FV-1 Program Selector

[free electron]

Here is something that might be useful while playing with the SpinSemi FV-1 chip:



MOS 4532 8bit priority encoder is used to convert the 1P8T switch positions directly into the binary code.
Apart from the switch, it's only 4 parts, no programmer needed. S2,S1,S0 outputs are connected directly to the FV's address lines.
The switch is made by CTR, part number: RS1611-18-FB15B7.0-00-G78:
http://www.tme.eu/en/details/rs1611-18/rotary-switches/ctr/rs1611-18-fb15b70-00-g78/#
http://www.musikding.de/Print-rotary-switch-1P8T





The gerber files for the PCB are here:
https://github.com/hexeguitar/FV1_ProgSelector



Enjoy!
Piotr

[slacker]

Very nice, I like the use of those resistor packages, thanks for sharing. Quick question, what are the two things with the double arrows bottom left on the schematic, the mounting holes?

[Ice-9]

Very nice, I like the use of those resistor packages, thanks for sharing. Quick question, what are the two things with the double arrows bottom left on the schematic, the mounting holes?

Just a guess but those symbols I think are the two mounting pins/tags from the 1p8t switch,

great work free electron, nice neat little pcb

[free electron]

Mick is right. These two symbols are the mounting pins of the 1P8T switch.
These pins are not grounded by default, but i have provided a small jumper pads, a blob of solder or a 0603 jumper will ground the body of the switch.

Thanks!

[Ice-9]

Nice touch on providing whether or not to use a ground option for the switch case.

[amz-fx]

I have used the CD4532 as an encoder for use with the FV-1.

Here is an idea that I had, as yet untested, to make a footswitch that can toggle between two patches.

Disconnect the common of the 1P8T switch from 3v3. Add an SPST footswitch and connect one lug of the switch to the common of the 1P8T, and the other lug of the footswitch to 3v3.  The footswitch connects/disconnects the 3.3 volts from the common of the selector switch.

What does this do?   With the footswitch closed, the circuit behaves just as before and the 1P8T will select the address to be sent to the 3 output pins.

When the footswitch is toggled so that it is open, the select pins are all pulled to ground and the address lines go to 000.

So, you have 2 patches that can be selected by the footswitch...  Patch #1 (000) and the Patch 1-8 (000 to 111) that can be selected by the 1P8T.  Obviously when the selector switch is on position 1, there will be no difference between the footswitch selections (almost).

What is different in patch #1 with the footswitch open or closed?  Pins Gs and Eo are different in those states and will toggle off/on, so they can be used as patch bank indicators to drive LEDs.  Pin G2 is on when the 1P8T selector switch is active and off when the footswitch is open. Pin Eo does the opposite: off when the 1P8T selector switch is active and on when the footswitch is open.

Let's say that you have the 1P8T selecting patch #8 with the footswitch closed, i.e. providing 3v3 to the common of the 1P8T. The address lines Q0, Q1 and Q2 will be 111.  Gs=1 and Eo=0. When you hit the footswitch, the common of the 1P8T is floating so all of the selection lines are pulled to ground and the address lines Q0, Q1 and Q2 will be 000. Gs=0 and Eo=1. You have jumped from Patch #8 to Patch #1 merely by stepping on the footswitch.  If you are driving indicator LEDs with Gs and Eo then they will toggle to indicate the option of default or switch-selected address. Any of the patches 2 through 8 can be selected by the rotary switch for this purpose...  actually patch 1 can be selected to but that doesn't do anything except cause Gs and Eo to switch states.

As I said previously, I have not tested this yet but it should work.

Enjoy!

regards, Jack

[free electron]

Cool idea Jack! I have simulated it and it works.
Here is the schematic with your suggestions:



Of course all that and much more could be done with a small MCU, but let's put them aside for awhile ands share some old school ideas.
Here is a part of my very old project (Dip switch programmable 8 channel FX bypass looper)



It uses a momentary switches to set the address, which is then latched by the LS75. The '138 was used to drive the LEDs and show the active channel. Alternatively, a '47 could be used to drive a 7 segment display.
The Q0,Q1,Q2 outputs of the 74LS75 quad latch could be used to address the FV1.

[Digital Larry]

I've thought about using jumper blocks or DIP switches internally to a pedal to allow selection via footswitch between any 2 of the 8 FV-1 programs.  You could even go internal/external but by and large I ignore the internal programs.  In such a case you could just use the 3 bits and forget about the encoder.

[free electron]

Another option: there are 16 position / 4bit binary coded rotary switches made by LORLIN. With a small discrete inverter they could be used to flip one EEPROM address line to get 16 available programs.
Here's the idea:

[Ice-9]

A simple footswitch with patch number, momentary footswitch scrolls through 1-8. It is PIC based. I made this a couple of years ago just for fun.

Copper side picture doesn't have the pic soldered in place.





Lots of room for improvement.

[free electron]

Sure, with a micro you can do a lots of stuff. Does it save the last used program, so next time you power it up it will be the same?

I built my own FV-1 dev board few years ago, also PIC based (18F2550). It has a few nice features:
- built in USB EEPROM burner,
- one internal EEPROM and a port to attach another one externally (using that as generic eeprom programmer now)
- three DSP clocks: 16kHz, 32kHz and 48kHz
- dsp program switching is done with a pot + 7 segment led display

[Digital Larry]

I'm impressed.  One of the drawbacks of just switching between two patches is that rarely are the pot positions ideally in the same place for both of them.  So it's probably best to use a micro so that the pot positions can be stored also.