msp430 UART wie funktioniert's?

[Reinhold Schopf (Gast)]

Hallo,
möchte vom MSP 430 F1121A mehrere Zeichen über die Serie Schnittstelle
senden und empfangen.

Beispielprogramm habe ich von Texas Instruments runtergeladen.

Leider weiß ich nicht, wie ich das Programm dazu bringe, für mich
Zeichen zu senden bzw. zu empfangen.

Scheinbar ist dieses Problem so trivial, dass es von Texas Instruments
nicht behandelt wird.

Danke für euere Hilfe!!

Reinhold


Anbei das Programm-Listing von TI.:

---------------------------------------------

//********************************************************************** 
********
//  MSP-FET430x110 Demo - Timer_A UART 9600 Echo, HF XTAL ACLK
//
//  Description: Use timer_A CCR0 hardware output modes and SCCI data
latch to
//  to implement UART function @ 9600 baud. Software does not directly
read and
//  write to RX and TX pins, instead proper use of output modes and
SCCI data
//  latch are demonstrated. Use of these hardware features eliminates
ISR
//  latency effects as hardware insures that output and input bit
latching and
//  timing are perfectly synchronised with timer_A regardless of other

//  software activity. In the Mainloop the UART function readies the
UART to
//  receive one character and waits in LPM0 with all activity interrupt
driven.
//  After a character has been received, the UART receive function
forces exit
//  from LPM0 in the Mainloop which echo's back the received
character.
//  ACLK = MCLK = TACLK = HF XTAL = 3.579545MHz
//  //*An external 3.579545Hz XTAL on XIN XOUT is required for
ACLK*//
//
//                MSP430F1121
//            -----------------
//        /|\|              XIN|-
//         | |                 | 3.58Mhz
//         --|RST          XOUT|-
//           |                 |
//           |   CCI0A/TXD/P1.1|-------->
//           |                 | 9600 8N1
//           |   CCI0B/RXD/P2.2|<--------
//
#define RXD   0x04                      // RXD on P2.2
#define TXD   0x02                      // TXD on P1.1

//  Conditions for 9600 Baud HW/SW UART, ACLK = 3.579545MHz

#define Bitime_5  0x0BA                 // ~ 0.5 bit length
#define Bitime  0x175                   // 104 us ~ 9596 baud

unsigned int RXTXData;
unsigned char BitCnt;

void TX_Byte (void);
void RX_Ready (void);

//  M.Buccini
//  October 2003
//  Built with IAR Embedded Workbench Version: 1.26B
//  January 2004
//  Updated for IAR Embedded Workbench Version: 2.21B
//********************************************************************** 
********


#include <msp430x11x1.h>

void main (void)
{
  unsigned int i;
  WDTCTL = WDTPW + WDTHOLD;             // Stop watchdog timer

  BCSCTL1 |= XTS;                       // ACLK = LFXT1 = HF XTAL

  do
  {
  IFG1 &= ~OFIFG;                       // Clear OSCFault flag
  for (i = 0xFF; i > 0; i--);           // Time for flag to set
  }
  while ( IFG1 & OFIFG );               // OSCFault flag still set?


  BCSCTL2 |= SELM_3;                    // MCLK = LFXT1 (safe)

  CCTL0 = OUT;                          // TXD Idle as Mark
  TACTL = TASSEL_1 + MC_2;              // ACLK, continuous mode
  P1SEL = TXD;                          // P1.1/TA0 for TXD function
  P1DIR = TXD;                          // TXD output on P1
  P2SEL = RXD;                          // P2.2/TA0 as RXD input

// Mainloop
  for (;;)
  {
  RX_Ready();                           // UART ready to RX one Byte
  _BIS_SR(CPUOFF + GIE);                // Enter LPM0 w/ interr until
char RXed
  TX_Byte();                            // TX Back RXed Byte Received
  }
}


// Function Transmits Character from RXTXData Buffer
void TX_Byte (void)
{
  BitCnt = 0xA;                         // Load Bit counter, 8data +
ST/SP
  CCR0 = TAR;                           // Current state of TA counter
  CCR0 += Bitime;                       // Some time till first bit
  RXTXData |= 0x100;                    // Add mark stop bit to
RXTXData
  RXTXData = RXTXData << 1;             // Add space start bit
  CCTL0 = OUTMOD0 + CCIE;               // TXD = mark = idle
  while ( CCTL0 & CCIE );               // Wait for TX completion
}


// Function Readies UART to Receive Character into RXTXData Buffer
void RX_Ready (void)
{
  BitCnt = 0x8;                         // Load Bit counter
  CCTL0 = SCS + CCIS0 + OUTMOD0 + CM1 + CAP + CCIE;   // Sync, Neg
Edge, Capture
}


// Timer A0 interrupt service routine
#pragma vector=TIMERA0_VECTOR
__interrupt void Timer_A (void)
{
  CCR0 += Bitime;                       // Add Offset to CCR0

// RX
  if (CCTL0 & CCIS0)                    // RX on CCI0B?
  {
    if( CCTL0 & CAP )                   // Capture mode = start bit
edge
    {
    CCTL0 &= ~ CAP;                     // Switch from capture to
compare mode
    CCR0 += Bitime_5;
    }
    else
    {
    RXTXData = RXTXData >> 1;
      if (CCTL0 & SCCI)                 // Get bit waiting in receive
latch
      RXTXData |= 0x80;
      BitCnt --;                        // All bits RXed?
      if ( BitCnt == 0)
//>>>>>>>>>> Decode of Received Byte Here
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
      {
      CCTL0 &= ~ CCIE;                  // All bits RXed, disable
interrupt
      _BIC_SR_IRQ(CPUOFF);              // Clear LPM0 bits from 0(SR)
      }
//>>>>>>>>>> Decode of Received Byte Here
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
    }
  }
// TX
  else
  {
    if ( BitCnt == 0)
    CCTL0 &= ~ CCIE;                    // All bits TXed, disable
interrupt
    else
    {
      CCTL0 |=  OUTMOD2;                // TX Space
      if (RXTXData & 0x01)
      CCTL0 &= ~ OUTMOD2;               // TX Mark
      RXTXData = RXTXData >> 1;
      BitCnt --;
    }
  }
}

[KoF (Gast)]

http://www.mikrocontroller.net/forum/read-2-70044.html

hatte mal das selbe prob... der denkansatz steht dort, das fertige prog
( & source) steht mir leider nichtmehr zur verfügung, aber helfen kann
das bisherige auch ;-)