Zologrel 74LS Big bit serial-in serial-out shift register You forgot the pull-ups though. A simple solution is to connect a diode from each input to every switch that should pull that input low. Sign up using Email and Password. Home Questions Tags Users Unanswered.
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Zologrel 74LS Big bit serial-in serial-out shift register You forgot the pull-ups though. A simple solution is to connect a diode from each input to every switch that should pull that input low. Sign up using Email and Password. Home Questions Tags Users Unanswered. Email Required, but never shown. To change any data in the shift register at all, the clock must have a falling edge. This two-key roll-over 47ls provided between any two switches. That is an entirely different proposition.
Yes, my inputs are already pull-up, the problem is that dtasheet this type of configuration I can only recognize one key at a time, if I activate keys 1 and 2 at the same time the input will receive 3. P1 through P15 are inputs for parallel-loading the shift register. A simple diode arrangement to encode the datsheet. Sign up using Facebook. You can use a couple of 74LS encoders as shown in their data sheet.
Do I gather that you also want to be able to somehow recognize N-key press events? 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.
The Data 74le will return high to indicate acceptance of the new key after a normal debounce period. The most direct way to do it is to build a diode matrix: How to make a button activate its corresponding binary address Ask Question.
74LS673 DATASHEET PDF
Perhaps a fritzing diagram and a simple sketch lighting 16 LEDs? The Data Available will return high to indicate acceptance of the new key after a normal debounce period. Though having 16 buttons using that method would be pushing that technique a tad. Anyone want to make some money via online consulting? You even get to be able to detect SW0 thanks to the Data Available signal! You need to modify your question to clarify that you want to prevent two button pressed simultaneously giving an erroneous code.