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TMS320F28022: Is there a good example using the I2C that doesn't use interrupts?

Cool Javelin
Expert 1680 points

Part Number: TMS320F28022
Other Parts Discussed in Thread: CONTROLSUITE

I have been beating my head on the I2c in the 28022 (Piccolo) for a few days, and still haven't gotten it.

I have tried to review the code in the controlSUITE under device_support\f2802x\v230\f2802x_examples_structs\i2c_eeprom.

While I have some question on THAT code (separate thread), it uses interrupts to service the various events. I can follow the interrupt logic, but it is overly complex.


Is there an example to demonstrate usage of the Piccolo I2C using polling rather then interrupts?

Thanks,

Mark

  • 0
    Guru 192875 points

    Hi Mark,

    Refer to this example:

    Fullscreen 1057.5126.I2C_Writing_Reading_EEPROM.txt Download 
    //////////////////////////
// Write data to EEPROM //
//////////////////////////
//I2C_SLAVE_ADDR = 0x50 address of the EEPROM
//I am writing 'h','e','l','l','o' to the EEPROM and then read it back later
//I2C_NUMBYTES = 5
//[MemoryHighAddr:MemoryLowAddr] -Address within the eeprom where you want to read/write
//Data[] has the word 'hello' and RxdData[] will store data read from the eeprom
   I2caRegs.I2CSAR = I2C_SLAVE_ADDR; 			//Set slave address
   I2caRegs.I2CCNT = I2C_NUMBYTES + 2; 			//Set count to 5 characters plus 2 address bytes
   I2caRegs.I2CDXR = MemoryHighAddr;			//Send eeprom high address            
   I2caRegs.I2CMDR.bit.TRX = 1; 				//Set to Transmit mode
   I2caRegs.I2CMDR.bit.MST = 1; 				//Set to Master mode
   I2caRegs.I2CMDR.bit.FREE = 1;				//Run in FREE mode
   I2caRegs.I2CMDR.bit.STP = 1; 				//Stop when internal counter becomes 0
   I2caRegs.I2CMDR.bit.STT = 1; 				//Send the start bit, transmission will follow
   while(I2caRegs.I2CSTR.bit.XRDY == 0){}; 		//Do nothing till data is shifted out
   I2caRegs.I2CDXR = MemoryLowAddr;  			//Send eeprom low address
   
   for(i = 0; i < I2C_NUMBYTES; i++){
   	while(I2caRegs.I2CSTR.bit.XRDY == 0){}; 	//Do nothing till data is shifted out
   	I2caRegs.I2CDXR = Data[i]; 					//Send out the message
   } 
//////////////////////////
// Read data from EEPROM//
//////////////////////////
   I2caRegs.I2CSAR = I2C_SLAVE_ADDR; 			//Set slave address
   I2caRegs.I2CCNT = 2; 						//Set count to 2 address bytes
   I2caRegs.I2CDXR = MemoryHighAddr;			//Send eeprom high address            
   I2caRegs.I2CMDR.bit.TRX = 1; 				//Set to Transmit mode
   I2caRegs.I2CMDR.bit.MST = 1; 				//Set to Master mode
   I2caRegs.I2CMDR.bit.FREE = 1;				//Run in FREE mode
   I2caRegs.I2CMDR.bit.STP = 0; 				//Dont release the bus after Tx
   I2caRegs.I2CMDR.bit.STT = 1; 				//Send the start bit, transmission will follow
   
   while(I2caRegs.I2CSTR.bit.XRDY == 0){}; 		//Do nothing till data is shifted out
   I2caRegs.I2CDXR = MemoryLowAddr; 			//Send eeprom low address
   I2caRegs.I2CCNT = I2C_NUMBYTES;				//read 5 bytes from eeprom
   I2caRegs.I2CMDR.bit.TRX = 0; 				//Set to Recieve mode
   I2caRegs.I2CMDR.bit.MST = 1; 				//Set to Master mode
   I2caRegs.I2CMDR.bit.FREE = 1;				//Run in FREE mode
   I2caRegs.I2CMDR.bit.STP = 1; 				//Stop when internal counter becomes 0
   I2caRegs.I2CMDR.bit.STT = 1; //Repeated start, Reception will follow
   for(i = 0; i < I2C_NUMBYTES; i++){
   	while(I2caRegs.I2CSTR.bit.RRDY == 0){}; 	//I2CDRR not ready to read?
   	RxdData[i] = I2caRegs.I2CDRR;
   }

    Regards,

    Gautam