06-16-2021, 09:24 AM
Bit of a sad update, as it turns out the "secondary function" PWM pins on the Pi bus are not actually usable. They are assigned to vital rk805 functions, so the I2C which they are used for by default cannot be disabled.
On the plus side, I did finish the level shifting circuit:
![[Image: 5vfan.png]](https://overviewer.org/~pillow/up/c534e98b01/5vfan.png)
Theoretically, I can use this on any future SBC which does actually expose PWMs in a way (hello Quartz64 Model A) or on an SBC where a simple hack can be made to get a PWM (hello ROCKPro64 IR header)
For now though, I'm a bit bummed out. I can power the fan fine at full speed with just USB or the 5V and GND lines, so this still has a use of course. I might revisit this on a different SBC.
On the plus side, I did finish the level shifting circuit:
Theoretically, I can use this on any future SBC which does actually expose PWMs in a way (hello Quartz64 Model A) or on an SBC where a simple hack can be made to get a PWM (hello ROCKPro64 IR header)
For now though, I'm a bit bummed out. I can power the fan fine at full speed with just USB or the 5V and GND lines, so this still has a use of course. I might revisit this on a different SBC.
Occasional Linux Kernel Contributor, Avid Wiki Updater, Ask Me About Quartz64
Open Hardware Quartz64 Model A TOSLink Adapter
Pi-bus GPIO Extender For ROCKPro64 And Quartz64 Model A
Plebian GNU/Linux
