Good afternoon, I am working on a project and I am interested in utilizing the VLO to turn off and on the msp430fr2311 microcontroller. I found an example code in the documentation for doing this with an external 32khz crystal: /* --COPYRIGHT--,BSD_EX * Copyright (c) 2014, 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--*/ //****************************************************************************** // MSP430FR231x Demo - Enters LPM3 with ACLK = XT1CLK = 32768Hz. // // Description: Configures ACLK to be sourced from XT1 crystal. Enter LPM3 until // WDT ISR is executed and toggles the LED on P1.0. // // MSP430FR2311 // --------------- // /|\| | // | | | // | | XIN(P2.7)|-- // --|RST | ~32768Hz // | XOUT(P2.6)|-- // | | // | P1.0|-->LED // // Darren Lu // Texas Instruments Inc. // July 2015 // Built with IAR Embedded Workbench v6.30 & Code Composer Studio v6.1 //****************************************************************************** #include int main(void) { WDTCTL = WDT_ADLY_1000; // WDT 1000ms, ACLK, interval timer SFRIE1 |= WDTIE; // Enable WDT interrupt P2SEL1 |= BIT6 + BIT7; // P2.0: XOUT; P2.1: XI1 CSCTL4 = SELMS__DCOCLKDIV | SELA__XT1CLK; // MCLK=SMCLK=DCO; ACLK=XT1 // Port Configuration all un-used pins to output low P1OUT = 0x00; P2OUT = 0x00; P1DIR = 0xff; P2DIR = 0xff; // Disable the GPIO power-on default high-impedance mode // to activate previously configured port settings PM5CTL0 &= ~LOCKLPM5; do { CSCTL7 &= ~(XT1OFFG | DCOFFG); // Clear XT1 and DCO fault flag SFRIFG1 &= ~OFIFG; }while (SFRIFG1 & OFIFG); // Test oscillator fault flag __bis_SR_register(LPM3_bits | GIE); // Enter LPM3 __no_operation(); // For debug } // Watchdog Timer interrupt service routine #if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__) #pragma vector=WDT_VECTOR __interrupt void WDT_ISR(void) #elif defined(__GNUC__) void __attribute__ ((interrupt(WDT_VECTOR))) WDT_ISR (void) #else #error Compiler not supported! #endif { P1OUT ^= BIT0; // Toggle P1.0 (LED) every 1s } How could I edit the code to use the internal VLO as an ACLK source instead. Regards, George Fleming
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