ADC and UART

> UCA0IE |= UCTXIE0;

Remove this line. You don't have an ISR for UCA0, so your program will immediately (after _EINT()) vector off to ISR_TRAP.

More generally, you need interlocks for both the ADC and the UART:

1) You're setting ADCSC both in main and in the ADC ISR; you should do one or the other. Also, you need to wait for the ADC to complete before sending the result over the UART.

2) You're writing to UCA0TXBUF without waiting for it to become available (UCTXIFG), so you're losing bytes.

It may be useful to go through the examples in:

http://dev.ti.com/tirex/explore/node?node=ACqyBhoKY-mma1YuW1PofA__IOGqZri__LATEST

[Edit: You're setting the clock to 16MHz without setting the FRAM wait states. See Example msp430fr235x_CS_03.c:

http://dev.ti.com/tirex/explore/node?node=AKck5cmxoHuBiRVX8QJuhg__IOGqZri__LATEST

]

Thank you for your reply.  I read the example and try again , but I  receive the ADvalue from  serial port of PC ,the data is full of '0'.

My program is:

#include "msp430fr2355.h"
#include <msp430.h>
unsigned int ADvalue;
unsigned char a[2];
void Software_Trim(); // Software Trim to get the best DCOFTRIM value
#define MCLK_FREQ_MHZ 16 // MCLK = 16MHz

/******************************************************************************************
函数功能：发送一个字节数据
****************************************************************************************/
void UART_Send_Byte(unsigned char mydata) // 发送一个字节
{
UCA0TXBUF=mydata; //将数据写到数据发射缓冲器TXBUF1中，等待发射，发送完一个字节的数据为8位
while(!(UCA0IFG&UCTXIFG)); //UCTXIFG为发送器空标志，若为0表示TXBUF中有数据，为“1”表示TXBUF为空
//在此等待一个字节的数据发送完
}

void main(void)
{
WDTCTL=WDTPW+WDTHOLD;

FRCTL0 = FRCTLPW | NWAITS_1;
__bis_SR_register(SCG0); // disable FLL
CSCTL3 |= SELREF__REFOCLK; // Set REFO as FLL reference source
CSCTL1 = DCOFTRIMEN_1 | DCOFTRIM0 | DCOFTRIM1 | DCORSEL_5;// DCOFTRIM=5, DCO Range = 16MHz
CSCTL2 = FLLD_0 + 487; // DCOCLKDIV = 16MHz
__delay_cycles(3);
__bic_SR_register(SCG0); // enable FLL
Software_Trim(); // Software Trim to get the best DCOFTRIM value

CSCTL4 = SELMS__DCOCLKDIV | SELA__REFOCLK; // set default REFO(~32768Hz) as ACLK source, ACLK = 32768Hz
// default DCOCLKDIV as MCLK and SMCLK source

// Configure ADC A0 pin
P1SEL0 |=BIT0; //使能AD输入，选择的通道为P1.0
P1SEL1 |=BIT0;
// Configure UART pins
P1SEL0 |= BIT6 | BIT7; // set 2-UART pin as second function,(1.7TXD,1.6RXD)
// Disable the GPIO power-on default high-impedance mode to activate
// previously configured port settings
PM5CTL0 &= ~LOCKLPM5; // Disable the GPIO power-on default high-impedance mode
// Configure ADC12
ADCCTL0 |= ADCSHT_2 | ADCON; // ADCON, S&H=16 ADC clks
ADCCTL1 |= ADCSHP; // ADCCLK = MODOSC; sampling timer
ADCCTL2 &= ~ADCRES; // clear ADCRES in ADCCTL
ADCCTL2 |= ADCRES_2; // 12-bit conversion results
ADCMCTL0 |= ADCINCH_0; // A0 ADC input select; Vref=AVCC

// Configure UART
UCA0CTLW0 |= UCSWRST;
UCA0CTLW0 |= UCSSEL__SMCLK;
// Baud Rate calculation
// 16000000/(115200) = 134.88888,134=0x8a
// Fractional portion = 0.8888
// User's Guide Table 22-4: UCBRSx = 0xf7
// UCBRFx = int ( (134.8888-134)*16) = 14
UCA0BR0 = 0x8a; // 16000000/115200
UCA0BR1 = 0x00;
UCA0MCTLW =0xf700 | UCOS16 | UCBRF_1;
UCA0CTLW0 &= ~UCSWRST; // Initialize eUSCI

ADCIE |= ADCIE0_1; // Enable ADC conv complete interrupt // to activate previously configured port settings


while(1)
{
ADCCTL0 |= ADCENC | ADCSC; // Sampling and conversion start
__bis_SR_register(LPM0_bits | GIE); // LPM0, ADC_ISR will force exit
__no_operation(); // For debug only
a[0]=ADvalue&0xFF;
a[1]=(ADvalue>>8)&0xFF;
UART_Send_Byte(a[0]);
UART_Send_Byte(a[1]);
}
}

// ADC interrupt service routine
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=ADC_VECTOR
__interrupt void ADC_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(ADC_VECTOR))) ADC_ISR (void)
#else
#error Compiler not supported!
#endif
{
switch(__even_in_range(ADCIV,ADCIV_ADCIFG))
{
case ADCIV_NONE:
break;
case ADCIV_ADCOVIFG:
break;
case ADCIV_ADCTOVIFG:
break;
case ADCIV_ADCHIIFG:
break;
case ADCIV_ADCLOIFG:
break;
case ADCIV_ADCINIFG:
break;
case ADCIV_ADCIFG:
ADvalue = ADCMEM0;
__bic_SR_register_on_exit(LPM0_bits); // Clear CPUOFF bit from LPM0
break;
default:
break;
}
}

void Software_Trim()
{
unsigned int oldDcoTap = 0xffff;
unsigned int newDcoTap = 0xffff;
unsigned int newDcoDelta = 0xffff;
unsigned int bestDcoDelta = 0xffff;
unsigned int csCtl0Copy = 0;
unsigned int csCtl1Copy = 0;
unsigned int csCtl0Read = 0;
unsigned int csCtl1Read = 0;
unsigned int dcoFreqTrim = 3;
unsigned char endLoop = 0;

do
{
CSCTL0 = 0x100; // DCO Tap = 256
do
{
CSCTL7 &= ~DCOFFG; // Clear DCO fault flag
}while (CSCTL7 & DCOFFG); // Test DCO fault flag

__delay_cycles((unsigned int)3000 * MCLK_FREQ_MHZ);// Wait FLL lock status (FLLUNLOCK) to be stable
// Suggest to wait 24 cycles of divided FLL reference clock
while((CSCTL7 & (FLLUNLOCK0 | FLLUNLOCK1)) && ((CSCTL7 & DCOFFG) == 0));

csCtl0Read = CSCTL0; // Read CSCTL0
csCtl1Read = CSCTL1; // Read CSCTL1

oldDcoTap = newDcoTap; // Record DCOTAP value of last time
newDcoTap = csCtl0Read & 0x01ff; // Get DCOTAP value of this time
dcoFreqTrim = (csCtl1Read & 0x0070)>>4;// Get DCOFTRIM value

if(newDcoTap < 256) // DCOTAP < 256
{
newDcoDelta = 256 - newDcoTap; // Delta value between DCPTAP and 256
if((oldDcoTap != 0xffff) && (oldDcoTap >= 256)) // DCOTAP cross 256
endLoop = 1; // Stop while loop
else
{
dcoFreqTrim--;
CSCTL1 = (csCtl1Read & (~DCOFTRIM)) | (dcoFreqTrim<<4);
}
}
else // DCOTAP >= 256
{
newDcoDelta = newDcoTap - 256; // Delta value between DCPTAP and 256
if(oldDcoTap < 256) // DCOTAP cross 256
endLoop = 1; // Stop while loop
else
{
dcoFreqTrim++;
CSCTL1 = (csCtl1Read & (~DCOFTRIM)) | (dcoFreqTrim<<4);
}
}

if(newDcoDelta < bestDcoDelta) // Record DCOTAP closest to 256
{
csCtl0Copy = csCtl0Read;
csCtl1Copy = csCtl1Read;
bestDcoDelta = newDcoDelta;
}

}while(endLoop == 0); // Poll until endLoop == 1

CSCTL0 = csCtl0Copy; // Reload locked DCOTAP
CSCTL1 = csCtl1Copy; // Reload locked DCOFTRIM
while(CSCTL7 & (FLLUNLOCK0 | FLLUNLOCK1)); // Poll until FLL is locked
}