/* --COPYRIGHT--,BSD_EX
 * Copyright (c) 2012, Texas Instruments Incorporated
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * *  Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * *  Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * *  Neither the name of Texas Instruments Incorporated nor the names of
 *    its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *******************************************************************************
 * 
 *                       MSP430 CODE EXAMPLE DISCLAIMER
 *
 * MSP430 code examples are self-contained low-level programs that typically
 * demonstrate a single peripheral function or device feature in a highly
 * concise manner. For this the code may rely on the device's power-on default
 * register values and settings such as the clock configuration and care must
 * be taken when combining code from several examples to avoid potential side
 * effects. Also see www.ti.com/grace for a GUI- and www.ti.com/msp430ware
 * for an API functional library-approach to peripheral configuration.
 *
 * --/COPYRIGHT--*/
//******************************************************************************
//  MSP430F20x2/3 Demo - USI SPI Interface to TLC549 8-bit ADC
//
//   Description: This program demonstrates the USI in SPI mode interface to a
//   TLC549 8-bit ADC. If AIN > 0.5(REF+ - REF-), P1.0 set, else reset.
//   ACLK = n/a, MCLK = SMCLK = default DCO, UCICLK = SMCLK/4
//   //** VCC must be at least 3v for TLC549 **//
//
//                          MSP430F20x2/3
//                       -----------------
//                   /|\|              XIN|-
//        TLC549      | |                 |
//    -------------   --|RST          XOUT|-
//   |           CS|<---|P1.1             |
//   |      DATAOUT|--->|P1.7/SOMI    P1.0|-->LED
// ~>|AIN   I/O CLK|<---|P1.5/SCLK        |
//
//  M. Buccini / L. Westlund
//  Texas Instruments Inc.
//  October 2005
//  Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.40A
//******************************************************************************

#include <msp430.h>

int main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop watchdog timer
  P1OUT = 0;
  P1DIR |= 0x03;
  USICTL0 |= USIPE7 + USIPE5 + USIMST + USIOE; // Port, SPI master
  USICTL1 |= USIIE;                         // Counter interrupt, flag remains set
  USICKCTL = USIDIV_2 + USISSEL_2;          // /4 SMCLK
  USICTL0 &= ~USISWRST;                     // USI released for operation
  USICNT = 8;                               // init-load counter
  __bis_SR_register(LPM0_bits + GIE);       // Enter LPM0 w/ interrupt
}

// USI interrupt service routine
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=USI_VECTOR
__interrupt void universal_serial_interface(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(USI_VECTOR))) universal_serial_interface (void)
#else
#error Compiler not supported!
#endif
{
  P1OUT |= 0x02;                            // Disable TLC549
  if (USISRL > 0x7F)
    P1OUT |= 0x01;
  else
    P1OUT &= ~0x01;
  P1OUT &= ~0x02;                            // Enable TLC549
  USICNT = 8;                                // re-load counter
}