MSP-EXP430FR5969: MSP-EXP430FR5969

Hi,

<<< I want to take some string using UART and return the same back using interrupt.
Which hardware sends your string and which hardware is receiver?

Hello Tushar,
I would recommend you to start with the code examples available from the TI-Resource Explorer coming with the our IDE Code Composer Studio (CCS), which is available for download from the TI web page.

When you open the Resource Explorer in CCS and go on the left window to Software >> MSP430Ware - v3.80.04.05 >> Devices >> MSP430FR5XX_6XX >> MSP430FR5969 >> Peripheral Examples >> Register Level you can find various examples including multiple for UART . There is also a simple loop back code example msp430fr59xx_euscia0_uart_03.c
This is a tested code example, which you can use to verify your HW. After successful verification, you could modify it for your purposes step by step.

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//******************************************************************************
// MSP430FR59xx Demo - USCI_A0 External Loopback test @ 115200 baud
//
// Description: This demo connects TX to RX of the MSP430 UART
// The example code shows proper initialization of registers
// and interrupts to receive and transmit data. If data is incorrect P1.0 LED is
// turned ON.
// ACLK = n/a, MCLK = SMCLK = BRCLK = default DCO = 1MHz
//
//
// MSP430FR5969
// -----------------
// RST -| P2.0/UCA0TXD|----|
// | | |
// -| | |
// | P2.1/UCA0RXD|----|
// | |
// | P1.0|---> LED
//
// P. Thanigai
// Texas Instruments Inc.
// August 2012
// Built with CCS V4 and IAR Embedded Workbench Version: 5.5
//******************************************************************************
#include <msp430.h>

volatile unsigned char RXData = 0;
volatile unsigned char TXData = 1;

int main(void)
{
WDTCTL = WDTPW | WDTHOLD; // Stop watchdog

// Configure GPIO
P1OUT &= ~BIT0; // Clear P1.0 output latch
P1DIR |= BIT0; // For LED on P1.0
P2SEL1 |= BIT0 | BIT1; // USCI_A0 UART operation
P2SEL0 &= ~(BIT0 | BIT1);

// Disable the GPIO power-on default high-impedance mode to activate
// previously configured port settings
PM5CTL0 &= ~LOCKLPM5;

// Configure USCI_A0 for UART mode
UCA0CTLW0 = UCSWRST; // Put eUSCI in reset
UCA0CTL1 |= UCSSEL__SMCLK; // CLK = SMCLK
UCA0BR0 = 8; // 1000000/115200 = 8.68
UCA0MCTLW = 0xD600; // 1000000/115200 - INT(1000000/115200)=0.68
// UCBRSx value = 0xD6 (See UG)
UCA0BR1 = 0;
UCA0CTL1 &= ~UCSWRST; // release from reset
UCA0IE |= UCRXIE; // Enable USCI_A0 RX interrupt

while (1)
{
while(!(UCA0IFG & UCTXIFG));
UCA0TXBUF = TXData; // Load data onto buffer

__bis_SR_register(LPM0_bits | GIE); // Enter LPM0, interrupts enabled
}
}

#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=USCI_A0_VECTOR
__interrupt void USCI_A0_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(USCI_A0_VECTOR))) USCI_A0_ISR (void)
#else
#error Compiler not supported!
#endif
{
switch(__even_in_range(UCA0IV,USCI_UART_UCTXCPTIFG))
{
case USCI_NONE: break;
case USCI_UART_UCRXIFG:
RXData = UCA0RXBUF; // Read buffer
if(RXData != TXData) // Check value
{
P1OUT |= BIT0; // If incorrect turn on P1.0
while(1); // Trap CPU
}
TXData++; // increment data byte
__bic_SR_register_on_exit(LPM0_bits); // Exit LPM0 on reti
break;
case USCI_UART_UCTXIFG: break;
case USCI_UART_UCSTTIFG: break;
case USCI_UART_UCTXCPTIFG: break;
}
}

Best regards
Peter

I suggest you start with Example msp430fr59xx_euscia0_uart_03.c (slac536k, "Tools and Software" on the Product page).

To get a physical loopback, jumper between the TXD and RXD pins.

P2SEL1 |= BIT0 | BIT1; // USCI_A0 UART operation
P2SEL0 &= ~(BIT0 | BIT1);
Your code has mentioned above lines.

But for MSP-EXP430FR5969, RXD & TXD pins are 2.6 2.5,
So i think the code should be as mentioned below
Correct if iam wrong.
P2SEL1 |= BIT5 | BIT6; // USCI_A0 UART operation
P2SEL0 &= ~(BIT5 | BIT6);

Also instead of checking for wrong data, iput check for the correct data and changed as follows

if(RXData == TXData) // Check value
{
P1OUT |= BIT0; // If incorrect turn on P1.0
while(1); // Trap CPU
}

But still it is not working.

Thank you

There is no special hardware. I just have MSP-EXP430FR5969 development board connected to my PC and using Code Composer Studio.

> But for MSP-EXP430FR5969, RXD & TXD pins are 2.6 2.5,
Per the Launchpad UG (SLAU535B) section 6, P2.0/.1 (UCA0) are connected to back-channel TXD/RXD (J13).

Per data sheet (SLAS704F) Table 6-54, P2.5/.6 are UCA1. They are available on J4, where they are -- just to confuse things -- also marked "TXD/RXD". But they aren't what you want.

What s/w do you have on your PC to read from a COM port and send back to LP?
Do you know how to find a COM port used by the back-channel?