Any example code for I2C

Sawmiller · 2013-06-02 12:42

do we have any example code for I2C ? in C for the prop that is.
i am looking at i2c.h in propgcc/propeller-elf/include and see the briefs... but i could use a lil more if someone know of some code.
dan

dgately · 2013-06-02 17:58

Sawmiller wrote: »

do we have any example code for I2C ? in C for the prop that is.
i am looking at i2c.h in propgcc/propeller-elf/include and see the briefs... but i could use a lil more if someone know of some code.
dan

Here's a Spin2Cpp-created project for the Wii Nunchuk that uses i2c. Hopefully, you'll be able to mod as needed. This is a Zip of a SimpleIDE project.

TestWiNunchukC.zip

dgately

Sawmiller · 2013-06-02 18:06

thnaks, will look at it.
dan

David Betz · 2013-06-02 19:35

Sawmiller wrote: »

do we have any example code for I2C ? in C for the prop that is.
i am looking at i2c.h in propgcc/propeller-elf/include and see the briefs... but i could use a lil more if someone know of some code.
dan

Did you try using the functions mentioned in i2c.h? Did you have problems with them that caused you to look for other solutions?

Sawmiller · 2013-06-03 03:36

hi David,
i was looking for example code because i have written the functions as i think they need to be, foe example
i2c_Address = simple_i2cOpen( DS1721_Addr,i2cSCL,i2cSDA); // get a i2c address for the ds1721 chip

flag = i2cWrite(i2c_Address,DS1721_Addr,AccessConfig,8,False); // tell DS1721 we are going to config

if (flag == 0)
printf("Success on config \n");

if (flag == -1)
printf("Failure on config\n");
pause (1000);
flag = 2;

flag = i2cWrite(i2c_Address,DS1721_Addr,Cont_09_Bit,8,True); // tell DS1721 9 bit accuracy
if (flag == 0)
printf("Success on 9 bit\n");

pause (1000);
flag = 2;

flag = i2cWrite(i2c_Address,DS1721_Addr,StartConvert,8,False);
if (flag == 0)
printf("success on starting conversion of temp\n");

and i am getting success printf's ( flag coming back as zero )
but i am not getting a valid temp reading, have gone over my wiring several times
( using a setup that i put together in 2008 and used spin with.)

i am excited about being able to use C with the prop, but was hoping for more documentation like the prop manual ( which is a lil more wordy ) or like the way they did the sx when they were programming that.
coming back to programming after a 5 year hiatus so i am a lil rusty.
spin2cpp appears to work, but doesn't interact with the library
sorry, don't mean to be so verbose.
dan

David Betz · 2013-06-03 06:51

Sawmiller wrote: »

hi David,
i was looking for example code because i have written the functions as i think they need to be, foe example
i2c_Address = simple_i2cOpen( DS1721_Addr,i2cSCL,i2cSDA); // get a i2c address for the ds1721 chip

flag = i2cWrite(i2c_Address,DS1721_Addr,AccessConfig,8,False); // tell DS1721 we are going to config

if (flag == 0)
printf("Success on config \n");

if (flag == -1)
printf("Failure on config\n");
pause (1000);
flag = 2;

flag = i2cWrite(i2c_Address,DS1721_Addr,Cont_09_Bit,8,True); // tell DS1721 9 bit accuracy
if (flag == 0)
printf("Success on 9 bit\n");

pause (1000);
flag = 2;

flag = i2cWrite(i2c_Address,DS1721_Addr,StartConvert,8,False);
if (flag == 0)
printf("success on starting conversion of temp\n");

and i am getting success printf's ( flag coming back as zero )
but i am not getting a valid temp reading, have gone over my wiring several times
( using a setup that i put together in 2008 and used spin with.)

i am excited about being able to use C with the prop, but was hoping for more documentation like the prop manual ( which is a lil more wordy ) or like the way they did the sx when they were programming that.
coming back to programming after a 5 year hiatus so i am a lil rusty.
spin2cpp appears to work, but doesn't interact with the library
sorry, don't mean to be so verbose.
dan

If you could post all of your code I could try running it to see where it is getting into trouble. In the meantime, I'm attaching the source code for the simple i2c driver in the hopes that that might help you.

i2c_simple.c

Sawmiller · 2013-06-03 08:53

thanks.
if you have time, please look.
this is the latest itteration, was trying simple open, so i didnt have to figure out cog driver yet, but i commented out simple and am playing with the cog driver

David Betz · 2013-06-03 09:06

Sawmiller wrote: »

thanks.
if you have time, please look.
this is the latest itteration, was trying simple open, so i didnt have to figure out cog driver yet, but i commented out simple and am playing with the cog driver

I can see a number of problems right away. First, you should not redefine I2C_COGDRIVER. It is already defined in i2c.h and redefining it is likely to cause problems. Second, you need to pass the address of a I2C_COGDRIVER structure to i2cOpen. You're passing an uninitialized pointer. Try modifying your code like this:

int main()                                    // Main function
{
  long freq          = 100000 ;     
  int  i2cSDA        = 5;                     // pin 5
  int  i2cSCL        = 3;                     // pin 3
  int DS1721_Addr      = 146;                 // ds1721 address 10010010
  int DS1721_Addr_Read = 147;                 // ds1721 address +1 for read

  int ReadTemp      = 0xAA;
  int AccessTH      = 0xA1;
  int AccessTL      = 0xA2;
  int AccessConfig  = 0xAC;
  int ReadCounter   = 0xA8;
  int ReadScope     = 0xA9;
  int StartConvert  = 0x51;
  int StopConvert   = 0x22;
  int OneShotMode   = 1;
  int Cont_09_Bit   = 0x00; 
  
  //I2C_SIMPLE *  i2c_Address;
  I2C *  i2c_Address;
    int cog = 3;

  I2C_COGDRIVER COG;
 
  int flag = 2;
  int tempvar = 0;
  const int  True  = 1;
  const int False = 0;

  pause (1000);


    printf("starting\n");

    // simple_i2cOpen( i2c_Address,i2cSCL,i2cSDA);     // get a i2c address for the ds1721 chip

      i2c_Address = i2cOpen(&COG, i2cSCL, i2cSDA, freq);

Sawmiller · 2013-06-03 09:31

ok, thanks david. will let this settle for a while
where did you find i2c_simple.c ?

am trying to see why I2C_COGDRIVER COG; works
but if i uncomment I2C_SIMPLE i2c_Address; it doesnt work the same.
sigh
thanks for the help, i will work on this some more, and see if i can't dragg my head out of where it is

David Betz · 2013-06-03 09:45

Sawmiller wrote: »

ok, thanks david. will let this settle for a while
where did you find i2c_simple.c ?

am trying to see why I2C_COGDRIVER COG; works
but if i uncomment I2C_SIMPLE i2c_Address; it doesnt work the same.
sigh
thanks for the help, i will work on this some more, and see if i can't dragg my head out of where it is

i2c_simple.c is part of the PropGCC source code on Google Code:

http://code.google.com/p/propgcc/

It's in propgcc/lib/sys/propeller.

Sawmiller · 2013-06-04 18:38

This works now, will add display,probally beans old hc4 LEDs and control over a 120v outlet later.
But for now its working.
Thanks David.

David Betz · 2013-06-04 20:43

Sawmiller wrote: »

This works now, will add display,probally beans old hc4 LEDs and control over a 120v outlet later.
But for now its working.
Thanks David.

Congratulations on getting it working! By the way, someone else has discovered a problem with using the i2c driver in xmm modes. I'm working on a fix but I wanted to warn you in case you decide to switch to xmm at some point.

Any example code for I2C

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