multi position switch (digital dip switch)

[ericgibbs]

hi bdm,
Did you read my post #18.???

 

[baxterdmutt]

hi,
Does the existing 6 bit DIP switch pull the 6 lines to 0V or to a high voltage.??
Measure with a DVM the voltage on the DIP switch pins, with a switch closed and open, lets know....

Hi,
It appears to be pulling to 0V. Although at times I get 0.1 but I guess that is 0 for our purposes. Was I correct about Q1 being the 33 count.

 

[ericgibbs]

Hi,
It appears to be pulling to 0V. Although at times I get 0.1 but I guess that is 0 for our purposes. Was I correct about Q1 being the 33 count.

hi,
In order to choose the correct logic voltage, as well as the 0V for an active switch, we need to know whats the voltage on the switch when its not used.?

Counting from '0' its the 32th Count as a RESET

 

[baxterdmutt]

hi bdm,
Did you read my post #18.???

Yes, See #22.

 

[baxterdmutt]

hi,
In order to choose the correct logic voltage, as well as the 0V for an active switch, we need to know whats the voltage on the switch when its not used.?

Counting from '0' its the 32th Count as a RESET

It look to me like there is 0.2V when open.
I will use 32 so I need 33 count to reset and I think that works out to Q1.

 

[ericgibbs]

It look to me like there is 0.2V when open.
I will use 32 so I need 33 count to reset and I think that works out to Q1.

hi.
'0' to '31' is 32.... the on the 32th reset to '0' again.

From the switch voltage it appears the switch driver logic needs to tristate or o/c output logic.

 

[baxterdmutt]

OK, I think I got the voltage. There is 0.1 between each of the 5 terminals and the common. There is 7 volts between the common and the radio ground. Just so you can see where the dip switch is used this is a schematic of the ctcss package I am using: https://www.repeater-builder.com/com-spec/pdfs/com-spec-ss-32smp.pdf

 

[baxterdmutt]

OK, I think I got the voltage. There is 0.1 between each of the 5 terminals and the common. Just so you can see where the dip switch is used this is a schematic of the ctcss package I am using: https://www.repeater-builder.com/com-spec/pdfs/com-spec-ss-32smp.pdf

My last post might have been confusing. So I will clarify. The ground bus (shown in the schematic) is negligible voltage 0.01 to 0.2 (seems to vary) across each of the 5 dip terminals relative to the ground bus during transmit.

I was just going to run the counter outputs to the 5 terminal but I am wondering if that would work now or if I need some sort of interface between the counter outputs and the 5 dip terminals. But since it just needs to each of the 5 pads (as required) to ground I think I need to do something there. What do you suggest?

By the way thanks for everything this far, it has been very helpful.

Roger

 

[baxterdmutt]

hi.
'0' to '31' is 32.... the on the 32th reset to '0' again.

From the switch voltage it appears the switch driver logic needs to tristate or o/c output logic.

AAAH!, that is what I meant and confused myself, sorry. So If I am not mistaken the reset would take place on the Q1 of the second IC or did I get that wrong.

 

[ericgibbs]

AAAH!, that is what I meant and confused myself, sorry. So If I am not mistaken the reset would take place on the Q1 of the second IC or did I get that wrong.

hi Roger,
A clip from the pdf, please confirm this is the device in question.
When you measure voltages on the IC, use the bottom end of the 5.1Vz as the meters 0V connection.
Re-measure the voltages on IC100 switch pins, using the 0V as stated, I would expect them to be about +5V when not switched to 0V

I would recommend that when you connect the extra logic, you use the the 0V mentioned, as the ONLY 0V connection point.
It would be advisable to have a 5Vregulator connected to the +V terminal [top end of the 470R]. a 78L05 regulator would be OK.

Let me know what you measure...

 

[ericgibbs]

hi,
I guess by now you are realising how 'big' this switching circuit is going to be.

The fact that you want to display in decimal, on LED's, a 5 bit binary number means the BCD to Binary conversion requires discrete logic as does the inversion of the 'true' Binary values to their compliment state.

Is there anyone who could program a small PIC for you.???

 

[baxterdmutt]

My meter may not be measuring correctly. I get -0.00 to -0.1 when I measure between those points. If I measure from the radios ground to the encoders dip ground I get 7 volts. Does that make any sense.

 

[baxterdmutt]

hi,
I guess by now you are realising how 'big' this switching circuit is going to be.

The fact that you want to display in decimal, on LED's, a 5 bit binary number means the BCD to Binary conversion requires discrete logic as does the inversion of the 'true' Binary values to their compliment state.

Is there anyone who could program a small PIC for you.???

I guess I could program a pic. I started this so I would like to see where it ends up.

 

[MikeMl]

When measuring the encoder in the radio, the two things that matter are the (open-circuit) voltage across an open DIP switch, and how much current flows through your DMM when it is set up to read current and the probes are connected across an open DIP switch.

 

[baxterdmutt]

When measuring the encoder in the radio, the two things that matter are the (open-circuit) voltage across an open DIP switch, and how much current flows through your DMM when it is set up to read current and the probes are connected across an open DIP switch.

Well as I said. The voltage I get where you indicated in the diagram is 0.1 I tried checking for current and I get 0. Again if I check the dip common to radio ground I get 6Ma and 7volts. I am wondering if I am not showing anything because of RF. The encoder only comes on in transmit.

 

[baxterdmutt]

I checked, there is no rf going through it. Sorry, I cannot get any real reading across those points so let's assume that it is 7 volts where would I go from there. I only need to close the circuit with something that will handle 0 to 7 volts. What would I use for that.

 

[ericgibbs]

Well as I said. The voltage I get where you indicated in the diagram is 0.1 I tried checking for current and I get 0. Again if I check the dip common to radio ground I get 6Ma and 7volts. I am wondering if I am not showing anything because of RF. The encoder only comes on in transmit.

If you use open collector output logic IC's and set the IC output to a LOW to select a pin, dont apply any external voltage from these IC's.
Its all explained in the IC100 datasheet.

 

[baxterdmutt]

If you use open collector output logic IC's and set the IC output to a LOW to select a pin, dont apply any external voltage from these IC's.
Its all explained in the IC100 datasheet.

Well you stumped me again. I did a search for IC100 and can't seem to find it. Would that be like a 7407?

 

[baxterdmutt]

Sorry to sound a bit dense at times, but as I said earlier, I have never put together anything that involved logic but thought that doing something like this that is not too involved would help me learn.

 

[ericgibbs]

Well you stumped me again. I did a search for IC100 and can't seem to find it.

Its included in the link you posted in post #27.
It explains in the text and shown in the select switch diagrams how to connect them.
You can see it states that to select a pin , connect it to 0V.
When the IC100 is operating you should be able to measure +5V on its power pins.

I suspect the actual IC100 is a customised IC for the Comms Specialist Co.