SPI connection with MSP430F2013(Master) to Arduino uno(SLAVE)

Question

I working on a project where i need measurement of a bridge circuit(strain gauge) through MCU. For that I am using a MSP430F2013 MCu with 16 bit ADC. I dont have data logging hardware for this Mcu so I am trying to connect it with Arduino Uno for recording measurements. I am not good at programming anything so till now I have pieced together code to configure ADC of MSP430 which I see is working by applying breakpoint in Code Composer studio. I have tried to set up SPI in both MSP430 and Arduino but dont know where things are going wrong( this is a blunt explantion of my problem: even if i sound a bit ignorant/stupid). It will be of great help if someone can point out mistakes here.

Here is a code of both MCU

#include <msp430.h>
    volatile unsigned int i;
    volatile unsigned int s;
int main(void)
{

  WDTCTL = WDTPW + WDTHOLD;                 // Stop watchdog timer

  BCSCTL1 = CALBC1_16MHZ;
  DCOCTL=CALDCO_16MHZ;

  //SMCLK on Pin6 (P1.4) - just for service and testing
  P1DIR |= 0x10;   //P1.4 as output
  P1SEL = 0x10;    //SMCLK to P1.4

  //I/O-Pin preparation
  P1DIR |= BIT0; //set P1.0 to output direction - for using the LED on Pin2
  P1DIR |= BIT7; //set P1.7 to output direction - as signal for data are ready to use

  //SPI settings

  USICTL0 &= ~USISWRST; //USI released for operation
  USICTL1 &= ~USII2C; //switch USI to SPI-Mode
  USICTL0 |= USIMST; //set to SPI-Master-Mode

  USICKCTL = USIDIV_3+USISSEL_2+USICKPL;
  USICTL0 |= USIPE6 + USIPE5; //SDO-Port enabled; Pin8
  USICTL0 |= USIPE7; //SDI-Port disabled; Pin9 can be used for normal in/out
  USICTL0 |= USIOE; //activate output (data goes from MSP to Warrior56)
  USICNT |= USI16B; //init load counter for 16-bit-data
  //inactive state is low
  //data is changed on the first SCLK edge and captured on the following edge

  P1DIR |= 0x01;                            // Set P1.0 to output direction
  SD16CTL = SD16REFON + SD16SSEL_1;         // 1.2V ref, SMCLK
  SD16INCTL0 = SD16INCH_1;                  // A1+/-
  SD16CCTL0 =  SD16UNI + SD16IE;            // 256OSR, unipolar, interrupt enable
  SD16AE = SD16AE1;                         // P1.1 A1+, A1- = VSS
  SD16CCTL0 |= SD16SC;                      // Set bit to start conversion



    while(1)
    {
    SD16CCTL0 |= SD16SC;
 s = SD16MEM0;
 
    for (i = 0xFFFF; i > 0; i--);           // Delay
    USICTL1 |= USIIFG;                 // Set flag and start communication
    USISR = s;

    if (USISRL = s)
      P1OUT |= 0x01;
    else
      P1OUT &= ~0x01;
    __bis_SR_register(LPM0_bits + GIE);

    }
}
#pragma vector = SD16_VECTOR; // Interrupt service routine for
__interrupt void SD16ISR(void) // conversion
{

    s = SD16MEM0;

}


//////////////////////////////////////////////////
Here is arduino code  as slave
#include <SPI.h>
char buff [50];
volatile byte indx;
volatile boolean process;

void setup (void) {
   Serial.begin (115200);
   pinMode(MOSI, INPUT); // have to send on master in so it set as output
   SPCR |= _BV(SPE); // turn on SPI in slave mode
   indx = 0; // buffer empty
   process = false;
   SPI.attachInterrupt(); // turn on interrupt
}

ISR (SPI_STC_vect) // SPI interrupt routine 
{ 
   byte c = SPDR; // read byte from SPI Data Register
   if (indx < sizeof buff) {
      buff [indx++] = c; // save data in the next index in the array buff
      if (c == '\r') //check for the end of the word
      process = true;
   }
}

void loop (void) {
   if (process) {
      process = false; //reset the process
      Serial.println (buff); //print the array on serial monitor
      indx= 0; //reset button to zero
   }
}

I have got result of ADC but not anything further( i dont know how to test usi.

Answer 1

As you are using launchpad, don't bother with arduino. Launchpad also provides USB-UART.

see https://www.embeddedrelated.com/showarticle/420.php