How to change PWM Frequency?

i need to change the frequency of the pwmgen during runtime.
Unfortunately this does not work. I cannot link hm2_7i92.0.pwmgen.pwm_frequency to a signal.
For that, pwm_frequency would have to be a pin and not a parameter.



How can I change the pwm frequency with a singal?

--
Roland

Yes, HM2 PWM frequency is a parameter not a pin so it cannot be linked to a signal
If its just changed occasionally you can use a script with setp

What is the application? maybe PWM is not the best solution.

A solenoid valve regulates the flow. The valve is opened 10 times per second for a short time.

So far I do this with pwmgen.

PWM Frequency = 10 Hz

Value 0,062 results in a pulse width of 6.2 ms
...
Value 0.014 results in a pulse width of 1.4 ms

Up to here everything is fine.

At Value < 0.014 the pulse width becomes < 1.4 ms.

But a smaller pulse width than 1.4 ms cannot switch the valve.
To be able to work with value < 0.014, the frequency must be reduced here.

At that low a frequency you are probably better of using software PWM
perhaps siggen and oneshot, or it may be that the software PWM
will work with pwmgen.0.dither-pwm set true (and a 500 Hz thread so
the minimum pulse width is never less than 2 ms)

Another option is using the rcpwmgen (made for RC servos) this has
a rate pin and a .01 to 1KHz PWM rate

man hostmot2

oneshot and siggen I have tested. That works. The problem is that the pulse width is always a multiple of 1 ms. This is too inaccurate.

Is a new bit file necessary for rcpwmgen?

Attached is my current .vhd file. What must be changed here?

Basically just the module and the pin name, but I just realized a limitation of the rcpwmgen
that may make it an issue, the maximum pulse width is ~10 ms, what is you maximum pulse width?

maximum pulse width is 6.2 ms

OK then it should work,
The new module line would be:

(RCPWMTag, x"00", ClockLowTag, x"01", RCPWMWidthAddr&PadT, RCPWMNumRegs, x"00", RCPWMMPBitMask),

and the new pin line would be:

IOPortTag & x"00" & RCPWMTag & RCPWMOutPin,

I was not able to generate the bitfile.
I get this error message:

Can you support me a bit more?

Sounds like you don't have the latest source

constant RCPWMTag : std_logic_vector(7 downto 0) := x"2C";
constant RCPWMOutPin : std_logic_vector(7 downto 0) := x"81";

are in the current IDROMConst.vhd