PropBASIC - PULSOUT - low clock speed

phatallica

Note of caution for PULSOUT with PropBASIC ...
The following code does not work with 5MHz crystal and PLL1X, but does work with PLL2X or higher:

' Use: HCSR04_inch
' --- Pulses TRIG pin for 10us to initiate transmission burst of 40kHz
' --- Reads ECHO pulse to calculate distance
'{$IFUSED HCSR04_inch}
FUNC HCSR04_inch
  PULSOUT TRIG,10             ' initiation pulse
  PULSIN ECHO, 1, __param1    ' measure HIGH time; cannot set timeout, so must wait
  __param1 = __param1 / 148   ' convert to integer inches
  RETURN                      ' returning param1 is implied
ENDFUNC
'{$ENDIF}

The duration of the pulse does not seem to matter, either, as I tried several orders of magnitude. Using PULSOUT with 5MHz just seems to hang-up the code, with the pin HIGH.

I don't see many folks posting code at such low frequency, so maybe I am the only one who has ever noticed this?

---

Side note - PropBASIC Syntax Guide, Version 0.13, page 8 ... the following is shown to demonstrate syntax:

PULSIN Pin, State, Variable {, Timeout}

In this case, the parameter for Timeout is optional.

It seems that Timeout never actually made it into the feature set of PropBASIC. I don't have a practical need for it, but for some reason once I know that I can't have it, I suddenly want it.

Bean

Thanks for the report. I will look into the problem as soon as I can.

Bean

Bean

I can confirm your findings.
The code doesn't actually hang, but it will stop until the hardware counter rolls-over for each microsecond (that could be a LONG time).

Thanks again for pointing it out and I'll have it fixed in the next release of PropBasic.

Bean

phatallica

Bean wrote: »

Thanks again for pointing it out and I'll have it fixed in the next release of PropBasic.

Thanks, Bean.