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/* --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,
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*
*******************************************************************************
*
* 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--*/
//******************************************************************************
// MSP430F552x Demo - USCI_A0, 115200 UART Echo ISR, DCO SMCLK
//
// Description: Echo a received character, RX ISR used. Normal mode is LPM0.
// USCI_A0 RX interrupt triggers TX Echo.
// Baud rate divider with 1048576hz = 1048576/115200 = ~9.1 (009h|01h)
// ACLK = REFO = ~32768Hz, MCLK = SMCLK = default DCO = 32 x ACLK = 1048576Hz
// See User Guide for baud rate divider table
//
// MSP430F552x
// -----------------
// /|\| |
// | | |
// --|RST |
// | |
// | P3.3/UCA0TXD|------------>
// | | 115200 - 8N1
// | P3.4/UCA0RXD|<------------
//
// Bhargavi Nisarga
// Texas Instruments Inc.
// April 2009
// Built with CCSv4 and IAR Embedded Workbench Version: 4.21
//******************************************************************************
#include <msp430.h>
int main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
P3SEL |= BIT3+BIT4; // P3.3,4 = USCI_A0 TXD/RXD
UCA0CTL1 |= UCSWRST; // **Put state machine in reset**
UCA0CTL1 |= UCSSEL_2; // SMCLK
UCA0BR0 = 9; // 1MHz 115200 (see User's Guide)
UCA0BR1 = 0; // 1MHz 115200
UCA0MCTL |= UCBRS_1 + UCBRF_0; // Modulation UCBRSx=1, UCBRFx=0
UCA0CTL1 &= ~UCSWRST; // **Initialize USCI state machine**
UCA0IE |= UCRXIE; // Enable USCI_A0 RX interrupt
__bis_SR_register(LPM0_bits + GIE); // Enter LPM0, interrupts enabled
__no_operation(); // For debugger
}
// Echo back RXed character, confirm TX buffer is ready first
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=USCI_A0_VECTOR
__interrupt void USCI_A0_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(USCI_A0_VECTOR))) USCI_A0_ISR (void)
#else
#error Compiler not supported!
#endif
{
switch(__even_in_range(UCA0IV,4))
{
case 0:break; // Vector 0 - no interrupt
case 2: // Vector 2 - RXIFG
while (!(UCA0IFG&UCTXIFG)); // USCI_A0 TX buffer ready?
UCA0TXBUF = UCA0RXBUF; // TX -> RXed character
break;
case 4:break; // Vector 4 - TXIFG
default: break;
}
}
