event.com problem. Not detecting "term" parameter

[alioth]

Hi.

I am trying to interface Arduino with p3dv4 

Sending data from lua script to Arduino is fine. And no problem receiving data in arduino side.

To read data coming from arduino in lua script, I really like the event.com concept. It makes (or should) things easy.

The idea is to isolate a string between '/n' or whatever character, so I can manage a string as a complete comand.

The comands I send from arduino have the format "A=xxxxx/n", and I have manage to isolate the key 'A' and the number xxxxx 

But I having problems to isolate the "A=xxxxx" and not being mixed with the command before or behind.

This is an example code:

Quote

function Arduino_Data(Arduino_Com_Port, strng, length)

    ipc.display (strng)

    if string.match(strng, "=") then                --codes with '=' inside, isolate the key (before the '= ')and value (behind =), then send de command with the value.

        local key = string.match(strng, "^.-=")
        key = string.sub(key, 1, -2)                     --now the key is isolated

        local value = string.match(strng, "=.*$")
        value = tonumber(string.match(value, "[^=%s].*"))    --number isolate

  
        if string.match(key, "A") then 
            ipc.control(65716, value)
        end
    

    else                                             -- codes without =, direct command

    -- if string.match(strng, "A23") then ...
    -- if string.match(strng, "F14") then ...

    end
   
    
end  -- function end

event.com(Arduino_Com_Port, 12, 2 , '/n' , "Arduino_Data")

I am sending the data from arduino every 500 milisecs. Quite slow, to be sure no problems with buffers.. (I think).

I have test '/n',  13, even other characters like 'X', space. But the string comes truncated. I see it with  ipc.display (strng) 

Only works  if using   

Quote

event.com(Arduino_Com_Port, 12, 9 , '/n' , "Arduino_Data")

 I don't know the reason.  Is '/n'  two bytes and then total lenght is 9 perhaps..?

With the 9, I see in the ipc.display window a blank line, and in the next line the complete code. So, it works in this way.  I can use this method if always sending the same commands lenght...

But I would like to use diferent string lengths with "term" parameter working.

What I am doing wrong? 😕

 

thanks in advance

Arturo.

 

Edited October 13, 2018 by alioth

[Pete Dowson]

On 10/13/2018 at 10:51 AM, alioth said:

 I don't know the reason.  Is '/n'  two bytes and then total lenght is 9 perhaps..?

Yes, '\n' is two characters: '/' and 'n'.  A new line is '\n'. You are using the wrong Escape character. All of the special characters use \,. For a single \ you need \\.

Pete

 

[alioth]

Thanks for the answer and sorry for my mistake 😕  (oh my god).

But, I have problems yet.

I have installed a serial monitor software, as you suggested in some thread (Now I dont know how I was living without it).

The bytes sent from Arduino in a typical command is something like this:

41 3D 30 30 30 37 39 0D 0A                         A=00079..
So, the "\n" are the  0x0D + 0x0A bytes.

With this command format, if I use  

Quote

event.com(Arduino_Com_Port, 9 , 9 ,0x0A, "Arduino_Data") 

it works fine all the time.

But, If I use 

Quote

event.com(Arduino_Com_Port, 16 , 4 ,0x0A, "Arduino_Data") 

As I know, it should work the same way. And It works most of the time.

But something like 1/100 I receive a diferent format string and my functions fails to isolate the key and the value.

Can be related to event.com function?   With " 9 , 9" works always fine..

Thanks.

 

EDIT:

I have looged the string received from event.com and I get this:

Quote

3822250 LUA.0: A=00260

  3822359 LUA.0: A=00262

  3822453 LUA.0: A=00263

  3822484 LUA.0: B=00029

  3822578 LUA.0: A=00265

  3822781 LUA.0: A=00266

  3822984 LUA.0: A=00265

  3823093 LUA.0: A=00263

  3823203 LUA.0: A=00
  3823218 LUA.0: 261

  3823297 LUA.0: A=00259
  3823422 LUA.0: 
  3823453 LUA.0: A=00256

  3823531 LUA.0: A=00255

  3823547 LUA.0: B=00028

 

 

 

 

Edited October 22, 2018 by alioth

[Pete Dowson]

1 hour ago, alioth said:

But something like 1/100 I receive a diferent format string and my functions fails to isolate the key and the value.

By having a miimum of 4 acceptable, if there is a delay after 4 characters are received then you will get what has already arrived. The delay may be from the Arduino end, or it could be a higher priority action happening in the PC. Altough I do set the comms input at high priority, it isn't at "critical" level, which would be needed to have exclusive use of a processor core for that thread, but not warranted and problematic.

1 hour ago, alioth said:

Can be related to event.com function?   With " 9 , 9" works always fine..

So why not use that? Fixed length messages are bound to be more reliable and easier to handle.

 3823203 LUA.0: A=00
 3823218 LUA.0: 261

This illustrates what I said. 4 characters arrived but there was a delay before the "261" part.

3823297 LUA.0: A=00259
  3823422 LUA.0: 

Here the delay was before the terminator you otherwise wait for.

In any case, shouldn't you be discarding invalid input?

Pete

 

[alioth]

 

1 hour ago, Pete Dowson said:

So why not use that? Fixed length messages are bound to be more reliable and easier to handle.

This was my thought, but I wanted to understand what was happening. Now is perfectly clear. 

I will use fixed length, and I now understand the needed of some line discarding invalid inputs. Even with fixed length I supose it is a good idea.

 

Thank you so much.

Arturo.