Encoder Circuit Symptoms...

DJD100

Power User
Before I R&R the Rotary Encoder (RC) I thought I'd pass my RC's symptoms past Ya'll, as I'm now thinking it might be the chip that follows it which deciphers it's output and sends it on?

a) My RC seems to always work fine in the recall page, and only has issues in various edit pages?

b) It always seems to be fine on the various ASCII edit pages, but has huge problems on various GUI edit pages?

c) Huge problems are where it won't increment or decrement the selected parameter, and if you continue to spin the RC while this failure scenario is playing out it will kind of jump between two values after you're done spinning, like it's output was buffered but not translating correctly or something? If you go real slow this will sometimes get it to increment/decrement successfully, other times not?

Anyone have any thoughts (like R&R the whole board instead of the RC etc)?

Thanks...
 
Hi DJD100, I don't have a schematic of the Axe so I can't be absolutely certain of the hardware, however I have implemented a rotary encoder on a number of commercial products (I’m an embedded software engineer) here are my initial thoughts:

The fact that the encoder “..seems to always work fine in the recall page ..” would suggest that this is not a hardware issue (otherwise it would be like that all the time) and not just in one particular mode of operation i.e. edit screen. Also a rotary encoder does not necessarily need an intermediate ‘chip’ – most can be interfaced directly to microcontroller ports, meaning that it ends up being more of a ‘low-level software exercise’ than a ‘hardware one’ to count steps.

Just a theory …
What is the processor overhead (%) for the given patch you are editing ? …i.e. I am wondering if it is getting close to 100% utilization during recall operation and then when you go into editing mode this is placing additional burden on the microprocessor causing it to ‘miss’ encoder steps’ ??? …does the encoder ‘miss steps’ on other patches you have that use less effects blocks ? Also what version of firmware are you using ?
 
Thanks a million Boolean, your expertise is much appreciated!

All good points, so I'll check the CPU usage but generally I "think" I've seen the RC issue with presets reporting roughly 85% - 93% CPU usage (metered on the Axe), though I'm not sure if the problem goes away with less CPU use. I'll test this when I get back to my Axe Tuesday evening, and report back.

Thanks again...

Hi DJD100, I don't have a schematic of the Axe so I can't be absolutely certain of the hardware, however I have implemented a rotary encoder on a number of commercial products (I’m an embedded software engineer) here are my initial thoughts:

The fact that the encoder “..seems to always work fine in the recall page ..” would suggest that this is not a hardware issue (otherwise it would be like that all the time) and not just in one particular mode of operation i.e. edit screen. Also a rotary encoder does not necessarily need an intermediate ‘chip’ – most can be interfaced directly to microcontroller ports, meaning that it ends up being more of a ‘low-level software exercise’ than a ‘hardware one’ to count steps.

Just a theory …
What is the processor overhead (%) for the given patch you are editing ? …i.e. I am wondering if it is getting close to 100% utilization during recall operation and then when you go into editing mode this is placing additional burden on the microprocessor causing it to ‘miss’ encoder steps’ ??? …does the encoder ‘miss steps’ on other patches you have that use less effects blocks ? Also what version of firmware are you using ?
 
After testing with a low CPU usage the problem eventually persisted, so I just R&R'd the Rotary Encoder, and that did it. All's good again. Thanks everyone for your help.

Thanks...

I'll test it with a lower CPU usage preset and report back...
 
I also have the sluggish encoder response changing parameter values on my Ultra. It seems to have surfaced in the last few firmware versions. The values don't move much at first, then make a big jump after a few seconds. Sorry, I don't have my AxeFX with me at the moment, so I can't test.
 
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