Problems with I2C/PSOC5 LP and Digital Pot MCM4661

[JoLo_285951]

Dear All:

I am working with a design requiring a digital potentiometer, in this case the MCP4661 from Microchip.  Please find attached datasheet of this chip.

To test the potentiometer, I am using CY8CKIT-050 and the Evaluation kit of the potentiometer. See attached, the User Guide of the Evaluation kit of MCP4661 and a photo of the assembly I am using to test it.

I just want to write and read from register of the MCP4661. Write, to set the resistor and read to know the actual value.

I have developed two functions (see attached project) to write and read:

void mcpWrite(uint8 chipAddress, uint8 Register, uint8 Value);

uint16 mcpRead(uint8 chipAddress, uint8 Register);

I have a problem on both functions. When I write with I2CM_MasterWriteBuf, and then, wait until transfer complete with (see line 77, on MCP4661_I2C.c):

if (0u != (I2CM_MasterStatus() & I2CM_MSTAT_WR_CMPLT)),

It never ends, stay in this loop forever.

On the other hand, I2CM_MasterWriteBuf, return I2C_MSTR_NOT_READY

Can anyone give a hand and tell me why I am no able to communicate with MCP4661? Any idea? Any comment will be welcome.

Please find attached also the Evaluation kit schematic that I am using (hand-drawn). The kit is populated with MCP4661 by default, that I want to use.

Attached also the project I am using to test it.

Thanks in adavance,

Joaquin.

[MotooTanaka · Accepted solution]

Hi,

I've just briefly saw your main.c.

I would recommend you to call

  I2CM_Start() ;

just after

CyGlobalIntEnable ;

===================

int main(void)

{

    uint16 temp;

     /* The LCD will help us to debug application */

    LCD_Char_Start();

    LCD_Char_PrintString("Test MCP46461");

    CyGlobalIntEnable; /* Enable global interrupts. */

    I2CM_Start() ;

    /* Place your initialization/startup code here (e.g. MyInst_Start()) */

    temp= mcpRead(mcpEVK, VW1);

    LCD_Char_Position(1,0);

    LCD_Char_PrintInt16(temp);

    //mcpWrite(mcpEVK, VW1, 0);

    //mcpWrite(mcpEVK, VW0, 0);

    for(;;)

    {

        /* Place your application code here. */

    }

}

===================

moto

[MotooTanaka]

Hi,

I also put CY8CKIT-059 sample of using I2C with LM75B in the discussion

CY8CKIT-059 I2C pins P12_0 and P12_1

I hope this could be a hint of using I2C with PSoC 5LP.

moto

[JoLo_285951]

Hello Motoo Tanaka,

Thank you for your support.

You are right, I forgot to add I2CM_Start() ;

Sorry you lose you time...ohhhhhhhh! I couldnt see the problem after one day and half working with this!!!

Thanks again.

Joaquin.