aaannndddyyy wrote:have just ordered a 24 Mhz 3 PIN CERAMIC RESONATOR off Ebay item no 270185419501 and will try that when it arrives.
Bro you are awesome! I have been looking for these! Overclock here I come!
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... %26fvi%3D1
So right now people who have this controller can modify it to work at higher critical frequency!
This fixes the problem with many geared motors.
The controller currently uses a 20-mhz MCU but only a 16-mhz resonator.
The resonator controls the clock speed of the MCU (just like in a PC CPU).
When combined with the MCU program code, the 16-mhz resonator produces a controller critical frequency of 325-hz.
The 16-mhz resonator is too slow. It is the main cause of the problem (other than sloppy code).
If a new resonator is 20-mhz, (0% MCU overclock) then the new critical frequency = 325-hz*20/16 = 406-hz.
This will solve the Bafang PMGR problem at 72V nominal.
If a new resonator is 24-mhz, (20% MCU overclock) then the new critical frequency = 325-hz*24/16 = 488-hz.
This will solve the PUMA PMGR problem at 36V nominal.
If a new resonator is 44-mhz, (120% MCU overclock) then the new critical frequency = 325-hz*44/16 = 894-hz.
This will solve the PUMA PMGR problem at 72V nominal. It may also kill the MCU or not "spark it up" at all. Oh well.
Maybe Keywin would please ask his pcb vendor to make some new boards with 40-mhz MCU and 44-mhz resonator or crystal oscillator?
There should be no additional cost to make it better and the code can stay exactly the same.
If a new resonator/oscilator is 44-mhz, and a new MCU is 40-mhz (10% MCU overclock) then the new critical frequency = 325-hz*40/16 = 894-hz.
This will also solve the PUMA PMGR problem at 72V nominal but in a safe and reliable way. 10% overclock is acceptable IMO.
Many PUMA owners would be oh so happy.