Other Parts Discussed in Thread: CONTROLSUITE
Hi everyone, I am trying to establish communication wbetween my uC and MCP4017 (Potentiometer). My first attempt is to send "Read" request to the chip and to get a response. I have put some breakpoints inside my interrupt function to determine whether the chip is sending any response or not, be know if my request structure is correct. Here some lines code,
// I2C initialization
void I2CA_Init(void)
{
// Initialize I2C
//0101111(1) last 1 represents part of the slave address but also a Read command
I2caRegs.I2CSAR = 0x005F; // Slave address
I2caRegs.I2CPSC.all = 9; // 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
I2caRegs.I2CMDR.all = 0x0020; // Take I2C out of reset
// Stop I2C when suspended
I2caRegs.I2CFFTX.all = 0x6000; // Enable FIFO mode and TXFIFO
I2caRegs.I2CFFRX.all = 0x2040; // Enable RXFIFO, clear RXFFINT,
return;
}
// Initialization of Input/Output ports
void init_gpio(void)
{
// GPIO-32 - PIN FUNCTION = I2C SDA
GpioCtrlRegs.GPBPUD.bit.GPIO32 = 0;// Enable pull-up for GPIO32 (SDAA)
GpioCtrlRegs.GPBQSEL1.bit.GPIO32 = 3; // Asynch input GPIO32 (SDAA)
GpioCtrlRegs.GPBMUX1.bit.GPIO32 = 1;//0; // 0=GPIO, 1=I2C-SDA, 2=SYNCI, 3=ADCSOCA
//GpioCtrlRegs.GPBDIR.bit.GPIO32 = 1; // 1=OUTput, 0=INput
// GPIO-33 - PIN FUNCTION = I2C SCL
GpioCtrlRegs.GPBPUD.bit.GPIO33 = 0; // Enable pull-up for GPIO33 (SCLA)
GpioCtrlRegs.GPBQSEL1.bit.GPIO33 = 3; // Asynch input GPIO33 (SCLA)
GpioCtrlRegs.GPBMUX1.bit.GPIO33 = 1;//0; // 0=GPIO, 1=I2C-SCL, 2=SYNCO, 3=ADCSOCB
//GpioCtrlRegs.GPBDIR.bit.GPIO33 = 1; // 1=OUTput, 0=INput
}
//deactivate ADC intrrupt for test, activate I2C interrupt
I2c_interrupt_init()
{
// Disable CPU interrupts
DINT;
// Disable CPU interrupts and clear all CPU interrupt flags:
IER = 0x0000;
IFR = 0x0000;
// Initialize the PIE vector table with pointers to the shell Interrupt
// Service Routines (ISR).
// This will populate the entire table, even if the interrupt
// is not used in this example. This is useful for debug purposes.
// The shell ISR routines are found in DSP280x_DefaultIsr.c.
// This function is found in DSP280x_PieVect.c.
// InitPieVectTable();
// Enable the PIE Vector Table
PieCtrlRegs.PIECTRL.bit.ENPIE = 1;
// Interrupts that are used in this example are re-mapped to
// ISR functions found within this file.
EALLOW; // This is needed to write to EALLOW protected registers
PieVectTable.I2CINT1A = &i2c_int1a_isr;
EDIS; // This is needed to disable write to EALLOW protected registers
// Enable I2C interrupt 1 in the PIE: Group 8 interrupt 1
PieCtrlRegs.PIEIER8.bit.INTx1 = 1;
// Enable CPU INT8 which is connected to PIE group 8
IER |= M_INT8;
EINT;
}
//Start of the endless loop
for(;;)
{
if(i2c_sent == 0)
I2C_communication();
}
void I2C_communication()
{
i2c_sent = 1;
// Send slave address with 1 as last bit for Read command
// 0101111(1) == 0x5F
I2caRegs.I2CSAR = I2C_READ_SLAVE_ADDRESS;
}
interrupt void i2c_int1a_isr(void) // I2C-A
{
Uint16 IntSource;//, i;
// Read interrupt source
IntSource = I2caRegs.I2CISRC.all;
// Interrupt source = stop condition detected
if(IntSource == I2C_SCD_ISRC)
{
// If completed message was writing data, reset msg to inactive state
if (CurrentMsgPtr->MsgStatus == I2C_MSGSTAT_WRITE_BUSY)
{
CurrentMsgPtr->MsgStatus = I2C_MSGSTAT_INACTIVE;
}
}
else if(IntSource == I2C_ARDY_ISRC)
{
// NACK a no-acknowledge bit was sent during the acknowledge
// cycle on the I2C-bus.
if(I2caRegs.I2CSTR.bit.NACK == 1)
{
// STP has been set by the device to generate a STOP condition
// when the internal data counter of the I2C module counts down to 0
I2caRegs.I2CMDR.bit.STP = 1;
// (1) NACK bit received. The hardware detects that a no-acknowledge
// (NACK) bit has been received. Note: While the I2C module performs
// a general call transfer, NACK is 1, even if one or more slaves
// send acknowledgment.
I2caRegs.I2CSTR.all = I2C_CLR_NACK_BIT;
}
else if(CurrentMsgPtr->MsgStatus == I2C_MSGSTAT_SEND_NOSTOP_BUSY)
{
CurrentMsgPtr->MsgStatus = I2C_MSGSTAT_RESTART;
}
} // end of register access ready
else
{
// Generate some error due to invalid interrupt source
asm(" ESTOP0");
}
i2c_sent = 0;
// Enable future I2C (PIE Group 8) interrupts
PieCtrlRegs.PIEACK.all = PIEACK_GROUP8;
}
Thanks in advance
