I2Cm Fault Tolerance

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ETRO_SSN583
Level 9
Level 9
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I am using an application with a simple master (PSOC) and a slave device.

   

 

   

When I issue R/W commands to Slave, I accumulate the return values from the I2C API,

   

and then evaluate this for > 0 (errors), eg. looking for an error, to implement error handling.

   

 

   

If I disconnect clock or data line the I2Cm gets stuck in a I2Cm API, a function called clockstretch2.

   

 

   

So net effect is to take down entire application.

   

 

   

Code being used -

   

 

   

 unsigned char I2Cok = 0;

   


 I2Cok = ( I2Cm_fSendStart( SLAVADD, I2Cm_WRITE ) == 0 ) ? 1 : 0;   // Send start bit
 I2Cok = ( I2Cm_fWrite( memadr ) == 0 ) ? I2Cok + 1 : I2Cok;                 // Send command to read Tobject
 I2Cok = ( I2Cm_fSendRepeatStart( SLAVADD, I2Cm_READ ) == 0 ) ? I2Cok + 1 : I2Cok; // Send repeat start bit
 rxBuf[ 0 ] = I2Cm_bRead( I2Cm_ACKslave );      // Read low order byte
 rxBuf[ 1 ] = I2Cm_bRead( I2Cm_ACKslave );      // Read high order byte
 rxBuf[ 2 ] = I2Cm_bRead( I2Cm_ACKslave );      // Read PEC

   

 

   

Code works fine, until I disconnect a clock or data line to I2C slave, or if a loss of power to slave

   

occured. Clearly this should be considered a defect in I2C API implementation, inability to handle

   

a HW failure. I suppose a workaround would be watchdog, but that I think is a poor choice.

   

 

   

Is this also case for Creator ?

   

 

   

Regards, Dana.

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