//******************************************************************************
//  MSP-FET430P140 Demo - DMA1/0, Blk Mode UART1 9600 Auto RX/TX String, ACLK
//
//  Description: DMA1 is used to capture a 16 byte string from USART1. The
//  DMA1 interrupt is used to trigger DMA0 to echo back the received string.
//  USART1 is configured at 96008N1.
//  Level senstive trigger used for UTXIFG1 to prevent loss of initial edge
//  sensitive triggers - UTXIFG1 which is set at POR.
//  ACLK = 32768Hz = UCLK1, MCLK = SMCLK = default DCO ~ 800k
//  Baud rate divider with 32768hz XTAL @9600 = 32768Hz/9600 = 3.41 (000Dh 4Ah )
//  //* An external watch crystal on XIN XOUT is required for ACLK *//	
//  //* Final Production MSP430F16x(x) Device Required *//
//
//               MSP430F169
//            -----------------
//        /|\|              XIN|-
//         | |                 | 32768Hz
//         --|RST          XOUT|-
//           |                 |
//           |             P3.6|------------>
//           |                 | 9600 - 8N1
//           |             P3.7|<------------
//
//  M. Buccini / A. Dannenberg
//  Texas Instruments Inc.
//  November 2005
//  Built with IAR Embedded Workbench Version: 3.30A
//******************************************************************************

#include  <msp430x16x.h>

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop watchdog
  P3SEL = 0xC0;                             // P3.6,7 = USART1 TXD/RXD
  ME2 |= URXE1 + UTXE1;                     // Enabled UART1 RXD/TXD
  UCTL1 |= CHAR;                            // 8-bit char, SWRST=1
  UTCTL1 |= SSEL0;                          // UCLK = ACLK
  UBR01 = 0x03;                             // 9600 from 32768Hz
  UBR11 = 0x00;
  UMCTL1 = 0x4A;                            // Modulation
  UCTL1 &= ~SWRST;                          // Enable USART

  DMACTL0 = DMA1TSEL_9 + DMA0TSEL_10;       // DMA1=URXIFG1, DMA0=UTXIFG1

// Playback
  DMA0SA = 0x220;                           // Src = RAM memory
  DMA0DA = U1TXBUF_;                        // Dst = UART TX Buffer
  DMA0SZ = 0x10;                            // Block size
  DMA0CTL = DMASRCINCR_3 + DMASBDB + DMALEVEL; // inc src, enable

// Record
  DMA1SA = U1RXBUF_;                        // Src address = UART RX Buffer
  DMA1DA = 0x220;                           // Dst address = RAM memory
  DMA1SZ = 0x10;                            // Size in bytes
  DMA1CTL = DMADSTINCR_3 + DMASBDB + DMAIE + DMAEN; // Sng, config

  _BIS_SR(LPM3_bits + GIE);                 // Enter LPM3 w/ interrupt
}

// DMA interrupt service routine
#pragma vector=DACDMA_VECTOR
__interrupt void DACDMA_ISR (void)
{
  DMA1CTL &= ~DMAIFG;                       // Clear DMA1 interrupt flag
  DMA0CTL |= DMAEN;                         // Enable
  DMA1CTL |= DMAEN;                         // (re)Enable
}