Re: [Simulavr-devel] How to capture PWM output?

[Stan Behrens]

Hey Jeff,

I wrote a Soft-PWM for up to 8 outputs (one full pin register) that's
using a single Timer-Interrupt to run asynchroniously.

To test my code under hard realtime conditions, I generated some random
PWM-values and recorded the PIN-changes with simulavr's option '-c
vcd:ti:to'.

That option generated a file named 'to' which had timestamp + value of
the pins. Therefor I could calculate all outputted PWM-values with the
PWM-values I wanted, which gave me a full simulated closed loop test setup.

I hope I could help.

Bye, Stan.

On 16/09/2016 15:12, Jeff Lane wrote:
> Hello All, 
> 
>  
> 
> Thank you all for your long and continuing work with simulavr! I am
> successfully using this very useful tool, in both Linux (Debian) and
> Windows(MinGW) environments, and using Python and PyQt for test and GUI
> construction. Setting up Pins and Nets for Digital, Analog, and Serial
> "Pins" are all OK. 
> 
>  
> 
> I've been less successful with PWM output, and am currently using a
> workaround where I am simply setting volatile variables and reading them in
> the Pin::SetInState method. Of course this is missing pretty much the entire
> PWM code and simulation. Below an example of the Evil that I have done. If
> possible, any help on how to actually use the PWM feature in a normal
> Net/Pin setup would be most welcome. 
> 
>  
> 
> P.S: Not related, and I know the TWI interface is not implemented yet, but I
> do watch this kind of thing go by many thousands(?) of times a day! :) : 
> 
>   "WARNING: file rwmem.cpp: line 243: TWI register TWCR not simulated (write
> 0x80 to register)"
> 
>   "WARNING: file rwmem.cpp: line 243: TWI register TWDR not simulated (write
> 0xff to register)" 
> 
>  
> 
> Thank You,
> 
> Jeff
> 
>  
> 
> /**********  current ugly workaround **********/
> 
> /**********  something like this in the source   **********/
> 
>  
> 
> #ifdef SIMULAVR
> 
> volatile int OCR1A_value; 
> 
> volatile int OCR1B_value;
> 
> volatile int PWM_top_value;
> 
> #endif
> 
>  
> 
> Etc.
> 
>  
> 
> /**********  something like this in device MCU **********/
> 
> # Gas PropValve Control  (PWM)
> 
> ## Pin to receive digital data from pin PD5
> 
> self.pinGasControlValve = OutputPinPWM("pinGasControlValve", self.dev,
> "OCR1B_value", 'PWM_top_value')
> 
> ## MCU Pin PD5
> 
> self.pinD5 = self.dev.GetPin("D5")
> 
> ## Net for MCU Pin PD5
> 
> self.netPD5 = pysimulavr.Net()
> 
> self.netPD5.Add(self.pinD5)
> 
> self.netPD5.Add(self.pinGasControlValve)  
> 
>  
> 
>  
> 
>  
> 
> /**********  something like this in Pin  **********/
> 
> ## Class to represent a PWM output (from MCU) Pin. 
> 
> #  
> 
> #
> 
> class OutputPinPWM(pysimulavr.Pin):
> 
>     
> 
>     ## OutputPinPWM constructor     #
> 
>     def __init__(self, pin_name, parent_device, pwm_value_varname,
> pwm_range_varname):
> 
>         pysimulavr.Pin.__init__(self)
> 
>         ## string name of Pin
> 
>         self.myname = pin_name
> 
>  
> 
>         ## reference to parent MCU
> 
>         self.parent_device = parent_device
> 
>  
> 
>         ## reference to pwm_value_varname from MCU source code
> 
>         self.pwm_value_varname = pwm_value_varname
> 
>  
> 
>         ## current PWM range value (for % calculation)
> 
>         self.pwm_range_varname = pwm_range_varname
> 
>  
> 
>         ## calculated PWM value (for application)
> 
>         self.calculated_pwm_value = 0
> 
>  
> 
>         ## current PWM value (for comparison)
> 
>         self.current_pwm_value = 0
> 
>  
> 
>         ## previous PWM value (for comparison)
> 
>         self.old_pwm_value = 0
> 
>       
> 
>     ## return name of the Pin
> 
>     #
> 
>     def __str__(self):
> 
>         return self.myname
> 
>  
> 
>     ## return current PWM value
> 
>     #
> 
>     def getCurrentPvmValue(self):
> 
>         return self.calculated_pwm_value
> 
>     
> 
>     ## Update pin value
> 
>     #
> 
>     def SetInState(self, pin):
> 
>         pysimulavr.Pin.SetInState(self, pin)
> 
>         try:
> 
>            # following code reference from simulavr python examples (
> simulavr/examples/python/ex_utils.py ) 
> 
>            # read current PWM variable direct from MCU  :( 
> 
>             addr =
> self.parent_device.data.GetAddressAtSymbol(self.pwm_value_varname)
> 
>             self.current_pwm_value = self.parent_device.getRWMem(addr)
> 
>             addr += 1
> 
>             self.current_pwm_value = (self.parent_device.getRWMem(addr) <<
> 8) + self.current_pwm_value
> 
>  
> 
>            # read current PWM range variable direct from MCU  :( 
> 
>             addr =
> self.parent_device.data.GetAddressAtSymbol(self.pwm_range_varname)
> 
>             pwm_max_value = self.parent_device.getRWMem(addr)
> 
>             addr += 1
> 
>             pwm_max_value = (self.parent_device.getRWMem(addr) << 8) +
> pwm_max_value
> 
>  
> 
>             if self.current_pwm_value != self.old_pwm_value:
> 
>  
> 
>                 self.old_pwm_value = self.current_pwm_value
> 
>  
> 
>                 # calculate pwm percentage
> 
>                 if (pwm_max_value != 0):
> 
>                     self.calculated_pwm_value =
> (float(self.current_pwm_value) / pwm_max_value ) * 100
> 
>                 else:
> 
>                     self.calculated_pwm_value = 0
> 
>  
> 
>                 print ("OutputPinPWM SetInState : calculated_pwm_value = " +
> str(self.calculated_pwm_value)) 
> 
>  
> 
>                 # send blinker signal with updated PWM value
> 
>                 pin_message = signal(self.pwm_value_varname)
> 
>                 pin_message.send(self, message=self.calculated_pwm_value,
> signal_name=self.myname)
> 
>                 print "pin_message.send (" + self.myname + " : " +
> self.pwm_value_varname + "): " + str(self.calculated_pwm_value) 
> 
>  
> 
>  
> 
>         except Exception as err:
> 
>             print ("OutputPinPWM Error:SetInState : " + str(err)) 
> 
>  
> 
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