MSP430 P1.1 P1.2 P1.3 第二功能
发布时间：2008-10-22 22:33
发布者：MSP430
关键词：
MSP430
| 定时器A在UP模式、CONTINUE 模式、UP/DOWN模式下，不利用中断程序即可在P1.1 P1.2 P1.3 管脚上输出所设定值的频率，并且在UP/DOWN模式下时，频率计算与前两种模式下不同，因为UP/DOWN模式下，CCIFG 是在TACCRX-1到TACCRX变化时，置1的，而TAIFG是在1到0置1的、 例程序： //****************************************************************************** // MSP-FET430P140 Demo - Timer_A, Toggle P1.1/TA0, Up Mode, DCO SMCLK // // Description: Toggle P1.1 using hardware TA0 output. Timer_A is configured // for up mode with CCR0 defining period, TA0 also output on P1.1. In this // example, CCR0 is loaded with 500-1 and TA0 will toggle P1.1 at TACLK/500. // Thus the output frequency on P1.1 will be the TACLK/1000. No CPU or // software resources required. // As coded with TACLK = SMCLK, P1.1 output frequency is ~800000/1000. // SMCLK = MCLK = TACLK = default DCO ~800kHz // // MSP430F149 // ----------------- // /|\| XIN|- // | | | // --|RST XOUT|- // | | // | P1.1/TA0|--> SMCLK/1000 // // M. Buccini // Texas Instruments Inc. // Feb 2005 // Built with IAR Embedded Workbench Version: 3.21A //修改时间:2008.8.20 am 8:13 // only timera 依靠DCO工作，而CPU 停止工作。 //****************************************************************************** #include void main(void) { WDTCTL = WDTPW + WDTHOLD; // Stop WDT P1DIR |= 0x02; // P1.1 output P1SEL |= 0x02; // P1.1 option select CCTL0 = OUTMOD_4; // CCR0 toggle mode CCR0 = 500-1; TACTL = TASSEL_2 + MC_1; // SMCLK, upmode _BIS_SR(CPUOFF); // CPU off } //****************************************************************************** // MSP-FET430P140 Demo - Timer_A, Toggle P1.1/TA0, Up/Down Mode, 32kHz ACLK // // Description: Toggle P1.1 using hardware TA0 output. Timer_A is configured // for up/down mode with CCR0 defining period, TA0 also output on P1.1. In // this example, CCR0 is loaded with 5 and TA0 will toggle P1.1 at TACLK/2*5. // Thus the output frequency on P1.1 will be the TACLK/20. No CPU or software 此处的说明与DATASHEET中的图不符合，并且DATASHEET中的图不是太懂 // resources required. Normal operating mode is LPM3. // As coded with TACLK = ACLK, P1.1 output frequency = 32768/20 = 1.6384kHz // ACLK = TACLK = 32kHz, MCLK = default DCO ~800kHz // //* External watch crystal installed on XIN XOUT is required for ACLK *// // // MSP430F149 // ----------------- // /|\| XIN|- // | | | 32kHz // --|RST XOUT|- // | | // | P1.1|-->TA0 ACLK/20 // // M. Buccini // Texas Instruments Inc. // Feb 2005 // Built with IAR Embedded Workbench Version: 3.21A //****************************************************************************** #include void main(void) { WDTCTL = WDTPW + WDTHOLD; // Stop WDT P1DIR |= 0x02; // P1.1 output P1SEL |= 0x02; // P1.1 option select CCTL0 = OUTMOD_4; // CCR0 toggle mode CCR0 = 5; TACTL = TASSEL_1 + MC_3; // ACLK, up-downmode _BIS_SR(LPM3_bits); // Enter LPM3 } |
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