIFT REGISTERS, Texas Instruments, 74ls pdf. Texas Instruments 74LS Logic – Shift Registers parts available at DigiKey. SN74LSDW Datasheet · SN74LSDW – Texas Instruments ·

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How do I make each button activate its corresponding address. The clock is CLK, pin 2 on the through-hole package shown datashet the top of page 2 in the datasheet.

A simple solution is to connect a diode from each input to every switch that should pull that input low.

74LS673 (Big) 16-bit serial-in serial-out shift register

74s673, I finally have a reason to use the “diagonal diode” symbol in CircuitLab. With all of these you would need to handle debounce in code.

I’ll take it from there. Datasheeet in the picture: You need to define what is to happen when 1 a second key is pressed while the first is held down 2 when the second key is released before the first and 74ld673 when the second key is released after the first. There are also purpose built chips that scan the buttons connected as an array like the 74C Or if you have the ability to program one, a small ROM or FPGA can do it.

Since it’s only 15 switches, another way this can be done is to use a shift register rather than an array. The most direct way to do it is to build a diode matrix: Available output returns to a low level when the entered key is released – even if another is depressed.



He just wants to “send a ground” to the input signals. There’s no single pin dwtasheet performs a “latch” function. Furthermore, a scanned switch matrix is easy to de-bounce. There 7l4s673 other ways that use many diodes. The logic diagram on the bottom of page 4 shows why: Post Your Answer Discard By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies.

If the voltage is negative, then reverse the direction of the diodes. FYI, The most useful functions: Home Questions Tags Users Unanswered. That is an entirely different proposition. I’ve searched the forums and it doesn’t look like anyone has asked this yet. But it’s better to show them here for completeness, remember next person searching the web and finding this question may have a different micro or idea in his head.

To change any data in the shift register at all, the clock must have a falling edge. Note that I’m assuming that the inputs rise to a positive voltage if not grounded; i. Post as a guest Name. You even get to be able to detect SW0 thanks to the Data Available signal!

I’m assuming the inputs are already pulled high by some means. How to make a button activate its corresponding binary address Ask Question. Pull-ups are required, may be internal to micro or not.

(PDF) 74LS673 Datasheet download

You need to modify your question to clarify that you want to prevent two button pressed simultaneously giving an erroneous code. The output pins are pretty obvious, and I can GUESS at the clock, data and latch pins, 74os673 would totally appreciate if someone more knowledgeable could tell me which are the clock, data and latch.


Load from the switches into the shift register all 16 switches attached to 16 pullups, then step feed the word back to the micro.

Internal debounce with single external capacitor.

74ls datasheet & applicatoin notes – Datasheet Archive

Pressing SW1 pulls down IN0 only. That looks like Trevor’s “Visio-Lab”. That’s what diodes are for. You won’t be able to use your common ground switch arrangement but all other potential problems will be solved.

Perhaps a fritzing diagram and a simple sketch lighting 16 LEDs? In that case you would need some form of keypad scanner. The Data Available will return high to indicate acceptance dztasheet the new key after a normal debounce datashet.

I have to do this without one button influencing the other. That will mean you only need three pins on the micro and a suitable algorithm to manipulate the shift register. Anyone want to make some money via online consulting?

There’s no asynchronous load function, like the load function on the 74LS Eduardo Cardoso 1 Though having 16 buttons using that method would be pushing that technique a tad.

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Add pullup resistors if necessary.