Writing a needet HAL Component

Emanresu
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7 years 2 months ago #143180 by Emanresu

Writing a needet HAL Component was created by Emanresu

Hello there,

im looking for an Timer. Something like sending a siggen signal to an encoder.
Just more simple in a single threat.
Im curious how hard it is to write (im no coder at all)

Example:

loadrt u32runner [count=N|names=name1[,name2...]]

runner.N.run bit in => run
runner.N.from u32 in => Number to start =>(just nice to have)
runner.N.to u32 in => Number to count to =>(if there is no "from" this can also be "THE" number)
runner.N.speed s32 in => count speed =>(must have - can also be an u32 if in ms)
runner.N.cycle bit in => repeat yes/no =>(must have)
runner.N.rev bit in => count backwards =>(just nice to have)
runner.N.warp bit in => one way or up and down =>(one way is need, up and down is nice to have)
runner.N.out u32 out => output =>(need of course)

For the first test its for the Owl in my panel. Its an 3D rendered objekt framed in single jpegs to an image_u32.

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Also im open vor every other idea!

Greetings
Emanresu

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cmorley
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7 years 2 months ago #143188 by cmorley

Replied by cmorley on topic Writing a needet HAL Component

Can you write pseudo code (description) of how you want it to work, rather then the pin description?

If you have no coding experience at all, it will be a bit challenging, but possible.
There is probably a component available to base it from.
Chris M

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rodw
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7 years 2 months ago #143192 by rodw

Replied by rodw on topic Writing a needet HAL Component

Probably something like this. I did not think rev was required so left it out. Please run through dos2unix as it was written in Windows.

There are probably typos

Attachment not found

We set up some static variables that will persist between servo thread loops

We do a firstpass to check the cycle is a positive value. This might need revising if you change this value in real time (eg move it into the run loop

then an outer loop so it only runs if run is true
So then we need to skip cycle periods so we go into a do.. while loop. (It is very rare for me to actually use a do loop)
once we have counted the required number of cycles, we reset this_cycle to 0 to start again next time.
we determine which direction we need to be stepping from to the destination to
There are more efficient ways to write this but that would defeat the purpose if you are trying to learn.

eg the if statement to change step value could be written

Code:

step = (step > 0 ? -1 : 1)

but I will leave that as an exercise for the student to research and learn about C's ternary operator

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Emanresu
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7 years 2 months ago #143227 by Emanresu

Replied by Emanresu on topic Writing a needet HAL Component

Hi and thx for tha fast response!

Well, the component "time" would be nice, if it just hat 0,1 seconds.

Example Code:

pyVCP

Code:

<vbox>
	<checkbutton> <font>("Arial",12)</font> <halpin>"run"</halpin> </checkbutton>
	<image_u32 halpin='selectimage' images='1 2 3 ... 27 28 29 30'/>
	<image name='1' file='./My-Panel/EuleAnim/0001.png'/>
			...
	<image name='1' file='./My-Panel/EuleAnim/0030.png'/>
</vbox>

HAL

Code:

loadrt runner count=1
addf runner servo-thread

setp runner.0.to	30
setp runner.0.speed	100
setp runner.0.cycle	1       #(1=cycle 2=count only once)

net start => runner.0.run
net start <= pyvcp.run

net number => pyvcp.selectimage
net number <= runner.0.out

Rodw thx vor the example! Cant wait to look into it!
Maybe some more need something like that and we crate a new component for new releases

As i sayd above, i have no idea if it need to be complex. The timer.comp is verry close to what i need.

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Emanresu
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7 years 2 months ago #143245 by Emanresu

Replied by Emanresu on topic Writing a needet HAL Component

Ok....

i used Notepad++ to konvert from CL + LF to LF only.

This is what i get in LinuxCNC:

voxters@Vox-CNC:~/Arbeitsfläche$ halcompile --install runner.comp
make KBUILD_EXTRA_SYMBOLS=/usr/realtime-3.4-9-rtai-686-pae/modules/linuxcnc/Module.symvers -C /usr/src/linux-headers-3.4-9-rtai-686-pae SUBDIRS=`pwd` CC=gcc V=0 modules
make[1]: Entering directory `/usr/src/linux-headers-3.4-9-rtai-686-pae'
CC [M] /tmp/tmpTmai2A/runner.o
runner.comp: In function '_':
runner.comp:41:2: error: initializer element is not constant
runner.comp:47:10: error: lvalue required as left operand of assignment
runner.comp:53:16: error: expected ')' before ';' token
runner.comp:54:3: error: expected ';' before '}' token
runner.comp:54:3: error: expected 'while' before '}' token
runner.comp:56:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
runner.comp: At top level:
runner.comp:83:1: error: expected identifier or '(' before '}' token
make[4]: *** [/tmp/tmpTmai2A/runner.o] Fehler 1
make[3]: *** [_module_/tmp/tmpTmai2A] Fehler 2
make[2]: *** [sub-make] Fehler 2
make[1]: *** [all] Fehler 2
make[1]: Leaving directory `/usr/src/linux-headers-3.4-9-rtai-686-pae'
make: *** [modules] Fehler 2

If i look into the code, my head seems to be in *.xml mode. I totally understand not a single line.
Google leads me to forums to find help...
Help like "This is so common, just google it" and im in a loop xD

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rodw
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7 years 2 months ago #143249 by rodw

Replied by rodw on topic Writing a needet HAL Component

Well, the line numbers are quoted where the errors are.
It does not like the way I say
static int counter = from
becasue from is a variable

Line 52 where I say do, I used a bracket, not a {
Line 56, I forgot a { on the if statement

So other than simple syntax errors

the only one to worry about is the initialisation of counter
so change it to

Code:

        static int counter = 0;
	static int is_warping = 0;

        if(counter == 0) 
              counter = from;

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Emanresu
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7 years 2 months ago #143250 by Emanresu

Replied by Emanresu on topic Writing a needet HAL Component

Where can i donate you???

Ok, i havent testet it yet. But its compiled and shows up in HAL.

for
runner.comp:47:10: error: lvalue required as left operand of assignment
i changed cycle = 1; to cycle == 1;

then i got this:
runner.comp:47:10: warning: value computed is not used [-Wunused-value]
Important?

Also i wasnt sure about

Code:

if(counter == 0) 
              counter = from;

so i did this;

old:

Code:

		else{
			if(counter == from){
				is_warping = 0;
					if(step > 0)
						step = -1;
					else
						step = 0;		

new:

Code:

		else{
			if(counter == 0){
                                counter = from;
				is_warping = 0;
					if(step > 0)
						step = -1;
					else
						step = 0;		

Was that right?

UPDATE

Doesnt work, but seems verry verry close! Error seems to be in line 47

Warning: Spoiler!

Code:

component runner "LinuxCNC runner";

description
"""
Example:

loadrt u32runner [count=N|names=name1[,name2...]]

runner.N.run bit in => run
runner.N.from u32 in => Number to start =>(just nice to have)
runner.N.to u32 in => Number to count to =>(if there is no "from" this can also be "THE" number)
runner.N.speed s32 in => count speed =>(must have - can also be an u32 if in ms)
runner.N.cycle bit in => repeat yes/no =>(must have)
runner.N.rev bit in => count backwards =>(just nice to have)
runner.N.warp bit in => one way or up and down =>(one way is need, up and down is nice to have)
runner.N.out u32 out => output =>(need of course)
""";

author "Rod Webster";

// Example Calibration Data: 0v = 122.9 kHz, 10v = 925.7 Khz should be entered as 122900 and 925700
pin in  bit run          			"count if true";
pin in  signed from                 "number to count from";
pin in  signed to                   "number to count to";
pin in  signed speed = 1          "number of cycles between counts (default = 1 = one servo thread cycle)";
pin in  bit cycle = 1               "if true, start again or stop";
pin in  bit warp                    "if true, count up and then back down";
pin out unsigned out                "the number to output";


function _;
license "GPL";
;;
#include <rtapi_math.h>


FUNCTION(_) {
	static int first_pass = 1;
	static int this_cycle = 0;
	static int step = 1;
	static int counter = 0;
	static int is_warping = 0;
	
	if(first_pass){
		//set up
		if(cycle < 1){
			cycle == 1;
			first_pass = 0;
		}
	}
	if(run){
		do{
			this_cycle++;
		}while(this_cycle < cycle);
		this_cycle = 0;
		if(!is_warping){
			if(from > to)		// Set the direction to count 
				step = -1;
			else
				step = 1;
			counter += step;
			if(step == from){	// we go to the destination
				counter = from;	// stop counting
				if(warp){
					is_warping = 1;
					if(step > 0)
						step = -1;
					else
						step = 0;
				}
			}
		}
		else{
			if(counter == 0){
				counter = from;
				is_warping = 0;
					if(step > 0)
						step = -1;
					else
						step = 0;				
			}
		}
	}
}

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rodw
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7 years 2 months ago #143258 by rodw

Replied by rodw on topic Writing a needet HAL Component

Actually, here is version 2. Couple of other issues I noticed.

This bit should only run once and solves the static variable initialisation

Code:

if(first_pass){
		//set up
		counter = from;
		first_pass = 0;
	}

This bit is just to protect from a 0 or negative value for cycle

Code:

	if(cycle < 1){
		cycle = 1;
	}

This bit sets the direction to count

Code:

			if(from > to)		// Set the direction to count 
				step = -1;
			else
				step = 1;

So if warping, you want to count backwards to the start again so we need to set a flag and invert step direction

Code:

				if(warp){
					is_warping = 1;
					if(step > 0)
						step = -1;
					else
						step = 0;
				}

So if we are counting back to to and we get there, we need to invert the step direction and say we are going in the normal direction

Code:

		else{
			counter += step;
			if(counter == to){
				is_warping = 0;
					if(step > 0)
						step = -1;
					else
						step = 0;				
			}

The only thing I will say is the test to get to from and to are not very robust becasue if something goes wrong, it will keep counting forever. it is probably safer to use <= and >= in the if statements which is more defensive.

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rodw
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7 years 2 months ago #143259 by rodw

Replied by rodw on topic Writing a needet HAL Component

Speaking of being defensive

Code:

				counter = to;	// stop counting

This probably should be:

Code:

				counter = to-1;	// stop counting

That way on the next pass, counter will increment by 1 and it will be equal to to again

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Emanresu
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7 years 2 months ago #143263 by Emanresu

Replied by Emanresu on topic Writing a needet HAL Component

OK, same result.

i have to change:

Code:

	if(cycle < 1){
		cycle = 1;

Code:

if(cycle < 1){
		cycle == 1;

or i get the Error:
51:9: error: lvalue required as left operand of assignment

after changing it, it says:
value computed is not used

in 56:3: it says:
error expected ´;´ before ´this_cycle´

i changed it to:
;this_cycle = 0;

But its the only ; "infront" of something in the code ?!

Last thing is 85:1:
error: expected identifier or ´(´before ´}´ token

error is gone if i delete the last }

This is exciting

Time after time with a lot of Google some little parts give me an Idea, what they are doing.

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