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LAUNCHXL-F28069M: I2C, TX FIFO, no RX and no interrupt on F280xx

Lotfi BAGHLI
Intellectual 860 points
Part Number: LAUNCHXL-F28069M
Other Parts Discussed in Thread: C2000WARE

Hi

I want to configure the I2C to use no interrupt but the TX FIFO in master mode only

I need only Tx as a master, no reading (Rx). It is to control an OLED screen SSD1306

After many searches and examples I managed to have this config

The configuration

//-----------------------------------------------------------------------------
// InitI2C - This function initializes the I2C to a known state.
void InitI2C()
{
    // Initialize I2C-A
   I2caRegs.I2CMDR.all = 0x0000;
   I2caRegs.I2CSAR = I2C_SLAVE_ADDR;		// Slave address
   // 90 MHz/( (8+1)(10+5 + 5+5)) = 400 kHz
   I2caRegs.I2CPSC.all = 8;		    		// Prescaler - need 7-12 Mhz on module clk
   I2caRegs.I2CCLKL = 10;					// NOTE: must be non zero
   I2caRegs.I2CCLKH = 5;					// NOTE: must be non zero

   //I2caRegs.I2CIER.all = 0x24;			// Enable SCD & ARDY interrupts  0010 0100
   I2caRegs.I2CIER.all = 0x00;				// No interrupt
//   I2caRegs.I2CIER.bit.AAS = 0;				// Addressed as slave interrupt enable bit
//   I2caRegs.I2CIER.bit.SCD = 1;				// Stop condition detected interrupt enable bit
//   I2caRegs.I2CIER.bit.XRDY = 0;			// Transmit-data-ready interrupt enable bit
//   I2caRegs.I2CIER.bit.RRDY = 0;			// Receive-data-ready interrupt enable bit
//   I2caRegs.I2CIER.bit.ARDY = 1;			// Register-access-ready interrupt enable bit
//   I2caRegs.I2CIER.bit.NACK = 0;			// No-acknowledgment interrupt enable bit
//   I2caRegs.I2CIER.bit.ARBL = 0;			// Arbitration-lost interrupt enable bit

   //I2caRegs.I2CFFTX.all = 0x6000;			// Enable FIFO mode and TXFIFO
   I2caRegs.I2CFFTX.bit.I2CFFEN = 1;		// Enable the I2C FIFO mode
   I2caRegs.I2CFFTX.bit.TXFFRST = 1;		// Enable the transmit FIFO operation
   I2caRegs.I2CFFTX.bit.TXFFINTCLR = 0;		// Clear the TXFFINT flag
   I2caRegs.I2CFFTX.bit.TXFFIENA = 0;		// TXFFINT flag does not generate an interrupt when set
   I2caRegs.I2CFFTX.bit.TXFFIL = 0;			// Transmit FIFO interrupt level

   //I2caRegs.I2CFFRX.all = 0x0000;			// No RXFIFO, no clear RXFFINT
   I2caRegs.I2CFFRX.bit.RXFFRST = 0;		// **Disable** the receive FIFO operation
   I2caRegs.I2CFFRX.bit.RXFFINTCLR = 0;		// Clear the RXFFINT flag
   I2caRegs.I2CFFRX.bit.RXFFIENA = 0;		// RXFFINT flag does generate an interrupt when set
   I2caRegs.I2CFFRX.bit.RXFFIL = 0;			// Receive FIFO interrupt level

   //I2caRegs.I2CMDR.all = 0x0020;			// Take I2C out of reset,Stop I2C when suspended
   I2caRegs.I2CMDR.bit.NACKMOD = 0;			// NACK mode bit
   I2caRegs.I2CMDR.bit.FREE = 0;			// Stop I2C when suspended
   I2caRegs.I2CMDR.bit.STT = 0;				// START condition bit
   I2caRegs.I2CMDR.bit.STP = 0;				// STOP condition bit
   I2caRegs.I2CMDR.bit.MST = 0;				// Slave mode
   I2caRegs.I2CMDR.bit.TRX = 0;				// Receiver mode
   I2caRegs.I2CMDR.bit.XA = 0;				// 7-bit addressing mode
   I2caRegs.I2CMDR.bit.RM = 0;				// Nonrepeat mode
   I2caRegs.I2CMDR.bit.DLB = 0;				// Digital loopback mode is disabled
   I2caRegs.I2CMDR.bit.IRS = 1;				// The I2C module is enabled
   I2caRegs.I2CMDR.bit.STB = 0;				// The I2C module is not in the START byte mode
   I2caRegs.I2CMDR.bit.FDF = 0;				// Free data format mode is disabled
   I2caRegs.I2CMDR.bit.BC = 0;				// 8 bits per data byte

    oledInit();
	oledClear();
	oledGotoYX( 0, 0 );
	oledPrint( "PWM" );
}
//-----------------------------------------------------------------------------
int16_t i2c1Xfer(
	Uint8 address,
	Uint8* wdata, int wsize,
	Uint8* rdata, int rsize )
{
Uint16 i;

//	I2caRegs.I2CMDR.bit.IRS = 1;

//	// Make sure I2C is not busy and has stopped
//	while (I2caRegs.I2CSTR.bit.BB == 1);		// busy loop
//	I2caRegs.I2CSTR.bit.SCD = 1;				// Clear the SCD bit (stop condition bit)
//	while(I2caRegs.I2CMDR.bit.STP == 1);		// stop bit loop

	I2caRegs.I2CSAR = address;           			// I2C slave address
//	while (I2caRegs.I2CSTR.bit.BB == 1);		// still busy?

    I2caRegs.I2CCNT = wsize;					// Setup number of bytes to send


	for (i=0; i<wsize; i++)
		{
//		usDelay(1);
		I2caRegs.I2CDXR = *(wdata+i);
		}
	I2caRegs.I2CMDR.all = 0x6E20; 				// Send the TX FIFO :   0110 1110 0010 0000
//	I2caRegs.I2CMDR.all = 0x6620; 				// STT=1 :   0111 0110 0010 0000

	//	I2caRegs.I2CMDR.bit.NACKMOD = 0;			// NACK mode bit
	//	I2caRegs.I2CMDR.bit.FREE = 1;				// Run free I2C when suspended
	//	I2caRegs.I2CMDR.bit.STT = 1;				// START condition bit
	//	I2caRegs.I2CMDR.bit.STP = 1;				// STOP condition bit
	//	I2caRegs.I2CMDR.bit.MST = 1;				// Master mode
	//	I2caRegs.I2CMDR.bit.TRX = 1;				// Transmitter mode
	//	I2caRegs.I2CMDR.bit.XA = 0;					// 7-bit addressing mode
	//	I2caRegs.I2CMDR.bit.RM = 0;					// Nonrepeat mode
	//	I2caRegs.I2CMDR.bit.DLB = 0;				// Digital loopback mode is disabled
	//	I2caRegs.I2CMDR.bit.IRS = 1;				// The I2C module is enabled
	//	I2caRegs.I2CMDR.bit.STB = 0;				// The I2C module is not in the START byte mode
	//	I2caRegs.I2CMDR.bit.FDF = 0;				// Free data format mode is disabled
	//	I2caRegs.I2CMDR.bit.BC = 0;					// 8 bits per data byte

//	I2caRegs.I2CMDR.bit.STP = 1;  				// stop bit when CNT=0
//	usDelay(1);
//  while(!I2caRegs.I2CSTR.bit.SCD);       	// wait for STOP condition

	return I2C_SUCCESS;
}
//-----------------------------------------------------------------------------
void oledCommand( Uint8 ch )
{
    Uint8 bytes[2];
    bytes[0] = SSD1308_Command_Mode;
    bytes[1] = ch;
    i2c1Xfer( SSD1308_Address, bytes, 2, NULL, 0 );
}


  oledCommand(0xA7);          //--SSD1308_Inverse_Display_Cmd :  0x80 0xA7

this order should give 0x3C as a write order (1bit shifted) then the 0x80 (cmd) then 0xA7

instead of that

I have a strange of a beginning with  8 bits clk, with 0 than the Stop than the addy in write mode, no first byte then the end byte??? and no stop bit

if I try to add the while it stops working..

Thanks for your help

  • 0
    Intellectual 860 points

    here is the code that works

    //-----------------------------------------------------------------------------
int16_t i2c1Xfer(
	Uint8 address,
	Uint8* wdata, int wsize,
	Uint8* rdata, int rsize )
{
Uint16 i;
    I2caRegs.I2CSAR = address;           			// I2C slave address

    I2caRegs.I2CCNT = wsize;					// Setup number of bytes to send

	I2caRegs.I2CMDR.all = 0x6E20; 				// Send the TX FIFO :   0110 1110 0010 0000
//		I2caRegs.I2CMDR.bit.NACKMOD = 0;			// NACK mode bit
//		I2caRegs.I2CMDR.bit.FREE = 1;				// Run free I2C when suspended
//		I2caRegs.I2CMDR.bit.STT = 1;				// START condition bit
//		I2caRegs.I2CMDR.bit.STP = 1;				// STOP condition bit
//		I2caRegs.I2CMDR.bit.MST = 1;				// Master mode
//		I2caRegs.I2CMDR.bit.TRX = 1;				// Transmitter mode
//		I2caRegs.I2CMDR.bit.XA = 0;					// 7-bit addressing mode
//		I2caRegs.I2CMDR.bit.RM = 0;					// Nonrepeat mode
//		I2caRegs.I2CMDR.bit.DLB = 0;				// Digital loopback mode is disabled
//		I2caRegs.I2CMDR.bit.IRS = 1;				// The I2C module is enabled
//		I2caRegs.I2CMDR.bit.STB = 0;				// The I2C module is not in the START byte mode
//		I2caRegs.I2CMDR.bit.FDF = 0;				// Free data format mode is disabled
//		I2caRegs.I2CMDR.bit.BC = 0;					// 8 bits per data byte

	for (i=0; i<wsize; i++)
		{
		I2caRegs.I2CDXR = *(wdata+i);
		while(!I2caRegs.I2CSTR.bit.XRDY);
		}


	return I2C_SUCCESS;
}

    I had to wait that a data is realy transmitted before putting again in the TX FIFO

    If you have a better idea than waiting for that fifo, please let me know

    (using interrupt on FIFO can not be done because of te way data are sent)

  • 0 in reply to Lotfi BAGHLI
    Guru 30330 points
    Lotfi,

    You should be able to write all of the data to be transmitted, and it will be send in FIFO order.

    If you use the following code instead, do you still have the issue?

    int i2cxfer()
    {
    I2caRegs.I2CSAR = address; // I2C slave address

    while(!I2caRegs.I2CSTR.bit.BB == 1);// ensure the bus is not busy before transmitting

    I2caRegs.I2CCNT = wsize; // Setup number of bytes to send

    for(i=0; i<wsize;i++) {
    I2caRegs.I2CDXR = *(wdata+i); // fill fifo with data
    }

    I2caRegs.I2CMDR.all = 0x6E20; // start the transfer

    return I2C_SUCESS; // if you want any error detection, you might want to tie some actual check to this value.
    }


    The above code was an adaptation of the I2C_eeprom example from C2000Ware.

    Thanks,
    Mark
  • 0 in reply to Lotfi BAGHLI
    Intellectual 860 points

    I put the code on github for those who want to use it

    https://github.com/blotfi/c2000_OLED_SSD1306

  • 0 in reply to Mark Labbato
    Intellectual 860 points
    Thanks Mark, but my data is more than the 4 bytes depth FIFO. It can be up to 9 bytes
    So we need to wait the I2C to complete the transfer before putting new data in I2caRegs.I2CDXR
    Check my routines on
    github.com/.../c2000_OLED_SSD1306
  • 0 in reply to Lotfi BAGHLI
    Guru 30330 points
    Lotfi,

    I am glad that you were able to get it working and thanks for sharing your code! Hopefully others viewing this thread in the future will find it useful.

    -Mark