97 lines
4.3 KiB
C
Executable File
97 lines
4.3 KiB
C
Executable File
/* --COPYRIGHT--,BSD_EX
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* Copyright (c) 2012, Texas Instruments Incorporated
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* * Neither the name of Texas Instruments Incorporated nor the names of
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* its contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*******************************************************************************
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*
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* MSP430 CODE EXAMPLE DISCLAIMER
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*
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* MSP430 code examples are self-contained low-level programs that typically
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* demonstrate a single peripheral function or device feature in a highly
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* concise manner. For this the code may rely on the device's power-on default
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* register values and settings such as the clock configuration and care must
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* be taken when combining code from several examples to avoid potential side
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* effects. Also see www.ti.com/grace for a GUI- and www.ti.com/msp430ware
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* for an API functional library-approach to peripheral configuration.
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*
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* --/COPYRIGHT--*/
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//******************************************************************************
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// MSP430F20xx Demo - USICNT Used as a One-Shot Timer Function, DCO SMCLK
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//
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// Description: USI conunter is used as a one-shot timer. The USI
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// conunter ISR toggles P1.0 using software. As coded ACLK is pre-divided by
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// 128 and the USICNT loaded with 32, for a total divided of 4096 or
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// 12-bits. USICNT must be reloaded after each interrupt which also clears
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// interrupt flag.
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// ACLK = VLO, MCLK = SMCLK = default DCO
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//
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// MSP430F20xx
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// -----------------
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// /|\| XIN|-
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// | | |
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// --|RST XOUT|-
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// | |
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// | P1.0|-->LED
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//
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// M. Buccini / L. Westlund
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// Texas Instruments Inc.
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// September 2005
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// Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.40A
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//******************************************************************************
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#include <msp430.h>
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int main(void)
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{
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WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
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BCSCTL3 |= LFXT1S_2; // ACLK = VLO
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P1DIR |= 0x01; // Set P1.0 to output direction
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USICTL0 |= USIMST; // Master mode
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USICTL1 |= USIIE; // Counter interrupt, flag remains set
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USICKCTL = USIDIV_7 + USISSEL_1; // /128 ACLK
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USICTL0 &= ~USISWRST; // USI released for operation
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__bis_SR_register(LPM3_bits + GIE); // Enter LPM3 w/ interrupt
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}
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// USI interrupt service routine
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#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
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#pragma vector=USI_VECTOR
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__interrupt void universal_serial_interface(void)
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#elif defined(__GNUC__)
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void __attribute__ ((interrupt(USI_VECTOR))) universal_serial_interface (void)
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#else
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#error Compiler not supported!
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#endif
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{
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P1OUT ^= 0x01; // Toggle P1.0 using exclusive-OR
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USICNT = 0x1F; // re-load counter
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}
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