5TH "Test" program on FV-1 chip solution? (will this work?)

Robert said:
No. The DPDT is wired to instantly switch to Internal then back to External when you flip the switch.

This triggers a reload of the current program from the newly selected EEPROM.
Click to expand...
So my test board finally came in, and I'm running into some issues. It seems that when I turn the rotary switch it does in fact recognize that it needs to switch EEPROMs. However 50 percent of the time it can't seem to pull any info from the chip. This again can be remedied by switching through the banks to trigger it and make it read the correct chip. However, when it does work it seems to swap EEPROMs without having to do so. I feel like I'm really close on this one!
 

Attachments

It looks like you are missing the I2C pull-up resistors on the SDA & SCL signals. This would make the I2C bus act strange and might be the issue. Add a couple resistors and see if that solves it.
 
TubeGuy said:
It looks like you are missing the I2C pull-up resistors on the SDA & SCL signals. This would make the I2C bus act strange and might be the issue. Add a couple resistors and see if that solves it.
Click to expand...
I've never used pull down resistors on the SDA/SCL of the EEPROM before. Could you explain this further please? I don't understand the purpose.
 
I think the FV-1 has internal pull-ups on the I2C lines. So you shouldn't need external ones.

Does it get any more reliable if you turn the EEPROM select switch slowly?
Try changing R29 to a 1k.
 
This may be a mechanical issue...

It could be that the reload is being triggered at the same instant that all EEPROMs are in a disabled state.

It might be necessary to add some circuitry to hold the Int/Ext pin in the Internal state for a slightly longer period. (RC filter or simple transistor switch)
 
Robert said:
This may be a mechanical issue...

It could be that the reload is being triggered at the same instant that all EEPROMs are in a disabled state.

It might be necessary to add some circuitry to hold the Int/Ext pin in the Internal state for a slightly longer period. (RC filter or simple transistor switch)
Click to expand...
This was my thought too. The reload triggers everytime. But it must be happening an instant before the EEPROMs has time to adjust to the correct chip selection.

Are you suggesting an RC filter between the switch and the funtion of R29 and Pin 13? Could you elaborate a little on this please?
 
Something as simple as this might work, but C1 might not discharge fast enough to cause a 0 state on T0...

In that case you'll want to trigger it with a transistor/RC filter delay. I'm not sure if I still have the trace but it seems like there's something along those lines in the Keeley Delay Workstation.


1708627765204.png
 
Robert said:
Something as simple as this might work, but C1 might not discharge fast enough to cause a 0 state on T0...

In that case you'll want to trigger it with a transistor/RC filter delay. I'm not sure if I still have the trace but it seems like there's something along those lines in the Keeley Delay Workstation.


View attachment 69159
Click to expand...
I'll try this first, and get back. Any recomendation on component values for C1, R1, R2?
 
You'll have to experiment with the values. R2 will need to be significantly larger than R1 so that the voltage on T0 is still high enough to be considered a logic high.

If all else fails I'll see if I still have that Workstation pedal and can take a peek at how it's done there.
 
Robert said:
You'll have to experiment with the values. R2 will need to be significantly larger than R1 so that the voltage on T0 is still high enough to be considered a logic high.

If all else fails I'll see if I still have that Workstation pedal and can take a peek at how it's done there.
Click to expand...
Killer! I reached out to Robert as well. We will see if he's willing to share some secrets. Haha

-J
 
Robert said:
You'll have to experiment with the values. R2 will need to be significantly larger than R1 so that the voltage on T0 is still high enough to be considered a logic high.

If all else fails I'll see if I still have that Workstation pedal and can take a peek at how it's done there.
Click to expand...
Tried a good number of values. Doesn't seem to be doing the trick, unfortunately.
 
Robert said:
You'll have to experiment with the values. R2 will need to be significantly larger than R1 so that the voltage on T0 is still high enough to be considered a logic high.

If all else fails I'll see if I still have that Workstation pedal and can take a peek at how it's done there.
Click to expand...
You don't happen to still have that trace, do ya?
 
Robert said:
This should work, but what you'll end up with is a PCB that can only access the internal programs and a single program from an external EEPROM.

I know, I know, that was the goal... but...

What I would recommend instead is just loading the seven internal programs onto an EEPROM along with an additional program of your choice into patch #5. Now you have access to all of the internal programs, and the ability to switch to another full set of eight just by swapping out the EEPROM.

Exact same BOM, but more flexibility.

All of the internal programs are available in SPN format on the SpinSemi website:

Spin Semiconductor - Free DSP Programs

For audio processing, Spin Semiconductor designs and markets specialized mixed signal integrated circuits for the consumer music and audio industries
www.spinsemi.com www.spinsemi.com
Click to expand...
Somewhere in here I saw a chart of which pins are high 3.3v and which are low GND for the 8 internal programs but I can’t seem to find it again.

so if 3.3v = 1 and GND = 0

I know program #0 "Chorus-reverb" is 111 and program #7 "Reverb-2" is 000. I'm looking to find the rest.
 
The program is represented as a binary number on the S0, S1, and S2 pins

S2 (Pin 18)S1 (Pin 17)S0 (Pin 16)
Program 0000
Program 1001
Program 2010
Program 3011
Program 4100
Program 5101
Program 6110
Program 7111
 
Last edited:
You must log in or register to reply here.
Back
Top