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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I’ll take it from there. I’ve just acquired two 74LSs and need help understanding the datasheet. If you use more than one of these ICs together with their outputs tied to the same input, you’ll need to manage the CS pins in order to ensure that both ICs don’t try to deliver data at the same time. The logic diagram on the bottom of page 4 shows why: Though having 16 buttons using that method would be pushing that technique a tad. The clock is CLK, pin 2 on the through-hole package shown at the top of page 2 in the datasheet.

That is an entirely different proposition. Eduardo Cardoso 1 The output pins are pretty obvious, and I can GUESS at the clock, data and latch pins, but would totally appreciate if someone more knowledgeable could tell me which are the clock, data and latch.


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

It sounds as though you need a proper keyboard matrix controller. You can use a couple of 74LS encoders as shown in their data sheet. The MM74C key encoder. Such an arrangement is called a “diode matrix”. You are not answering Jonk’s question.

74LS (Big) bit serial-in serial-out shift register

The most direct way to do it is to build a diode matrix: Another alternative is to turn your buttons into a rudimentary digital to analog convertor and feed that analog value into whatever analog to digital convertor you may have available. I think I like the latter best since you can grab the complete switch status at one moment datasheey time. Pressing SW2 pulls down IN1 only. Let me try this As in the picture: Load from the switches into the shift register all 16 switches attached to 16 pullups, then step feed the word back to the 74lz673.

Internal debounce with single external capacitor.

(PDF) 74LS673 Datasheet download

With all of these you would need to handle debounce in code. Add pullup resistors if necessary. Post Your Answer Discard By clicking “Post Your Dstasheet, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use 74,s673 the website is subject to these policies. You need to modify your question to clarify that you want to prevent two button pressed simultaneously giving an erroneous code.


A simple diode arrangement to encode the buttons. FYI, The most useful functions: Feed one output low through the shift register and read back the status on dattasheet common line. 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.

74LS Datasheet PDF – Texas Instruments

Perhaps a fritzing diagram and a simple sketch lighting 16 LEDs? Serial in parallel out 74LS However your statement “have to do this without one button influencing the other” and comments imply you need the ability to detect more than one button pressed at the same time. I have to do this without one button influencing the other. You even get to be able to detect SW0 thanks to the Data Available signal!

P1 through P15 are inputs for parallel-loading the shift register. Since it’s only 15 switches, another way this can be done is to use a shift register rather than an array.

I have 15 output buttons and 4 digital inputs. The Data Available will return high to indicate acceptance of the new key after a normal debounce period.