Platform eXtended Library (PXL) to AVR, howto I2C

[pascalbythree]

Afther your help at this forum, i want to I2C from my Raspberry to my AVR. Using Asphyre PXL. Can anybody help me out how to use this function ? Need to convert a buffer pointer and buffersize to a Incomming String variable. Because i can not work on pointers myself.

PXL.Boards.RPi.pas

Code: Pascal  [Select][+][-]

1. function TFastSPI.Read(const Buffer: Pointer; const BufferSize: Cardinal): Cardinal;
2. begin
3.   Result := Transfer(Buffer, nil, BufferSize);
4. end;
5.  

Own code:

Code: Pascal  [Select][+][-]

1. constructor TApplication.Create;
2. begin
3.   FSystemCore := TFastSystemCore.Create;
4.   FGPIO := TFastGPIO.Create(FSystemCore);
5.   FDataPort := TFastI2C.Create(FGPIO);
6.  
7.   // I2C Write and slave commands
8.  
9. end;

Please help... Greets, Wouter

[Dzandaa]

Hi,

I don't know if it is you are waiting for (or even if this is working):

Code: Pascal  [Select][+][-]

1.  Str := '';
2.  SetString(Str, PChar( Buffer), BufferSize);  
3.  

B->

[pascalbythree]

I forgot about Github: rpiplc_pas/native/examples/i2c_write_test.lpr

Code: Pascal  [Select][+][-]

1. program i2c_write_test;
2.  
3. uses
4.   sysutils, i2c;
5.  
6. var
7.   i2cMaster: TI2cMaster;
8.   startAddr: uint16 = $38;
9.   data: TBytes;
10.   i: integer;
11.   S:String;
12.  
13. begin
14.   S := 'Hello World!                   ';
15.  
16.   i2cMaster := TI2cMaster.Create;
17.  
18.   if not i2cMaster.Initialize(i2c_1) then
19.   begin
20.     WriteLn('Error opening i2c device i2c_1');
21.     i2cMaster.Free;
22.     Halt(1);
23.   end;
24.    
25.   if i2cMaster.WriteBytes(byte(startAddr), @data[0], Length(data)) then
26.   begin    
27.     WriteLn('Success: WriteBytes');
28.   end
29.   else
30.     WriteLn('Error: WriteBytes');
31.  
32.   i2cMaster.Free;
33. end.

Can somebody help me out changing this code to write the S string through $38 ? Or loop and write a byte ?

Code: Pascal  [Select][+][-]

1. i2cMaster.WriteBytes(byte(startAddr), @data[0], Length(data))

in the Unit i2c.pas

Code: Pascal  [Select][+][-]

1. function WriteBytes(address: byte; const data: PByte; size: byte): boolean;

[cdbc]

Hi
I think you should be able to do this:

Code: Pascal  [Select][+][-]

1. if i2cMaster.WriteBytes(byte(startAddr), @S[1], Length(S)) then

Regards Benny

[pascalbythree]

Yay ! Again in a lucky day!

From PXL on my RPI to FPC on my AVR works fine!


Now i am going to try from AVR to FPC

You all will hear back from me soon!

[pascalbythree]

I'm Back!

Code: Pascal  [Select][+][-]

1. Read(const Buffer: Pointer; const BufferSize: Cardinal): Cardinal;

Anybody got a snip to receive values on the RPI from the AVR as Master ?

[cdbc]

Hi
Dunno, if you want bytes or string?!? But:

Code: Pascal  [Select][+][-]

1. // string first
2. var
3.   Res: cardinal;
4.   S: string;
5. begin {Read(const Buffer: Pointer; const BufferSize: Cardinal): Cardinal;}
6.   setlength(S,1024);
7.   Res:= Read(@S[1],length(S));
8.   setlength(S,Res);
9.   ...
10. end;
11. // or bytes
12. var
13.   Res: cardinal;
14.   B: TBytes;
15. begin
16.   setlength(B,1024);
17.   Res:= Read(@B[0],length(B));
18.   setlength(B,Res);
19.   ...
20. end;
21.  

I think that should do the trick... 
Regards Benny

[pascalbythree]

Benny? It does not seem to connect.

Can you see what i did wrong ?

Grtz...Wouter


AVR side:

Code: Pascal  [Select][+][-]

1. program WVW_AVR_SDIE;
2.  
3. uses
4.   uart, i2c, delay, simplemath;
5.  
6. var
7.   i2c_master: TI2CMaster;
8.   S:String;
9.   i, value:byte;
10.   counter:integer;
11.  
12. const
13.   BAUD_Rate = 115200;
14.   BAUD_SETTING = (((F_CPU + 4*BAUD_Rate) shr 3) div BAUD_Rate) - 1;
15.  
16.   //****************************************************************************************************************
17.     function IntToStr(const i: Integer): string;
18.     begin
19.      Str(i, Result);
20.     end;
21.      
22.     function StrToInt(const s: string): Integer;
23.     var
24.      code: Integer;
25.     begin
26.      Val(s, Result, code);
27.     end;
28. //****************************************************************************************************************     
29.        
30.  
31. begin
32.   uart_init1(115200,true);  
33.   i2c_master.init(I2C_50kHz);
34.  
35.   uart_transmit('Starting up...'#13);
36.  
37.   S := 'Hello World!';
38.  
39.   i2c_master.start($18, false); //shl 1;
40.  
41.   counter := 1;
42.   repeat    
43.     counter := counter + 1;
44.         if counter = 254 then counter := 1;
45.     uart_transmit('Counter='+IntToStr(counter)+#10+#13);
46.                
47.         for i:=1 to length(S)-1 do
48.     begin
49.             value := ord(S[i]);
50.         i2c_master.WriteByte(value);
51.             delay_ms(2);       
52.         end;   
53.        
54.         i2c_master.WriteByte(Ord(#10));
55.         i2c_master.WriteByte(Ord(#13));
56.  
57.         delay_ms(2);   
58.   until 1=2;  
59.   i2c_master.stop;
60. end.

RPI Side:

Code: Pascal  [Select][+][-]

1. program WVW_RPI_SIDE;
2.  
3. uses
4.   SysUtils, PXL.TypeDef, PXL.Boards.Types, PXL.Sysfs.UART, PXL.Boards.RPi, crt;
5.  
6. var    
7.   SystemCore: TFastSystemCore;
8.   GPIO: TFastGPIO;
9.   PortI2C: TFastI2C;
10.   AddrI2c: Byte; // Address of the component
11.   counter: byte;
12.      
13.   Res: cardinal;
14.   S: string;
15.   B: TBytes;
16.  
17. begin
18.   SystemCore:= TFastSystemCore.Create;
19.   GPIO:= TFastGPIO.Create(SystemCore);
20.   PortI2C:= TFastI2C.Create(GPIO);
21.   AddrI2c:= $18; // Address of my test component
22.   PortI2C.SetAddress(AddrI2C);
23.  
24.   counter := 0;
25.   repeat
26.      counter := counter + 1;
27.          if counter = 255 then counter := 1;
28.          writeln('counter='+IntToStr(counter));
29.  
30.      setlength(S,1024);
31.      Res := PortI2C.Read(@S[1],length(S));
32.      setlength(S,Res);
33.  
34.      writeln('Res=' + IntToStr(res));
35.      writeln('S[1]='   + S[1]);                  
36.          writeln('S='   + S);            
37.                        
38.          delay(55);
39.   until keypressed;      
40.  
41.   PortI2C.Free;
42.   GPIO.Free;
43.   SystemCore.Free;  
44. end.

[DonAlfredo]

I guess you are using two I2C-masters. And that will never work.
So, the question is: why do you use a I2C-master on the AVR ?

[cdbc]

Hi
What DonAlfredo says, he beat me to it and probably knows way more about this than I do 
Hmmm, it seems, on one side of the connection you're writing a lump of bytes using:

i2c_master.WriteByte(value);

followed by a CrLf pair, over and over again.
Then on the other side of the connection, you're reading a "string" in one fell swoop?!? It seems to me, that at least you should send and receive the same datatype... Also have you checked, that you can e.g.: send 1 BYTE +crlf and receive 1 BYTE +crlf successfully? Then after this, is it a must, that you send the bytes separate, because your 'read' seems to accept a @buffer --> ? to 1 or more bytes ?
Too many unknowns, for me to figure out, you should have another look at the documentation for your kit.
Regards Benny

[pascalbythree]

Maybe somebody can help me at this URL ?

https://forum.lazarus.freepascal.org/index.php/topic,65994.0.html

[DonAlfredo]

Again. Make the AVR the slave. This will solve all your issues and will make the RPi a simple polling device instead of something that requires threads to be able to respond to data.