Swimming in a sea of question marks??????????????

[armdnrdy]

I'm poking around in a very unfamiliar area trying to figure out a way to switch different channels (thinking about eight) with one or two momentary foot switches. I'm not looking to achieve selective switching, (a particular channel) just up and down through the channels. I plan to switch CMOS logic signals with the 8 channels.

I'm familiar with the "standard" CMOS switching ICs 4053, 4016,4066, etc. but to my knowledge it is not possible with these ICs to switch through multiple channels with one or two hard switches.

I came across a few ICs ADG714 & ADG715 which are serially controlled octal SPST switches, but this is taking me into uncharted territory! I'm not really sure what type of signal this type of IC requires.

http://www.analog.com/static/imported-files/data_sheets/ADG714_715.pdf

Does anyone have experience with this type of arrangement!

[garcho]

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I've been interested in this too but haven't had the time to noodle yet.

[R.G.]

I'm poking around in a very unfamiliar area trying to figure out a way to switch different channels (thinking about with one or two momentary foot switches. I'm not looking to achieve selective switching, (a particular channel) just up and down through the channels. I plan to switch CMOS logic signals with the 8 channels.

To be sure I follow you, you're intending that the signals going through the switches themselves be CMOS logic levels, not audio, right?

I'm familiar with the "standard" CMOS switching ICs 4053, 4016,4066, etc. but to my knowledge it is not possible with these ICs to switch through multiple channels with on or two hard switches.

That's right. They expect to be told how to switch, and have no internal up/down counters or any such.

I came across a few ICs ADG714 & ADG715 which are serially controlled octal SPST switches, but this is taking me into uncharted territory! I'm not really sure what type of signal this type of IC requires.

It requires an external smart processor to do the serial packets into/out of them.

For your purposes, you want (I think) the 1->8 variant of the 4053 (4051, I believe) and a CMOS up/down counter. The counter provides the address for the mulitplexer, and you can then punch a momentary switch for clocking the u/d counter.

[R.G.]

CD40193 has separate count-up and count-down clocks. You may have to precondition these with a Schmitt trigger gate like the CD40106, CD4584, or 74C14 in front of it, which would be handy anyway because that would let you use a footswitch connection to ground.

[armdnrdy]

R.G. Thanks for the direction. I'll do some research along that path.

I was looking at another multiplexing switch IC (AGD407) which showed a truth table in the data sheet.
That was something a bit more familiar as I have just finished building a frequency counter with two, three digit multiplexed LED displays.

The counter design switches between 1Htz-1mHz (displayed in hertz) and 1Htz-10mHz (displayed in Kilohertz) When I was finished with the build, I noticed that when in the 10mHz (kilohertz) mode the last two digits are actually 10ths and hundredths! It needed a decimal point for the readout to be correct.

Well after much research I found a way to light the decimal point when the rotary switch was in the 10mHz position. Since the LED displays are multiplexed common cathode, it took a lot more than applying power to the anode of the decimal point to light it!

Since I didn't have a 4023 handy, I "made" a 3 input nand gate from a 4011. I had to make a small daughter board so that one particular decimal point would "see" the logic and light.

So basically, I do understand a micro amount about multiplexing  I'm sure after diving in to this switching arrangement, I'll have a better understanding.