CCS/MSP430I2041: msp430i2041

Subhronil Chaudhuri

Part Number: MSP430I2041

Tool/software: Code Composer Studio

Dear all,

I want to send a string via UART, the issue is it only sends the first character, I would really appreciate some help in this regards. The code is attached below:

//Intialisation bit:

    //UART
    P1SEL0 |=   BIT2 | BIT3;                // P1.2/3 eUSCI_A Function
    P1SEL1 &= ~(BIT2 | BIT3);

    UCA0CTL1 |= UCSWRST;                    // Hold eUSCI in reset
    UCA0CTL1 |= UCSSEL_2;                   // SMCLK
    UCA0BR0   = 0xAA;                       // 9600 baud
    UCA0BR1   = 0x06;
    UCA0MCTLW = 0xD600;                     // 16.384MHz/9600 = 1706.6667 (See UG)
    UCA0CTL1 &= ~UCSWRST;                   // Release from reset
    UCA0IE   |= UCRXIE;                     // Enable RX interrupt

    // Setting the DCO to use the internal resistor. DCO will be at 16.384MHz
    CS_setupDCO(CS_INTERNAL_RESISTOR);
    CS_initClockSignal(CS_SMCLK, CS_CLOCK_DIVIDER_1);

// Interrupt routine

void USCI_A0_ISR(void)
{
    switch(__even_in_range(UCA0IV, USCI_UART_UCTXCPTIFG)) {
        case USCI_NONE: break;
        case USCI_UART_UCRXIFG:
            u = 0;
            while (!(UCA0IFG&UCTXIFG)); // USCI_A0 TX buffer ready?
            {
                sprintf(randomstr, "%d", p_results_2);// convert p_result_2 to string
                while (randomstr[u] != '\0')
                {
                    UCA0TXBUF = randomstr[u];
                  
                    u++;
                    //UCA0TXBUF = 0x0a;
                }
                UCA0TXBUF = 0x0a;
               
                UCA0TXBUF = 0x0d;
                u = 0;
            }
            break;
        case USCI_UART_UCTXIFG: break;
        case USCI_UART_UCSTTIFG: break;
        case USCI_UART_UCTXCPTIFG: break;
        default: break;
    }
}

Regards

Neal

over 7 years ago

0 JD Crutchfield over 7 years ago

TI__Mastermind 30570 points

Hey Subhronil,

I think you are not re-waiting to the TX buffer to clear before trying to write in the rest of the string. This while loop should only write 1 character, then wait for TX buffer to be ready before writing in more.

while (randomstr[u] != '\0')
                {
                    UCA0TXBUF = randomstr[u];
                  
                    u++;
                    //UCA0TXBUF = 0x0a;
                }

Regards,

0 Subhronil Chaudhuri over 7 years ago in reply to JD Crutchfield

Intellectual 560 points

Dear JD,

Thanks a lot. adding the check; "while (UCA0STATW & UCBUSY)"does the trick

 while (currentstr[u] != '\0')
                {
                    UCA0TXBUF = currentstr[u];
                    while (UCA0STATW&UCBUSY);
                    u++;
                    //UCA0TXBUF = 0x0a;
                }
Regards

Neal

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