MSP432 Generate SPI Data to Feed DAC8564 ?

Chang-shun Liu

Other Parts Discussed in Thread: DAC8564, MSP430F449

Hello,

I want to digitize an analog signal, manipulate (curve) it, and then convert it back to analog domain for measurement purpose.

My friend and I are using MSP432P401R MCU with its ADC, and along with TI DAC8564. I need 16-bit DAC resolution so MUST use this external DAC8564. (Other MCUs with embedded DACs only provide 12-bit resolution). The ADC's function can be enabled now, but we don't know how to convert the ADC's 16-bit data to a suitable SPI format to feed DAC8564. Does anyone know how to write the code ?

We found an example code for MSP430F449 to feed a DAC8564 but couldn't work if we just apply this code to our MSP432P401R directly.

Does anyone know how to fix it ? (The code is attached, please see "dac.c")

Thank you very much !

dac.c

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/****************************************************************/
/* FILENAME: main.c                                         */
/* DESCRIPTION: This program uses the MSP430F449 to write 256   */
/*    samples to the DAC8564/5.                                 */
/*    The samples are generated by sine/cosine functions        */
/*                                                              */
/* Author: Jojo Parguian                                        */
/* Precision Analog Applications, Dallas, TX                    */
/* CREATED 06/18/08(C) BY TEXAS INSTRUMENTS INCORPORATED.   */
/* VERSION: 01                          */
/****************************************************************/
#include <msp430x44x.h>
#include <math.h>
/**************** Function prototypes ***********************************/
/*                                                                      */
void init_sys(void);                  /* MSP430 Initialisation routine  */
void setupClock(int);
void delay(int);                      /* Software delay                 */
void dac_convert(int, int);           /* Do the dac conversion          */
void InitTables(int);
void int_ref_disable(int, int, int);  /* Disable the Internal Reference */
void int_ref_enable(void);            /* Enable the Internal Reference  */
void int_ref_ON (void);               /* Enable the Internal Reference  */
                                      /* all the time                   */
/************************************************************************/
/*                                                                      */
/* HPA449 variable declarations                                         */
/*                                                                      */
/************************************************************************/
#define DAC_CS       0x20  //p3.5
#define LDAC         0x40  //p3.6
#define Resonator (0)
#define disable_ref (0)
#define enable_ref (0)
/************************************************************************/
/*                                                                      */
/* main() variable declarations                                         */
/*                                                                      */
/************************************************************************/
#define BLOCK_SZ         256          /* size of data buffer */
#define TABLE_SIZE       256
int sinetable[TABLE_SIZE], costable[TABLE_SIZE], byte0, byte1, byte2;
int i, y;
/******************************************************************************\
* Function: InitTables()
* Description: Initializes Sine and Cosine Values
\******************************************************************************/
void main(void)
{
  int  val0, val1, val2;
  int  dac_A, dac_B, dac_C, dac_D;
  setupClock(Resonator);
  init_sys();                       // Initialise the MSP430
  InitTables(1);                        // Number defines the cycles per period
      if (disable_ref)
          {
            val0 = 0x00;
            val1 = 0x20;
            val2 = 0x01;
            int_ref_disable(val0, val1, val2);
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

/****************************************************************/
/* FILENAME: main.c                            		        */
/* DESCRIPTION: This program uses the MSP430F449 to write 256 	*/
/*    samples to the DAC8564/5.                                 */
/*    The samples are generated by sine/cosine functions        */
/*                                                              */
/* Author: Jojo Parguian                                        */
/* Precision Analog Applications, Dallas, TX                    */
/* CREATED 06/18/08(C) BY TEXAS INSTRUMENTS INCORPORATED.  	*/
/* VERSION: 01   						*/
/****************************************************************/
#include <msp430x44x.h>
#include <math.h>

/**************** Function prototypes ***********************************/
/*                                                                      */
void init_sys(void);                  /* MSP430 Initialisation routine  */
void setupClock(int);
void delay(int);                      /* Software delay                 */
void dac_convert(int, int);           /* Do the dac conversion          */
void InitTables(int);
void int_ref_disable(int, int, int);  /* Disable the Internal Reference */
void int_ref_enable(void);            /* Enable the Internal Reference  */
void int_ref_ON (void);               /* Enable the Internal Reference  */
                                      /* all the time                   */

/************************************************************************/
/*                                                                      */
/* HPA449 variable declarations                                         */
/*                                                                      */
/************************************************************************/
#define DAC_CS       0x20  //p3.5
#define LDAC         0x40  //p3.6
#define Resonator (0)
#define disable_ref (0)
#define enable_ref (0)

/************************************************************************/
/*                                                                      */
/* main() variable declarations                                         */
/*                                                                      */
/************************************************************************/
#define BLOCK_SZ         256          /* size of data buffer */
#define TABLE_SIZE       256

int sinetable[TABLE_SIZE], costable[TABLE_SIZE], byte0, byte1, byte2;
int i, y;

/******************************************************************************\
* Function: InitTables()
* Description: Initializes Sine and Cosine Values
\******************************************************************************/
void main(void)
{
  int  val0, val1, val2;
  int  dac_A, dac_B, dac_C, dac_D;
  setupClock(Resonator);
  init_sys();                   	// Initialise the MSP430
  InitTables(1);                        // Number defines the cycles per period

      if (disable_ref)
          {
            val0 = 0x00;
            val1 = 0x20;
            val2 = 0x01;

            int_ref_disable(val0, val1, val2);
          }
      else if (enable_ref)
      {
        int_ref_enable();
      }
      else
      {
        int_ref_ON();
      }


      do {
          dac_A = 0x0;
          dac_B = 0x2;
          dac_C = 0x4;
          dac_D = 0x26;

           for(i=0; i<BLOCK_SZ; i++)
           {
            dac_convert(dac_A, sinetable[i]);  // Send sine values to the DAC A = sinetable[i]
            dac_convert(dac_B, sinetable[i]);  // Send sine values to the DAC B = sinetable[i]
            dac_convert(dac_C, sinetable[i]);  // Send sine values to the DAC C = sinetable[i]
            dac_convert(dac_D, sinetable[i]);  // Send sine values to the DAC D = sinetable[i]
           }
         }
       while (1);              // Endless Loop
} /*end of main*/			      	

/************************************************************/
/* Prototype - init_table                                   */
/*                                                          */
/*  Description                                             */
/*  This prototype initialises the waveform table           */
/************************************************************/
void InitTables(int cycles)
{
	int y;
	for (y = 0; y < TABLE_SIZE; y++)
	{
	  sinetable[y] = (unsigned int)((sin(2 * 3.141593659 * cycles * y / TABLE_SIZE) + 1.0) * 32767);
	  costable[y] = (unsigned int)((cos(2 * 3.141593659 * cycles * y / TABLE_SIZE) + 1.0) * 32767);
	}
}

/************************************************************/
/* Prototype - init_sys                                     */
/*                                                          */
/*  Description                                             */
/*  This prototype initialises the MSP430F449               */
/************************************************************/
void init_sys(void)
{
void setupports(void);  /* Local function prototype         */
void setupSPI(void);    /* Local function prototype         */

setupports();
setupSPI();
//  _EINT();                              // Enable interrupts
}

/************************************************************/
/* Prototype - setupClock                                     */
/*                                                          */
/*  Description                                             */
/*  This prototype sets-up the XT2 oscillator and tests     */
/*  that it has settled before moving on                    */
/************************************************************/
void setupClock (int RES)
{
    switch (RES)
    {
        case  0:
          { WDTCTL = WDTPW + WDTHOLD;
            /* D=2, N=121, no mod */
            SCFQCTL=121;
            // SCFI0 = 0100 0100
            SCFI0=0x44;
            // DCOPLUS=1, XTS_FLL=0
            // XCAPXPF=00
            FLL_CTL0=0x80;
            // SMCLK=0, XT2OFF=1, SELMX=00, SELS=0, FLL_DIVX=10
            // FLL_CTL1= 0010 0010
            FLL_CTL1=0x22;
          }
          break;
        case  1:
          { WDTCTL = WDTPW + WDTHOLD;           // Stop watchdog timer
            FLL_CTL0&=XT2OFF;                    // Switch on the XT2 osc.
            FLL_CTL1|=SELM_XT2+SELS;                // Select XT2 osc. for
            // Test the osc. flag bit
            do {
                IFG1 &= ~OFIFG;            // Clear the OFIFG bit
                } while (OFIFG&IFG1);      //
          }
          break;
    }
}

/************************************************************/
/* Prototype - setupports                                   */
/*  Description                                             */
/*  This prototype sets-up the GPIO ports as appropriate    */
/************************************************************/
void setupports (void)
{
// SPI port for DAC
P3SEL = BIT3 + BIT2 + BIT1;                 // Bits 3, 2 & 1 are assigned as SPI specific pins
P3DIR = DAC_CS+LDAC;                        // Set the DAC_CS bit as an output
P3OUT = DAC_CS+LDAC;                        // De-assert DAC_CS for the DAC - HIGH
P4SEL = BIT5 + BIT3 + BIT2;

//SetupInterrupts
P1IFG |= 0x00;
P1IES |= 0x40;
P1IE |= 0x40;
}

/************************************************************/
/* Prototype - setupSPI                                     */
/*                                                          */
/*  Description                                             */
/*  This prototype sets-up the P3 for communication via SPI */
/************************************************************/
void setupSPI (void)

/************************************************************/
/* System definitions                                       */
/************************************************************/
#define     SPI0en       0x40
#define     SPI1en       0x10

{
	

ME1 |= USPIE0;                      // Module Enable - SPI1
U0CTL &= ~SWRST;                    // Make sure the RESET bit is off
U0CTL |= CHAR + SYNC + MM;          // USART0 module operation
                                    // CHAR = 1 => 8-bit data
                                    // SYNC = 1 => SPI selected
                                    // MM = 1 => master mode,
U0TCTL |= CKPH + CKPL + SSEL0 + SSEL1 + STC;      // USART0 Tranmit control register
U0BR0  = 0x02;                      // Divide SMCLK by 2 => transfer clock
U0BR1  = 0x00;                      //
U0MCTL = 0x00;                      // Modulation control - not used. Ensure
                                    // all these bits are reset
}

/************************************************************/
/* Prototype - delay                                        */
/*  Description                                             */
/*  This prototype gives a delay of around 1 second         */
/************************************************************/

void delay(int time)
      {
      unsigned int i;
      for (i = 0; i < time; i++);
      }
/************************************************************/
/* Prototype - int_ref_disable                              */
/*  Description                                             */
/*  This prototype disables the DAC internal reference      */
/************************************************************/
void int_ref_disable (val0, val1, val2)
{
  byte0 = val0;
  byte1 = val1;
  byte2 = val2;

  P3OUT &= ~(DAC_CS);              // Set DAC /CS low
  while ((IFG1 & UTXIFG0) == 0);
        U0TXBUF = byte2 ;          // Send clocks to the DAC, this shifts CMD byte
	                           // Wait until all 8 bits have been received.
  while ((IFG1 & UTXIFG0) == 0);
        U0TXBUF = byte1;           // Send clocks to the DAC, this shifts MSB byte
	                           // Wait until all 8 bits have been received.
  while ((IFG1 & UTXIFG0) == 0);
        U0TXBUF = byte0;           // Send clocks to the DAC, this shifts LSB byte
	                           // Wait until all 8 bits have been received.
  delay(3);	                   // Wait until all 8 bits have been received.
  P3OUT |= (DAC_CS);               // Set DAC /CS high
}

/************************************************************/
/* Prototype - int_ref_enable                               */
/*  Description                                             */
/*  This prototype enables the DAC internal reference       */
/************************************************************/
void int_ref_enable (void)
{
  byte0 = 0x00;
  byte1 = 0x00;
  byte2 = 0x01;

  P3OUT &= ~(DAC_CS);                // Set DAC /CS low for 1st write cycle
  while ((IFG1 & UTXIFG0) == 0);
        U0TXBUF = byte2 ;            // Send clocks to the DAC, this shifts CMD byte
	                             // Wait until all 8 bits have been received.
  while ((IFG1 & UTXIFG0) == 0);
        U0TXBUF = byte1;             // Send clocks to the DAC, this shifts MSB byte
	                             // Wait until all 8 bits have been received.
  while ((IFG1 & UTXIFG0) == 0);
        U0TXBUF = byte0;             // Send clocks to the DAC, this shifts LSB byte
	                             // Wait until all 8 bits have been received.
  delay(3);	                     // Wait until all 8 bits have been received.
  P3OUT |= (DAC_CS);                 // Set DAC /CS high
}

/*******************************************************************/
/* Prototype - int_ref_ON                                          */
/*  Description                                                    */
/*  This prototype enables the DAC internal reference all the time */
/*******************************************************************/
void int_ref_ON (void)
{
  byte0 = 0x00;
  byte1 = 0x10;
  byte2 = 0x01;

  P3OUT &= ~(DAC_CS);                // Set DAC /CS low for 2nd write cycle
  while ((IFG1 & UTXIFG0) == 0);
        U0TXBUF = byte2 ;            // Send clocks to the DAC, this shifts CMD byte
	                             // Wait until all 8 bits have been received.
  while ((IFG1 & UTXIFG0) == 0);
        U0TXBUF = byte1;             // Send clocks to the DAC, this shifts MSB byte
	                             // Wait until all 8 bits have been received.
  while ((IFG1 & UTXIFG0) == 0);
        U0TXBUF = byte0;             // Send clocks to the DAC, this shifts LSB byte
	                             // Wait until all 8 bits have been received.
  delay(3);	                     // Wait until all 8 bits have been received.
  P3OUT |= (DAC_CS);                 // Set DAC /CS high
}

/************************************************************/
/* Prototype - convert                                      */
/*  Description                                             */
/*  This prototype does the DAC conversion                  */
/************************************************************/
void dac_convert (dac_Ch, value)

{
byte0 = value >>8;
byte1 = value >>0;
byte2 = dac_Ch;

P3OUT &= ~(DAC_CS);                // Set DAC /CS low
while ((IFG1 & UTXIFG0) == 0);
      U0TXBUF = byte2 ;            // Send clocks to the DAC, this shifts CMD byte
	                           // Wait until all 8 bits have been received.
while ((IFG1 & UTXIFG0) == 0);
      U0TXBUF = byte0;             // Send clocks to the DAC, this shifts MSB byte
	                           // Wait until all 8 bits have been received.
while ((IFG1 & UTXIFG0) == 0);
      U0TXBUF = byte1 ;            // Send clocks to the DAC, this shifts LSB byte
	                           // Wait until all 8 bits have been received.

delay(1);	                   // Wait until all 8 bits have been received.
P3OUT |= (DAC_CS);                 // Set DAC /CS high

}

over 10 years ago

0 Chang-shun Liu over 10 years ago

Prodigy 30 points

MCU : MSP432P401R
The example code for MSP430F449 to write the DAC8564 is attached --> "dac.c"

0 user4318303 over 10 years ago

Prodigy 10 points

just look carefully about hardware spi U of msp430, this is a very easy thing if you have read it. If still have problems, please look the wareform through oscilloscope. Finally ,why you just change you mcu for one with DAC inside ,this is very cheap and much easier.(like 6638 or 5438)

0 Chang-shun Liu over 10 years ago in reply to user4318303

Prodigy 30 points

Thank you.
(1) What is hardware spi "U" of MSP430 ? But what I want to trouble shoot is MSP432...
(2) I want a DAC with 16-bit resolution. I believe there is no MCU with DAC inside provides 16-bit resolution, only 12-bit available.

0 Ilmars over 10 years ago in reply to Chang-shun Liu

Guru 46710 points

>We found an example code for MSP430F449 to feed a DAC8564 but couldn't work if we just apply this code to our MSP432P401R directly.
You would want to get msp432 examples regarding SPI to familiarize with SPI of particular chip, read documentation of both chips and write code or port code from mentioned ADC example msp430 code to msp432 _yourself_.

0 Albert Lu1 over 10 years ago

Intellectual 520 points

GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_PJ, GPIO_PIN0 | GPIO_PIN1, GPIO_PRIMARY_MODULE_FUNCTION);
CS_setExternalClockSourceFrequency(32768, 0);
CS_initClockSignal(CS_ACLK, CS_LFXTCLK_SELECT, CS_CLOCK_DIVIDER_1);
CS_startLFXT(CS_LFXT_DRIVE0);
/* Selecting P1.1 P1.2 and P1.3 in SPI mode */
GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P1, GPIO_PIN1 | GPIO_PIN2 | GPIO_PIN3, GPIO_PRIMARY_MODULE_FUNCTION);
/* Configuring SPI in 3wire master mode */
SPI_initMaster(EUSCI_A0_MODULE, &spiMasterConfig);
/* Enable SPI module */
SPI_enableModule(EUSCI_A0_MODULE);

/* Transmitting data to slave */
UCA0TXBUF = 0b00000000;//byte 2 to TX buffer DB23-16
while (!(MAP_SPI_getInterruptStatus(EUSCI_A0_MODULE,EUSCI_A_SPI_TRANSMIT_INTERRUPT))); //Make sure buffer is ready before loading the next byte
UCA0TXBUF = 0b11111110; //byte0;//byte 0 DB 15 14 13 12 11 10 9 8
while (!(MAP_SPI_getInterruptStatus(EUSCI_A0_MODULE,EUSCI_A_SPI_TRANSMIT_INTERRUPT)));
UCA0TXBUF = 0b11111111; //byte1;//byte DB0-13   7-6-5-4-3-2-1-0
while((UCA0STATW&BIT0));//wait for the the busy signal to clear

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MSP432 Generate SPI Data to Feed DAC8564 ?