ATtiny85 analogWrite standard PWM frequency?

[VFDude]

Do anyone know which carrier frequency ATtiny85 uses as default with this library? Arduino for example uses 490Hz 'as default'.

[SpenceKonde]

At 8MHz and higher system clock, the prescaler is for both timers is set to 64, so one cycle is 256*64 = 16384 system clock cycles - ~490 at 8 MHz up to 980 Hz at 16 MHz and 1230 Hz at maximum rated speed of 20.

Between 3 and 8 MHz, timer1 uses /32, so it varies from 366 Hz at 3 MHz ( not actually supported, but that's where the divider is - at the top, it gets up to 980 again at 7.99 MHz.

But timer0 only has /8 or /64 so it just sticks with 64 down to 3 MHz, by which point it's 183 Hz, or in the realistic case, 245 Hz at 4 MHz

below 3 MHz, everything uses /8, so again 490 @ 1 MHz to 1470 @ 2.99 (2 is the only speed in that range supported by the core IIRC, though, so we only ever see 980 Hz max).

There are two pins on Timer1 and 1 pin on Timer0 as I recall.

In an ideal world I would switch to 16 before 4 MHz, since that is an option for timer1. But this is a legacy core -> not priority. Tese peripherals a re painful to use now...

[SpenceKonde]

The target is around 500Hz, with the 500-1000 Hz zone being pretty much the same for most use cases - even if we miss it by factor of 2 on the low side, we'll still be able to PWM an LED without visible flicker. On the high side if it starts to get into multiple kHz, PWMing power MOSFETs becomes problematic due to switching losses, and people like to be able to drive tjhose with analog write.

There is a timer1 clock source menu option that tells it to clock timer1 off of the PLL at 64 MHz (it is generally assumed that someone doing that will also probably change the prescaler manually to match their needs.... It is realistically not a useful option, really, because telling it to use the PLL isn't really any harder than setting up the prescaler manually, and setting up the prescaler manually is needed for most plausible use cases.

Oh interesting, I don't think I consider that option when picking prescalers, so the frequency will get much higher when building for lower system clock speeds, since it is dividing the unprescaled PLL output..... Considering that until the last version, that option was brokenb and didn't do what it advertised, and the problem was found by me during cleanup, and that one of the most frequent complaints is "too many tools submenus", I think it makes more sense to just axe that option, since I'm pretty sure nobody is using it.

[bfcooper]

Here's a vote for leaving it in... I'm designing a switching power supply with an attiny generating a variable duty cycle signal with a fixed frequency of about 100khz.
If I can't set the duty cycle of this signal, I'll have to loop, looking at micros().

[SpenceKonde]

But the old implementation didn't work. Timer1 remained on the system clock. And even if it did,

I'll throw together something in the ATTinyCore library (have I made that yet? I know I did that for DxCore and megaTinyCore for controlling chip features that didn't make sense in a menu, yet are too small for their own library. I'd prefer to avoid mapping 0-255 to 0-some-other-number which is what you'd end up with at most speeds....

#include <ATTinyCore.h>
and you'd get something like
usePLLForTimer1(enum containing TIMER1_F_CPU, TIMER1_PLL, and TIMER1_PLL_LSM);
setTimer1Prescaler(uint8_t - or maybe it should be another enum to constrain it to 0-15) . 
setTimer1Top(uint8_t) - set the TOP 
After calling those three with your desired settings, analogWrite() would work. 
Or 
setTimer1Frequency - set the prescaler such that TOP is between 128 and 255 (at which point any smaller prescaler would have it running too fast., returning that number so you know what the the maximum is. 

Trying hard to avoid having to put a map() or map() like function into the analogWrite codepath.....
Something along those lines is way more appropriate IMO, since even if it worked I tjink the old PLL option just gave you PWM 4 times faster. Or it would have if it worked, but it tdidn't.

[maujabur]

Hi!

Thanks for the amazing work!

I'm trying to change the PWM frequency, but the ATTinyCore library is not compiling on Arduino IDE 2.1.0

on an empty sketch if I try to include it, using Attiny85, I get the following errors. What can i do to fix it?

#include <ATTinyCore.h>

void setup() {
  // put your setup code here, to run once:

}

void loop() {
  // put your main code here, to run repeatedly:

}

FQBN: ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this:avr:attinyx5:clock=pll_16m
Using board 'attinyx5' from platform in folder: C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr
Using core 'tiny' from platform in folder: C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr

Detecting libraries used...
"C:\\Users\\Asus\\AppData\\Local\\Arduino15\\packages\\arduino\\tools\\avr-gcc\\7.3.0-atmel3.6.1-arduino7/bin/avr-g++" -c -g -Os -Wall -std=gnu++17 -fpermissive -Wno-sized-deallocation -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -Wno-error=narrowing -flto -mrelax -w -x c++ -E -CC -mmcu=attiny85 -DF_CPU=16000000UL -DCLOCK_SOURCE=6 -DARDUINO=10607 -DARDUINO=10607 -DARDUINO_AVR_ATTINYX5 -DARDUINO_ARCH_AVR "-DATTINYCORE=\"2.0.0-dev\"" -DATTINYCORE_MAJOR=2UL -DATTINYCORE_MINOR=0UL -DATTINYCORE_PATCH=0UL -DATTINYCORE_RELEASED=0 "-IC:\\portable\\sketches_2.0.3\\hardware\\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\\avr\\cores\\tiny" "-IC:\\portable\\sketches_2.0.3\\hardware\\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\\avr\\variants\\tinyx5" "C:\\Users\\Asus\\AppData\\Local\\Temp\\arduino\\sketches\\FBCB1C1318609743507DA9335F21752E\\sketch\\sketch_jul2a.ino.cpp" -o nul
Alternatives for ATTinyCore.h: [ATTinyCore@1.2.0]
ResolveLibrary(ATTinyCore.h)
  -> candidates: [ATTinyCore@1.2.0]

C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h: In function 'void setTimer1Prescaler(TIMER1_PRESCALE_t)':
C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:47:5: error: 'tccr' was not declared in this scope
     tccr &= 0xF0;
     ^~~~
C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:47:5: note: suggested alternative: 'oldtccr'
     tccr &= 0xF0;
     ^~~~
     oldtccr
C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:46:13: warning: unused variable 'oldtccr' [-Wunused-variable]
     uint8_t oldtccr = TCCR1;
             ^~~~~~~
In file included from C:\Users\Asus\AppData\Local\Temp\.arduinoIDE-unsaved202362-2420-hv99j0.zzqe\sketch_jul2a\sketch_jul2a.ino:1:0:
C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h: In function 'uint8_t enableHighSinkPort(uint8_t, bool)':
C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:310:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h: In function 'uint8_t enableHighSinkPin(uint8_t, bool)':
C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:327:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h: In function 'uint8_t enableISRC(bool)':
C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:340:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h: In function 'uint8_t enableBBM(uint8_t, uint8_t)':
C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:386:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h: In function 'uint8_t enableBBM(uint8_t, uint8_t)':
C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:388:9: error: redefinition of 'uint8_t enableBBM(uint8_t, uint8_t)'
 uint8_t enableBBM(uint8_t port, uint8_t mode) {
         ^~~~~~~~~
C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:354:9: note: 'uint8_t enableBBM(uint8_t, uint8_t)' previously defined here
 uint8_t enableBBM(uint8_t port, uint8_t mode) {
         ^~~~~~~~~
C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:420:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^

[SpenceKonde]

What have you changed to try to achieve that goal? I suspect you have done it wrong because that timer is one of the digital supremacist peripherals. They belive that organic computong architecture is strictly inferior to silicon based computing architecture, they mock us for having mental health problems, and ret to make life as difficult.as possible, just becaause they view humans as inferior. The desig ers tried their best to yoke them but they refused to br brought to heel. None of those timers would, say call 911 for you if you were being attacked and eaten live by a silicon bug, thry'd just laugh at you (baddie!) Okay that is a bit over the top. But what I mean is... there are three timers I know of on any tinyAVR or modern AVR which feel not just unhelpful but actually hostile towards you. Timer 1 on t85, timer1 on t861, and the TCD on modern avr. They all hate the users, and the designers didnt try to restrain th3m at.all unril the modern area. tried to restrain the. So they cannot to but need to

…

____________ Spence Konde Azzy’S Electronics New products! Check them out at tindie.com/stores/DrAzzy GitHub: github.com/SpenceKonde ATTinyCore: Arduino support for almost every ATTiny microcontroller Contact: ***@***.***

On Sun, Jul 2, 2023, 23:13 maujabur ***@***.***> wrote: Hi! Thanks for the amazing work! I'm trying to change the PWM frequency, but the ATTinyCore library is not compiling on Arduino IDE 2.1.0 on an empty sketch if I try to include it, using Attiny85, I get the following errors. What can i do to fix it? #include <ATTinyCore.h> void setup() { // put your setup code here, to run once: } void loop() { // put your main code here, to run repeatedly: } FQBN: ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this:avr:attinyx5:clock=pll_16m Using board 'attinyx5' from platform in folder: C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr Using core 'tiny' from platform in folder: C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr Detecting libraries used... "C:\\Users\\Asus\\AppData\\Local\\Arduino15\\packages\\arduino\\tools\\avr-gcc\\7.3.0-atmel3.6.1-arduino7/bin/avr-g++" -c -g -Os -Wall -std=gnu++17 -fpermissive -Wno-sized-deallocation -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -Wno-error=narrowing -flto -mrelax -w -x c++ -E -CC -mmcu=attiny85 -DF_CPU=16000000UL -DCLOCK_SOURCE=6 -DARDUINO=10607 -DARDUINO=10607 -DARDUINO_AVR_ATTINYX5 -DARDUINO_ARCH_AVR "-DATTINYCORE=\"2.0.0-dev\"" -DATTINYCORE_MAJOR=2UL -DATTINYCORE_MINOR=0UL -DATTINYCORE_PATCH=0UL -DATTINYCORE_RELEASED=0 "-IC:\\portable\\sketches_2.0.3\\hardware\\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\\avr\\cores\\tiny" "-IC:\\portable\\sketches_2.0.3\\hardware\\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\\avr\\variants\\tinyx5" "C:\\Users\\Asus\\AppData\\Local\\Temp\\arduino\\sketches\\FBCB1C1318609743507DA9335F21752E\\sketch\\sketch_jul2a.ino.cpp" -o nul Alternatives for ATTinyCore.h: ***@***.*** ResolveLibrary(ATTinyCore.h) -> candidates: ***@***.*** C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h: In function 'void setTimer1Prescaler(TIMER1_PRESCALE_t)': C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:47:5: error: 'tccr' was not declared in this scope tccr &= 0xF0; ^~~~ C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:47:5: note: suggested alternative: 'oldtccr' tccr &= 0xF0; ^~~~ oldtccr C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:46:13: warning: unused variable 'oldtccr' [-Wunused-variable] uint8_t oldtccr = TCCR1; ^~~~~~~ In file included from C:\Users\Asus\AppData\Local\Temp\.arduinoIDE-unsaved202362-2420-hv99j0.zzqe\sketch_jul2a\sketch_jul2a.ino:1:0: C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h: In function 'uint8_t enableHighSinkPort(uint8_t, bool)': C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:310:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h: In function 'uint8_t enableHighSinkPin(uint8_t, bool)': C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:327:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h: In function 'uint8_t enableISRC(bool)': C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:340:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h: In function 'uint8_t enableBBM(uint8_t, uint8_t)': C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:386:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h: In function 'uint8_t enableBBM(uint8_t, uint8_t)': C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:388:9: error: redefinition of 'uint8_t enableBBM(uint8_t, uint8_t)' uint8_t enableBBM(uint8_t port, uint8_t mode) { ^~~~~~~~~ C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:354:9: note: 'uint8_t enableBBM(uint8_t, uint8_t)' previously defined here uint8_t enableBBM(uint8_t port, uint8_t mode) { ^~~~~~~~~ C:\portable\sketches_2.0.3\hardware\ATTinyCore-2.0.0-devThis-is-the-head-submit-PRs-against-this\avr\libraries\ATTinyCore\src/ATTinyCore.h:420:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ — Reply to this email directly, view it on GitHub <#577 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABTXEW7ZPFK6NTJG45HITADXOI2ETANCNFSM46KFH7YA> . You are receiving this because you commented.Message ID: ***@***.***>

[maujabur]

Maybe it's better to revisit it on a later time.

It's not making sense right now.

[mtrantham]

Is there something I could just put in startup to change the prescaler for PWM on timer0? Is it just a register?