dstroy0
Zeroes and Ones
Growing stuff and doing things
- Thread starter dstroy0
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dstroy0
Zeroes and Ones
something something monsters ahead
It's prolly fine. Who needs memory?
lol
I'm running through refactoring things today. So I'll probably end up doing regression testing later today or tomorrow.
Simple debugging and refactoring. I just run bits of code and time them, move class members up or down and rerun, maybe try and rearrange formulas to not have to deal with float division which takes an eternity on this microcontroller.
It's prolly fine. Who needs memory?
lol
I'm running through refactoring things today. So I'll probably end up doing regression testing later today or tomorrow.
Simple debugging and refactoring. I just run bits of code and time them, move class members up or down and rerun, maybe try and rearrange formulas to not have to deal with float division which takes an eternity on this microcontroller.
dstroy0
Zeroes and Ones
Space-dumpsters unite!
dstroy0
Zeroes and Ones
I fixed a fun little problem yesterday,
On the arduino mega, they used two different types of pwm by default. TCCR0 is the timer that generates millis(), delay() etc. It's one you don't want to mess with unless you don't need certain built in functionality. It uses fast PWM which counts up to 255 and then gets reset to 0.
The other timers use phase-correct PWM differs from fast PWM in a couple of ways but importantly it counts up to 255, then counts back down to 0. but not always. Sometimes it misses a cycle? I'm not really sure whats happening. You can observe the behavior on an oscilloscope, running PWM on pins from TCCR0 and any of the other TCC2-5. What it does is make like a little beat flicker when it's out of phase.
It's ridiculously easy to fix. You just set any other TCC you have connected to fast PWM and any flicker will be gone, or outside the refresh rate of your eyeballs.
For me, I'm using pin 4 (TCC0) and pin 9 (TCC2), I had to set TCCR2 to fast PWM.
On the arduino mega, they used two different types of pwm by default. TCCR0 is the timer that generates millis(), delay() etc. It's one you don't want to mess with unless you don't need certain built in functionality. It uses fast PWM which counts up to 255 and then gets reset to 0.
The other timers use phase-correct PWM differs from fast PWM in a couple of ways but importantly it counts up to 255, then counts back down to 0. but not always. Sometimes it misses a cycle? I'm not really sure whats happening. You can observe the behavior on an oscilloscope, running PWM on pins from TCCR0 and any of the other TCC2-5. What it does is make like a little beat flicker when it's out of phase.
It's ridiculously easy to fix. You just set any other TCC you have connected to fast PWM and any flicker will be gone, or outside the refresh rate of your eyeballs.
For me, I'm using pin 4 (TCC0) and pin 9 (TCC2), I had to set TCCR2 to fast PWM.
Code:
//arduino mega2560
//non-inverting fast pwm pin 9/10
bitSet(TCCR2A, COM2A1);
bitClear(TCCR2A, COM2A0);
bitSet(TCCR2A, COM2B1);
bitClear(TCCR2A, COM2B0);
bitSet(TCCR2A, WGM21);
bitSet(TCCR2A, WGM20);
bitClear(TCCR2B, WGM22);
Cool stuff, just starting to read/play with the pulse width modulation stuff...hope you don't mind the question 
Does phase correct PWM divide the frequency by two compared to fast PWM? because the timer is going both up and down. Would you divide by 255 or 256? I think I read something about a 1 off rule..
Does phase correct PWM divide the frequency by two compared to fast PWM? because the timer is going both up and down. Would you divide by 255 or 256? I think I read something about a 1 off rule..
dstroy0
Zeroes and Ones
Cool stuff, just starting to read/play with the pulse width modulation stuff...hope you don't mind the question
Does phase correct PWM divide the frequency by two compared to fast PWM? because the timer is going both up and down. Would you divide by 255 or 256? I think I read something about a 1 off rule..
pp 174 in the datasheet for an atmega2650
The N variable represents the prescale factor (1, 8, 32, 64, 128, 256, or 1024).
dstroy0
Zeroes and Ones
You're welcome! That was just for TCC2, an 8 bit TCC on the MCU I'm using. The other counters might use different formulae!
dstroy0
Zeroes and Ones
I got it from mama funk. It’s the apothecary genetics grape ape, smells and tastes like grape candy, smooth smoke. It works so good for anxiety.
