我想使用MSP430F4270加一个32.768HZ的低频晶振 但是找不到管脚接口。我查了F169系列的都有。 如果没有我怎么让看门狗的复位时间变长,比如变为5S
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我想使用MSP430F4270加一个32.768HZ的低频晶振 但是找不到管脚接口。我查了F169系列的都有。 如果没有我怎么让看门狗的复位时间变长,比如变为5S
qiang xue 说:看到选择模式了,配置倍频的寄存器是哪一些 能不能给一个例程。
//******************************************************************************
// MSP430x42x0 Demo - FLL+, Runs Internal DCO at 8MHz
//
// Description: This program demonstrates setting the internal DCO to run at
// 8MHz with auto-calibration by the FLL+.
// ACLK = LFXT1 = 32768, MCLK = SMCLK = DCOCLK = (121+1) x 2 x ACLK = 7995392Hz
// //* An external watch crystal between XIN & XOUT is required for ACLK *//
//
// MSP430F4270
// -----------------
// /|\| XIN|-
// | | | 32kHz
// --|RST XOUT|-
// | |
// | P1.1/MCLK|--> MCLK = 8Mhz
// | |
// | P1.5/ACLK|--> ACLK = 32kHz
// | |
//
// L. Westlund / S. Karthikeyan
// Texas Instruments Inc.
// June 2005
// Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.30A
//*****************************************************************************
#include <msp430.h>
int main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
SCFI0 |= FN_3; // Set DCO operating range
SCFQCTL = 121; // (121+1) x 32768 x 2 = 7.99 Mhz
FLL_CTL0 = DCOPLUS + XCAP14PF; // DCO+ set so freq = xtal x D x N+1
P1DIR = 0x22; // P1.1,5 to output direction
P1SEL = 0x22; // P1.1,5 to output MCLK & ACLK
while(1); // Loop in place
}
WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer SCFI0 |= FN_3; // Set DCO operating range SCFQCTL = 121; // (121+1) x 32768 x 2 = 7.99 Mhz FLL_CTL0 = DCOPLUS + XCAP14PF; // DCO+ set so freq = xtal x D x N+1qiang xue 说:WDTCTL = WDTPW + WDTHOLD;// Stop watchdog timerSCFI0 |= FN_3;// Set DCO operating rangeSCFQCTL = 121;// (121+1) x 32768 x 2 = 7.99 MhzFLL_CTL0 = DCOPLUS + XCAP14PF;// DCO+ set so freq = xtal x D x N+1也就是说只需要配置前面几条语句就可以使用32.768KHz倍频到8M频率了 是不是这个意思
是的