MSP430I2040: COM port (serial port) not working after modifying EMDC code

Hello,

Before making any changes to the UART baud rate, I would make sure the communication works at the default 250-kbaud rate. Also, don't use the USB HID bridge with a terminal. If you want to send and receive that way, you can disconnect the isolation board and the HID board and just connect to the onboard isolated RS232 port. You'll need a USB-to-RS232 adapter, which is a CDC USB device, that should show up under Windows Device Manager as a COM port.

Hi James,

I am still facing the issue.

I tried using the RS232 interface but nothing is coming on the serial terminal on the laptop.

I tried using the example, UART echo program and tried using the MSP430I2040 to MSP-ISO to MSP430F5529(HID bridge). Here I did not use the system_pre_init() in my program.

On the laptop I used realterm. With 9600 baudrate, I am seeing that whenever I transmit something from the PC, I get back some echo on the terminal but it appears to be some other characters. However the same characters keep getting echo' d back whenever I try to send a character. The printed set of characters is always the same.

Is there something wrong in what I am doing in the 2 projects.

I finally need to get the EMDC up because it has the energy values. Please let me know where I could be going wrong in both the projects.

Please help.

regards,

Rajkumar

Hi James,

Can you please give some pointers. I have a deadline coming up. Thanks.

regards,

Rajkumar

Hello,

You have two threads going at the same time with slightly different topics. Let's focus on the other one for now.

MSP430I2040: EMDC showing blank values under Results

Hi James,

Can we look at this thread for now. Thanks.

An update: I tried the UART echo program which echoes back the character on the Tx line. This is supposesd to run at (9600, N, 8, 1) baud rate.

But when I tried this program, I am getting some other characters on the COM port of the laptop. When I send 'a' I get back some other character.

(I am using the DB9 connector with a USB to serial cable to connect to the PC.)

Can you tell me what could be going wrong?

This is the UART echo program:

************************************************************************************************

#include "msp430.h"

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

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

__bis_SR_register(LPM0_bits | GIE); // Enter LPM0
__no_operation(); // For debugger


UCA0TXBUF='H';
UCA0TXBUF='e';
UCA0TXBUF='l';
UCA0TXBUF='l';
UCA0TXBUF='o';
UCA0TXBUF=' ';
UCA0TXBUF='u';
UCA0TXBUF='p';
UCA0TXBUF='\n';




}

// Echo back RXed character, confirm TX buffer is ready first
#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:
while (!(UCA0IFG&UCTXIFG)); // USCI_A0 TX buffer ready?
UCA0TXBUF = UCA0RXBUF; // TX -> RXed character
break;
case USCI_UART_UCTXIFG: break;
case USCI_UART_UCSTTIFG: break;
case USCI_UART_UCTXCPTIFG: break;
default: break;
}
}

*********************************************************************************************************************

thanks and regards,

Rajkumar

When posting code, please use the Insert > Code > C option for better readability. I've updated your latest reply accordingly.

I used the msp430i20xx_euscia0_uart_01.c code example on my EVM430-i2040S, and it worked fine. After programming the EVM in CCS, I stopped the debug session and power cycled the board. Then, I connected my RS232-to-USB adapter to my PC and the EVM's RS232 port. After opening a terminal for that adapter's COM port and setting the baud rate, anything I typed showed up in the terminal as an echo.

Make sure J8 is set to 1-2 when using the MSP-FET as the power source. Make sure you select the right COM port.