MSP430 UART not transmitting

Hi again Dennis,
Yes sorry I should have included that.
Here it is below.
its a voltage divider circuit.

p1.0 is connected after R1=100ohms
P1.1 is connected after R2=1K thermistor
p1.2 is being used for UART RX -EDIT: I meant  TX
p1.3 is connected after R3 =1k
and a final resistor going to ground

So its VCC (from the msp Dev board to my breadboard) > R1>R2>R3>R4>GND (from the Dev board)
p1.2 is connected to the TTL 3.3V serial cable at its RXD yellow pin with a common GND from the breadboard from the MSP Dev board.



#include "msp430g2553.h"
//#define r1 100; use later for temp conversion
#define r1 1000; //USED LATER FOR OUTPUT TEMP. CALCULATION

unsigned int Top, Middle, Bottom; //ADC RESULT VARIABLES
void Read_Value(int A);
void UART_OutUDec(unsigned long n); //RECURSION FUNCTION

int main(void)
{

WDTCTL = WDTPW + WDTHOLD; // Stop WDT
if (CALBC1_1MHZ==0xFF) // If calibration constant erased
{
while(1); // do not load, trap CPU!!
}
DCOCTL = 0; // Select lowest DCOx and MODx settings
BCSCTL1 = CALBC1_1MHZ; // Set DCO
DCOCTL = CALDCO_1MHZ;
P1SEL = BIT1 + BIT2 ; // P1.1 = RXD, P1.2=TXD
P1SEL2 = BIT1 + BIT2 ; // P1.1 = RXD, P1.2=TXD
UCA0CTL1 |= UCSSEL_2; // SMCLK
UCA0BR0 = 104; // 1MHz 9600
UCA0BR1 = 0; // 1MHz 9600
UCA0MCTL = UCBRS0; // Modulation UCBRSx = 1
UCA0CTL1 &= ~UCSWRST; // **Initialize USCI state machine**
IE2 |= UCA0RXIE; // Enable USCI_A0 RX interrupt





while(1)
{
Read_Value(1); //setup for ADC P1.0
Read_Value(2); //setup for ADC P1.1
Read_Value(3); //setup for ADC P1.3
//add in temp conversion


UART_OutUDec(Top); //TX TOP RESULT
UCA0TXBUF = 0X09; //TAB
UART_OutUDec(Middle); //TX MIDDLE/THERMISTOR RESULT
UCA0TXBUF = 0X09; //TAB
UART_OutUDec(Bottom); //TX BOTTOM RESULT
UCA0TXBUF = 0X09; //TAB
while (!(IFG2&UCA0TXIFG)); // USCI_A0 TX buffer ready?
UCA0TXBUF = 0X0A; // NEW LINE
}
}
void Read_Value(int A)
{

ADC10CTL0=0x00; // Stop ADC
if(A==1)
{
ADC10CTL1=INCH_0+ ADC10SSEL_3; // Input Channel A0 and SMCLK
ADC10AE0=0x01; // Enable analog input for p1.0
}
if(A==2)
{
ADC10CTL1=INCH_1+ ADC10SSEL_3; // Input Channel A1 and SMCLK
ADC10AE0=0x02; // Enable analog input for p1.1
}
if(A==3)
{
ADC10CTL1=INCH_3+ ADC10SSEL_3; // Input Channel A3 and SMCLK
ADC10AE0=0x08; // Enable analog input for p1.3
}

ADC10CTL0= ADC10ON + ENC; // Turn on ADC and Enable Conversion
ADC10CTL0=ADC10CTL0 | ADC10SC; // start conversion

while(ADC10CTL1 & ADC10BUSY) // wait until conversion is complete
{
}
if(A==1)
{
Top=ADC10MEM; // ADC VALUE top_R100
}
if(A==2)
{
Middle=ADC10MEM; // ADC VALUE Middle/ 1k Thermistor
}
if(A==3)
{
Bottom=ADC10MEM; // ADC VALUE Bottom_R100K
}
}




//}
void UART_OutUDec(unsigned long n)
{
// This function uses recursion to convert decimal number
// of unspecified length as an ASCII string
if(n >= 10)
{

UART_OutUDec(n/10);
n = n%10;
}
while (!(IFG2&UCA0TXIFG));
UCA0TXBUF=(n+'0'); /* n is between 0 and 9 */
}

Hi James,

I made some changes to your program:

#include "msp430g2553.h"



unsigned int Top, Middle, Bottom;      // ADC RESULT VARIABLES

void Read_Value( int A );              // Read ADC values
void UART_OutUDec( unsigned long n );  // Convert result to ASCII decimals
void UART_output( char data );         // Output UART data



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

  if( CALBC1_1MHZ == 0xFF )            // If calibration constant erased
  {
    while( 1 );                        // Do not load, trap CPU!!
  }

  DCOCTL    = 0;                       // Select lowest DCOx and MODx settings
  BCSCTL1   = CALBC1_1MHZ;             // Set DCO
  DCOCTL    = CALDCO_1MHZ;

  P1SEL     = (BIT1 | BIT2);           // P1.1 = RXD, P1.2 = TXD
  P1SEL2    = (BIT1 | BIT2);           // P1.1 = RXD, P1.2 = TXD

  UCA0CTL1  = UCSWRST;                 // USCI reset
  UCA0CTL1 |= UCSSEL_2;                // SMCLK
  UCA0BR0   = 104;                     // 1MHz 9600
  UCA0BR1   = 0;                       // 1MHz 9600
  UCA0MCTL  = UCBRS0;                  // Modulation UCBRSx = 1
  UCA0CTL1 &= ~UCSWRST;                // Release USCI from reset
  IE2      |= UCA0RXIE;                // Enable USCI_A0 RX interrupt

  while( 1 )
  {
    Read_Value( 1 );                   // Setup for ADC P1.0
    Read_Value( 2 );                   // Setup for ADC P1.1
    Read_Value( 3 );                   // Setup for ADC P1.3
    //add in temp conversion

    UART_OutUDec( Top );               // TX TOP RESULT
    UART_output( 0x09 );               // TAB
    UART_OutUDec( Middle );            // TX MIDDLE / THERMISTOR RESULT
    UART_output( 0x09 );               // TAB
    UART_OutUDec( Bottom );            // TX BOTTOM RESULT
    UART_output( 0x09 );               // TAB
    UART_output( 0x0A );               // NEW LINE
  }
}



void Read_Value( int A )
{
  ADC10CTL0 = 0x00; // Stop ADC

  if( A == 1 )
  {
    ADC10CTL1 = INCH_0 | ADC10SSEL_3;  // Input Channel A0 and SMCLK
    ADC10AE0 = 0x01;                   // Enable analog input for p1.0
  }

  if( A == 2 )
  {
    ADC10CTL1 = INCH_1 | ADC10SSEL_3;  // Input Channel A1 and SMCLK
    ADC10AE0 = 0x02;                   // Enable analog input for p1.1
  }

  if( A == 3 )
  {
    ADC10CTL1 = INCH_3 | ADC10SSEL_3;  // Input Channel A3 and SMCLK
    ADC10AE0 = 0x08;                   // Enable analog input for p1.3
  }

  ADC10CTL0 = ADC10ON | ENC;           // Turn on ADC and Enable Conversion
  ADC10CTL0 = ADC10CTL0 | ADC10SC;     // Start conversion

  while( ADC10CTL1 & ADC10BUSY )       // Wait until conversion is complete
  {
  }

  if( A == 1 )
  {
    Top = ADC10MEM;                    // ADC VALUE top_R100
  }

  if( A == 2 )
  {
    Middle = ADC10MEM;                 // ADC VALUE Middle/ 1k Thermistor
  }

  if( A == 3 )
  {
    Bottom = ADC10MEM;                 // ADC VALUE Bottom_R100K
  }
}



void UART_OutUDec( unsigned long n )
{
  UART_output( (n / 1000) + '0' );
  n %= 1000;
  UART_output( (n / 100) + '0' );
  n %= 100;
  UART_output( (n / 10) + '0' );
  UART_output( (n % 10) + '0' );
}



void UART_output( char data )
{
  while( !(IFG2 & UCA0TXIFG) );
  UCA0TXBUF = data;
}

Please try it and have a look if it works as expected. Then we can discuss it if you want.

Dennis

Hi Dennis,

Thanks for your revised code,

I tried it in a new project and it compiles with no errors. Ive been stepping through the code but it seems to have the same issue where its always in the loop for the uart IFG interrupt.

I tried clicking about  100 times on the debugger but it never leaves the loop.

I cant see anything on hyperterminal, and Ive tried the arduino serial monitor just in case its a windows 10 issue.

The drivers for the ftdi cable are installed and its a ttl 3.3v cable, Ive even tried powering the MSP430 launchpad with the Vout of the FTDI cable and removing the MSP430 usb cable in case there was some sort of conflict.

I am not sure if its a hardware setup problem or a software one.

Thanks for all your help so far Dennis.

James Woodrow said:

where its always in the loop for the uart IFG interrupt

Which one do you mean? Can you post the line number? Do you have optimizations completely turned off for debugging? Right-click on your project in the resource explorer and select properties, then go to optimization and switch it off.

Is there anyone else that can test the code with a terminal program?

Dennis

Hi Dennis,
I have hyper terminal set as 9600 baud, data bits 8, parity: none, stop bits 1, flow control: none
The yellow (RXD) of the ftdi is connected to P1.2 (UART TX) there is a common ground black from the ftdi between the breadboard and launchpads GND. The FTDI Vout(Red) is connected to to the breadboard and VCC of the Launchpad and is powering it and the resistor circuit.
Ive also got the jumpers removed from P1.0 and p1.6 so the LED's are connected, but P1.6 isn't being used but I have removed the jumper anyway.

Ive disabled optimizations in the C/C++ compiler  and its set at none from 'low'

My EXP430G2 has the hardware UART

The line it gets stuck at is 118,

I try to repeatedly step into it but it never continues.

Thanks

In my code I found a line that you can delete (but this has nothing to do with your problem):

n %= 10;

I've changed it in my posted code lines.

Dennis

Could you test another terminal program or rename the COM-port? I know from some programs that do not work with higher COM-port numbers. Maybe that is the issue.

You can try HTerm:

It runs without installation.

Dennis

hmm.. i think the problem may be the setup of the MSP430 IAR program, It seem that when i pulled out my new MSP430 with led blink installed and tried to download the code to the device it went to the debug/simulate window where i can step through the code but it doesnt appear to be actually installed on the msp430 device. any ideas

Hello James,

there seems to be a few potential points of failure here in the communication chain. Let's take a step back and see what we can get working in order to narrow down the issue. You are using a MSP430G2553 Launchpad correct? If so can you load the example code provided with MSP430Ware titled  msp430g2xx3_uscia0_uart_08_9600.c  (USCI_A0, UART 9600 Full-Duplex Transceiver, 32kHz ACLK) ? If you do not have MSPWare downloaded on your computer, please checkout CCSCloud or our Cloud Resource Explorer to quickly download this example to your device.  From this example, let's change the clock settings and subsequent UART Baud Settings to fit with what you are doing with your code. This is assuming you are not using an LF XTAL for ACLK.  Make sure to have the jumper settings to HW UART mode and connect device directly to your PC via USB. This should work with any terminal program once you point it to the MSP430 Application UART. Once your PC has valid communication with the LP, we can rule out the PC and its programs the cause of your issue here. From there, let's remove the jumpers and USB cable and place your TTL Cable setup with the same example SW on the MSP430. If this fails, we have an issue with the TTL Cable setup, if it succeeds then we need to concentrate on your original code.

Please post back with your questions or results.

Regards,

JH