9/14/2023 0 Comments Cd74hc4067 arduino![]() ![]() The board also breaks out the chip’s “enable” pin, which when driven high, will completely disconnect the common pin (all switches “off”). ![]() The internal switches are bidirectional, support voltages between ground and VCC, have low “on” resistance and low “off” leakage, and to prevent crosstalk, perform “break-before-make” switching. By using multiple boards, you can create similar arrangements for I2C, SPI, etc. If you want two-way communications, you can add a second board to route your microcontroller’s TX line to 16 device’s RX lines. You can then select any one of those 16 devices to listen to. For example, you could use it to connect the TX pins of 16 devices to one RX pin on your microcontroller. Since the mux/demux also works with digital signals, you can use it to pipe TTL-level serial data to or from multiple devices. This allows you to connect up to 16 sensors to your system using only 5 pins! To control it, connect 4 digital outputs to the chip’s address select pins (S0-S3), and send it the binary address of the channel you want (see the datasheet for details). It works with both digital and analog signals (the voltage can’t be higher than VCC), and the connections function in either direction. This chip is like a rotary switch - it internally routes the common pin (COM in the schematic, SIG on the board) to one of 16 channel pins (CHANxx). Serial.println("keypad interfacing_CD74HC4067 starting.This is a breakout board for the very handy 16-Channel Analog/Digital Multiplexer/Demultiplexer CD74HC4067. Here is the final code: // interfacing mux with tp223 Secondly, in the code, I had an elementary failure to initialize the A0 analog pin as: CD74HC4067 16-Channel Analog Digital Multiplexer Breakout Board Module for Arduino - RS1164 Chipset: CD74HC4067 Channels: 16 Address Lines: 4 Supply: 2V to. In this way I stopped having those random volt measurements. Firstly, I pulled down the Signal with a 10K resistor. There was a cabling and a software issue as well. I finally managed to get a solution to my problem. I measure volts between signal and ground at the capacitive touch pad, when touched i get 3.9v When i touch the pad (connected to c0) i get: press any key to continue. When nothing is touched/pressed, i get the following: press any key to continue. I got hold of a new CD74HC4067 and connected just one capacitive touch pad. Unless there is another suggestion I will look for a couple of these (CD74HC4067) as soon as possible. The problem is that I can't test another CD74HC4067 since i have only one right now. ![]() I think that there must be some kind of short circuit somewhere but it is not visible. But the strange thing is that when i touch the ttp's I measure 2.xx Volts at all the mux channels. When ttp's are touched TTP_SIGNAL to GND i measure a 3.94-3.88v. When the system is resting I measure 4.93V at the ttp's Vs to GND and 0V TTP_SIGNAL to GND. Is there a need for a pullup or pulldown resistors in this setup? Should I connect a resistor to each S0-S3 with ground? Why is this not working? Īnd I get no HIGH on channel 12 as I should. Īnd then after each sample run all channels seem to get lower values. On my first run after a boot: press any key to continue. With ttp123 touched, I would expect to get a high on SIG when I write, to S0-S3. Just for simplicity, I have connected only one ttp123 on the system, ttp123 signal to channel12 on 74HC4067. ![]() ") Ī= Serial.readString() // read the incoming data as stringĭigitalWrite(controlPin, muxChannel) Serial.println(" press any key to continue. Serial.println("keypad interfacing_CD74HC4067 starting.") Here is my code: //Using CD74HC4067 16-Channel Analog Multiplexer I expect when a ttp123 is pressed to trigger a HIGH and this event to be passed to SIG pin. I power the setup with a separate 5v and the arduino is connected on a pc usb port. The S0-S3 pins are connected to digital Pins D6 to D9 on a pro mini. Each ttp123 signal is connected to one of the 0-15 pins of the CD74HC4067. More specifically i am trying to build a keypad with multiple ttp123 break-boards. I am working on a project that needs multiple digital signals and I am considering the CD74HC4067 (on a break-board) to work as a multiplexer. ![]()
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