Closed Pourya-3deo closed 4 months ago
This is a known limitation, present because the timer/counter channels on the SAME70 processor are only 16 bits wide and the range of input clocks available is limited. The timer channels currently use a 150MHz clock divided by 128, so the minimum available PWM frequency is 150MHz/(128*65535) = 17.88Hz. We may be able to reduce the minimum frequency to 11.44Hz by switching to a different clock.
The PWM-capable outputs on the 6HC that are drive by timer/counter channels on the 6HC are: OUT4 OUT5 OUT8 OUT7 IO4.OUT IO5.OUT IO7.OUT
The PWM-capable outputs on the 6HC that are driven by the PWM peripheral and have a lower minimum frequency are: OUT0 OUT1 OUT2 OUT3 OUT6 OUT9
Thank you for your email, I was worried about that and hoped for a solution, is there any software based PWM with a macro maybe?
On Fri, Apr 19, 2024 at 2:04 AM dc42 @.***> wrote:
This is a known limitation, present because the timer/counter channels on the SAME70 processor are only 16 bits wide and the range of input clocks available is limited. The timer channels currently use a 150MHz clock divided by 128, so the minimum available PWM frequency is 150MHz/(128*65535) = 17.88Hz. We may be able to reduce the minimum frequency to 11.44Hz by switching to a different clock.
The PWM-capable outputs on the 6HC that are drive by timer/counter channels on the 6HC are: OUT4 OUT5 OUT8 OUT7 IO4.OUT IO5.OUT IO7.OUT
The PWM-capable outputs on the 6HC that are driven by the PWM peripheral and have a lower minimum frequency are: OUT0 OUT1 OUT2 OUT3 OUT6 OUT9
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If you need a lower PWM frequency than 18.8Hz then use one of the outputs that is controlled by the PWM peripheral, which I listed in my reply above.
So I tried OUT0 and OUT9 but I don't get any accurate square shaped signal. Here is the code: Config: M950 P10 C"out9" Q10 Macro: M42 P10 S0.5
Duet Forum Discussion Thread
I tried I couldn't register
Which Duet products are you using?
Firmware Version
RRF 3.5.0
Duet Web Control Version
DWC 3.4.6
Are you using a Single Board Computer (RaspberryPi) with your Duet?
Please upload the results of sending M122 in the gcode console.
Please upload the content of your config.g file.
Please upload the content of any other releveant macro files.
Details specific to your printer.
Our own 3d printer
Links to additional info.
No response
What happened?
Expected result Frequency should be 10 HZ
Observed result Frequency was 17.88 HZ
Steps to reproduce