how to get around the 15 parameter error

KeyBoard · 2013-05-25 09:37

Hello, I have been trying to update my 3dof quad program recently so that it can easier to calibrate the servos when I get better ones and I ran into a problem, that is I need to pass the pin values and servo offsets for all the servos (a parameter count of 24) to another object and there is a limet of 15 that I can pass is there any way that I can get around this or am I doomed. kind regards.

JonnyMac · 2013-05-25 09:44

When I have more than 5 parameters I pass the address of a block of values in a DAT section:

object.start(@ParameterList)

With the list built like this:

dat

  ParameterList         byte    1, 2, 3, 4, 5, 6

Of course, the code in the .start method needs to know how to deal with the list, but that's easy:

pub start(p_params)

  pinX := byte[p_params][0]
  pinY := byte[p_params][1]

KeyBoard · 2013-05-25 09:45

thanks I will try that

Mike Green · 2013-05-25 10:09

Since parameters are always long values and I/O pin numbers are a byte or less, I've sometimes passed them packed together in a long. This works particularly well when the pin numbers are defined as constants in the main object. You can get six pin numbers in one long value this way like this:

CON pinA = 5
    pinB = 8
    pinC = 10
    pinD = 15
    pinE = 21
    pinF = 25
    allPins = pinA<<25 | pinB<<20 | pinC<<15 | pinD<<10 | pinE<<5 | pinF

You'd pass allPins to your start method and unpack it in a loop like this:

pub start( myPins) | i, pins[6]
   repeat i from 0 to 5
      pins[ i ] := (myPins >> (25 - i*5)) & 31

This is not a particularly efficient way to do this, but it will work and illustrates the technique.

how to get around the 15 parameter error

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