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Digital pin 10 on arduino mega 25602/18/2024 ![]() ![]() You could set up an interrupt service routine to run triggered by a timer, and whenever it runs it manually turns specific pins on or off as required by your PWm needs. Quote from: Infraviolet on January 20, 2023, 02:47:08 am IF you can cope with having your software which runs on the arduino spend a lot of its clock cycles on manually toggling pins then you can bitbang out PWM on any pin you want, how much of a strain it will put on doing the other things your program tries to do depends on how fast a frequency you want to apply the PWM to. elefurtronik, for a brushed DC motor why do you need more than 1 channel of PWM? Unless you are running twenty separate motors, or giving PWM to 20 separate PWM controlled servo motors which just hapen to have brushed DC motors within them? A h-bridge driver (which lets you easily reverse and do coasting versus sudden braking) chip might be more to your liking than a MOSFET here too, h-bridge chips are designed with logic level inputs in mind, no need to worry about exact gate voltages. This becomes even worse if you are taking a pin high and low using PORTx register single clock cycle operation commands which don't have the same logic around them as digitalWrite() does (these methods can be really useful where an arduino compatible microcontroller's putput needs to change rather fast though, digitalWrite() is pretty slow). In my experience, calling digitalwrite() on the same pin as you are PWMing may sometimes have unexpected effects. The alterantive for having many PWm channels would be to buy an I"c or SPi controllable PWM generator chip, or buy a microcontroller which you would program to be an I2C/SPI slave and perform this same role. The number of possible cases can be extended and if you would be to do some testing I’d be happy to extend the 6PWM support to all pwm pins.IF you can cope with having your software which runs on the arduino spend a lot of its clock cycles on manually toggling pins then you can bitbang out PWM on any pin you want, how much of a strain it will put on doing the other things your program tries to do depends on how fast a frequency you want to apply the PWM to. Otherwise they will be out of sync.Īs the mega support is still a bit undertested, there might be some issues and one of them that I see now is that there is only one pwm pin combinations supported for 6 pwm. Now to be able to use the 6 pwm on arduino mega you need to use the high and low pair pins which belong to the same timer. This is a problem of arduino implementation only, so the line 143 is the fix for these spetial cases. However, in some cases setting pwm to 255 or 0 does not use analogWrite internally but a digitalWrite and this digital write is not inverted. ![]() So when we’re setting the pwm we dont have to do any additional invertion. Hey mega as well as most of atmega chips support hardware invertion of pwm output. I’m so excited by this project, and I’m trying to learn a lot at the same time. Lastly, are all PWM pins supported here? I am using these: ![]() ![]() Any explanation is hugely appreciated and only for my better understanding.Īlso, am I correct in that hardware inverting (NOT gate) the high PWM signal is not an acceptable solution? Won’t this mess up dead time? Doesn’t digitalWrite(pinL, pwm_l ? LOW : HIGH) turn the pin off when the duty cycle is 255? I ask about this segment because I am unsure if the Mega is supported, and this code could possibly be out of date or something? Just checking. This leads me to believe that the signal is not inverted.Īs a side note, (and I don’t fully understand how the 3-phase transition works) the line 143 does not seem correct to me. In _setPwmPair I see that both high and low PWM get set the same val duty cycle, with opposing adjustments of dead_time. In src/drivers/hardware_specific/atmega2560_mcu.cpp I see that _writeDut圜ycle6PWM calls _setPwmPair. I have crappy oscilloscope skills and cant seem to tune mine in at the moment… Browsing the code, it looks like not. I have been trying to figure out if the 6 pin mode inverts the PWM signal in the micro controller or not. Currently, I’m running open-loop because I don’t have any sensing method possible yet. Didn’t see anywhere if this was officially supported, but I’ve been having mild success. I’ve been trying 6 Pin PWM on the Arduino Mega. ![]()
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