switch that uses silicon gate CMOS technology to. – One Assembly and Test Site, One Fabrication achieve operating speeds similar to LSTTL, with the. Site. 18 Aug The SparkFun Multiplexer Breakout provides access to all pins and features of the 74HC, an 8-channel analog multiplexer/demultiplexer. 19 Dec The 74HC; 74HCT is an 8-channel analog The VCC to GND ranges are V to V for 74HC and V to V for.
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The biggest noise issue I had was with an XBee on the 3. But since it’s connected between vcc and ground, does it matter where in the circuit it’s positioned? For example on row here: I just know what have worked for me.
Potentiometers affecting each others when connected to 74HC I’m trying to implement a small scale version of this circuit https: I’ve updated the page to also recommend 74hc40511 parts. I 74hc401 out I got best results with a microsecons delay and an averaging of Tried to increase delay and it behaves more reliably now, I guess I should have included an image in the first place.
Even if the on resistance is about 4X that’d be my 74hx4051, based 74uc4051 my understanding of the transistors that are probably inside the chipthe pot is still the limiting factor. I need to know because I’m planning on using 1 74HC to run 6 buttons off one pin of the teensy’s digital pin and 7 more running on the analog pins.
Are there any drawbacks when using the 3. Could larger pot values help?
For my projects, I’ve needed at most so I have read at higher resolution and discarded the “change” if it’s been less than a low resolution value step. I have teensy 2. Originally Posted by loveaurell. That’s contrary to the normal nonHC advice, where adding capacitance tends to improve analog measurement quality.
74HC – Arduino, NodeMCU, Digispark and ESP
I’d done quite a bit of testing with different capacitors on Teensy 3. Your code above has only 0. Ah, when I wrote above, there was no picture, so I was not aware of the capacitor. When you change the 74HC control signals, the resistance of the pot plus resistance of the switch inside the 74HC begin slowly charging or discharging the capacitor.
Page 1 of 2 1 2 Last Jump to page: The time now is I did find one pot to be noisy and replaced it. They also will consume 3. If It turns out that the 74HC is not the right tool for this, is there another way to expand the number of inputs of the teensy?
Paul is right, that introduces an additional “time constant”. But I think the code should work.
I’ll also try the digital low pass filtering to see if that helps, Theremingenieur. All times are GMT. The simplest 74hc0451 is to minimize the capacitance. Opps, make that delay closer to 4ms. I’ll play around with the values ans see if I can lower the delay.
I sample four times and average for each pot. Originally Posted by PaulStoffregen. Added question 74hd4051 delay times. The worst case resistance is half the pot value, plus whatever the 74HC happens to be. You might also need to experiment with analog read averaging. So 7hc4051 a 1 us delay ought to be enough. What values would be ideal for steady values at low delay? It does, but only if the capacitor has stabilized to the right voltage before you make the measurement.
Most plastic film “poly” capacitors also work well.
Is 10k a suitable potentiometer value? Now, when I receive midi messages I notice that some random pots change readings. If so, you’re going to need to allow at least 3 ms from the time you change the 74HC control pins to when you call analogRead.
I’d recommend using only pF capacitance, or no capacitor at the A0 74h4051 at all. Thank you very much for the great explanation!