Fix BLTOUCH and FAN PWM conflicts on SKR E3 v2 boards#19205
Fix BLTOUCH and FAN PWM conflicts on SKR E3 v2 boards#19205Asterchades wants to merge 1 commit intoMarlinFirmware:2.0.xfrom Asterchades:2.0.x
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Cannot do PR's against MarlinFirmware:2.0.x has to be against bugfix. |
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| #if MB(BTT_SKR_MINI_E3_V1_0, BTT_SKR_E3_DIP, BTT_SKR_MINI_E3_V1_2, MKS_ROBIN_LITE) | ||
| #if MB(BTT_SKR_MINI_E3_V1_0, BTT_SKR_MINI_E3_V1_2, BTT_SKR_MINI_E3_V2_0, BTT_SKR_E3_DIP, MKS_ROBIN_LITE) | ||
| // SKR Mini E3 boards use PA8 as FAN_PIN, so TIMER 1 is used for Fan PWM. |
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The SKR Mini E3 V2 uses PC6 instead of PA8 as FAN_PIN, so this comment is no longer true.
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I left as much alone as I could while trying to find a solution. Someone else will need to look into that. I can't even pretend to know enough about the hardware or software to do anything else.
| #endif | ||
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| #if MB(BTT_SKR_MINI_E3_V1_0, BTT_SKR_E3_DIP, BTT_SKR_MINI_E3_V1_2, MKS_ROBIN_LITE) | ||
| #if MB(BTT_SKR_MINI_E3_V1_0, BTT_SKR_MINI_E3_V1_2, BTT_SKR_MINI_E3_V2_0, BTT_SKR_E3_DIP, MKS_ROBIN_LITE) |
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It looks like both fan pins on this board use timer 8. That means this PR should introduce a problem, rather than solve one.
More work is probably needed to identify why this seems to solve the submitter’s problem, because this looks incorrect to me.
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???
When using hardware-PWM
Using the same timer means using the same PWM-frequency - not using the the same PWM-ratio what's defined per pin.
Why shouldn't the fans share the same PWM-frequency? Do we have a way to configure different frequencies for different fans?
When using software_PWM
all fans do use the same timer anyway (that for the temperature interrupt)
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A mixed setup is currently not possible for Marlin anyway.
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This is attempting to resolve a conflict between fans and Servo output, not between the two fans. Setting fan values when they share a timer with servo output corrupts the servo output frequency.
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My bad. First ever pull request, so I'm not in the least bit surprised I got something wrong. Will close here and re-open over on bugfix. PS If you're still here, please review #19207. I don't understand how this Git system is meant to work and I'm not convinced it does either, since it's showing I'm requesting 78 commits dating back to 2019 instead of just the one. |
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Requirements
Description
Corrects the same issue as #15547 on the newer SKR Mini E3 v2 boards. Also re-ordered the conditions to put all the SKR Mini E3s together, though that has no functional benefit (though if someone knows how to wild-card the condition it could be more evident what needs to be included).
Benefits
Prevents some Z probes (notably certain BLTouch clones) from deploying randomly when the PWM fan is triggered while using a newer BTT SKR Mini E3 v2 board. Prevents damage to both the print and probe. Tested for over an hour with zero random deployments mid-print.
Configurations
N/A
Related Issues
None listed. Personal issue encountered during recent experiments which, given the previous issue, is likely to impact other users with similar configurations.