74LSN from Fairchild Semiconductor. Find the PDF Datasheet, Specifications and Distributor Information. 74LSN Datasheet, 74LSN PDF, 74LSN Data sheet, 74LSN manual, 74LSN pdf, 74LSN, datenblatt, Electronics 74LSN, alldatasheet. These 8-bit shift registers feature gated serial inputs and an asynchronous clear. A low logic level at either input inhibits entry of the new data, and resets the first.
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Also, why does the scope only show 2Vpp in one picture?
74LSN datasheet & applicatoin notes – Datasheet Archive
The extreme top left pin from the printed side is the first pin in the order, and the pin daasheet opposite to it on the other row is the last or the 14 th pin. This opposite sequencing also takes place in accordance to the rising pulse of the input dattasheet. Looks pretty clean but you need to zoom way in to know for sure. This opposite sequencing also takes place in accordance to the rising pulse of the input clocks.
So I added a schmitt trigger between the raspberry pi and the register clock input, and now it shifts exactly the number I want. I took some photos of the scope, the first is the clock from the GPIO 74ks164n nothing and the second is the clock connected to the register.
When the asker is sourcing more than the chip can do by more than a factor of 10, I’d look there first. Hasn’t ever happened to me. I know there is a pull down and a pull up in the raspberry pi when you configure the GPIO as input, but is there a pull down when you are in output mode?
You should test with the FETs in place. You might simply have a logic level compatibility issue between Pi and the LS inputs. You might even need to replace the shift register, but probably not.
When I power-on the circuit, all the LEDs are off. Cleaning the pulse up with a 74ls146n trigger got it working, but is masking the real problem – you Pi’s GPIO line is either not being controlled correctly by your program, or it’s blown up. Through a few of my previous articles I have 74ld164n to cover the working principles of a couple of versatile ICs like the and Referring to the figure on the left we see that externally dqtasheet looks just like an ordinary pin dual in-line chip.
Now suppose if through a simple wiring pins 1 and 2 are configured in such a way that when the last pin 13 of the IC goes high while sequencing serially, it grounds the serial input 1 and 2. Thus exceeding operating conditions, all bets are off. Just disconnect the LEDs and use the scope to check outputs.
74LSN datasheet, 74LSN datasheets, manuals for 74LSN electornic semiconductor part
Post as a guest Name. Take a peek at the data sheet. The measurement or what I think is the measurement number in all the screen shots says 3. The register was clocking eatasheet times because the clock signal wasn’t enough clean.
The length of your clock wire might be a factor in this. Hopefully you will get to see another datashewt pretty soon, which will explain the practical utility of this wonderful IC. Finding out where that datashheet comes from should be the absolute first priority here. Negative seems to indicate source current, and positive sink current. I resolved my problem.
Thanks for all your advices and suggestions, have a nice day. Similarly the IC requires only an external clock signal to make its outputs swing into action and produce interesting logic sequences.
74LS164 – 8-Bit Shift Register Ser In/Para Out
I use leds to see what happen. Better yet, JamesMagnus, you have a scope. For example if the pin — outs 1 and 2 are permanently connected to the positive supply and the reset pin is joined to the last output of the IC pin 13then, as discussed earlier, once all the outputs become high the last pin 13 instantly resets the whole circuit, shutting the whole array of outputs, and the cycle repeats.
Unlike ordinary CMOS ICs which has also been discussed in many of my previous articlesthe above ICs are equipped with many different built-in features which may be accessed or activated by just applying the appropriate logic inputs or components to their relevant pin-outs. The thresholds are 0. Referring to the figure on the left we see that externally it looks just like an ordinary pin dual in-line chip.