500 Khz

[IhsanFuadi3]

Hi in the nucleo f446 the speed of each axis can be up to 500 khz? thanks before

[Schildkroet]

Hello, i never tried, but i think it should be possible. But you have to change max_step_rate https://github.com/Schildkroet/GRBL-Advanced/blob/software/grbl/Config.h#L313-L317

[IhsanFuadi3]

thank for you reply sir, I change max_step_rate and F_CPU in util.h,and it's working

[Schildkroet]

You shouldn't change F_CPU unless you actually change the clock tree. Otherwise grbl won't calculate step rates etc correct

[IhsanFuadi3]

you mean possible miss step?

[Schildkroet]

No, wrong feedrate etc

[IhsanFuadi3]

oo i see,but if i just change max _step_rate,grbl only up to 250 khz,how i increase more than 250 khz?

[Schildkroet]

Double timer frequency here https://github.com/Schildkroet/GRBL-Advanced/blob/software/HAL/TIM/TIM.c#L147-L155 https://github.com/Schildkroet/GRBL-Advanced/blob/software/grbl/util.h#L46

[IhsanFuadi3]

if may i know,how calculate timer frequancy,if I want 500 khz sir?

[Schildkroet]

TIM_TimeBaseStructure.TIM_Prescaler = 7-1; // 24 MHz

Change to : TIM_TimeBaseStructure.TIM_Prescaler = 3; // 48 MHz

F_TIMER_STEPPER 48000000UL

[IhsanFuadi3]

i use Nucleo F446 sir

[IhsanFuadi3]

is there any problem if i set max_step_rate to 500000 Khz sir?with your suggest frequency

[Schildkroet]

I didn't tried it yet. You have to find out yourself

[IhsanFuadi3]

Ok Sir,thanks for the reply