大家好,请教关于FR4133 DCO问题
以前MSP430G2xxx系列内部的DCO出厂的时候有校准,校准参数存在information memory里面,FR4133没有同样的机制吗?找了好久没看到有关于FR4133 DCO校准的说明。谢谢!
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大家好,请教关于FR4133 DCO问题
以前MSP430G2xxx系列内部的DCO出厂的时候有校准,校准参数存在information memory里面,FR4133没有同样的机制吗?找了好久没看到有关于FR4133 DCO校准的说明。谢谢!
4133 是通过寄存器手动设置。参考如下范例代码:
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//******************************************************************************
// MSP430FR413x Demo - Configure MCLK for 8MHz sourced from DCO.
//
// Description: Default DCODIV is MCLK and SMCLK source.
// By default, FR413x select XT1 as FLL reference.
// If XT1 is present, the XIN and XOUT pin needs to configure.
// If XT1 is absent, switch to select REFO as FLL reference automatically.
// XT1 is considered to be absent in this example.
// f(DCOCLK) = 2^FLLD * (FLLN+1) * (fFLLREFCLK / n).
// FLLD = 0, FLLN =243, n=1, DIVM =1, f(DCOCLK) = 2^0 * (243+1)*32768Hz = 8MHz,
// f(DCODIV) = (243+1)*32768Hz = 8MHz,
// ACLK = default REFO ~32768Hz, SMCLK = MCLK = f(DCODIV) = 8MHz.
// Toggle LED to indicate that the program is running.
//
// MSP430FR4133
// ---------------
// /|\| |
// | | |
// --|RST |
// | P1.0 |---> LED
// | P1.4 |---> MCLK = 8MHz
// | P8.0 |---> SMCLK = 8MHz
// | P8.1 |---> ACLK = 32768Hz
//
//
// William Goh
// Texas Instruments Inc.
// March 2014
// Built with IAR Embedded Workbench v6.10 & Code Composer Studio v6.0
//******************************************************************************
#include <msp430.h>
int main(void)
{
WDTCTL = WDTPW | WDTHOLD; // Stop watchdog timer
__bis_SR_register(SCG0); // disable FLL
CSCTL3 |= SELREF__REFOCLK; // Set REFO as FLL reference source
CSCTL0 = 0; // clear DCO and MOD registers
CSCTL1 &= ~(DCORSEL_7); // Clear DCO frequency select bits first
CSCTL1 |= DCORSEL_3; // Set DCO = 8MHz
CSCTL2 = FLLD_0 + 243; // DCODIV = 8MHz
__delay_cycles(3);
__bic_SR_register(SCG0); // enable FLL
while(CSCTL7 & (FLLUNLOCK0 | FLLUNLOCK1)); // Poll until FLL is locked
CSCTL4 = SELMS__DCOCLKDIV | SELA__REFOCLK; // set default REFO(~32768Hz) as ACLK source, ACLK = 32768Hz
// default DCODIV as MCLK and SMCLK source
P1DIR |= BIT0 | BIT4; // set MCLK and LED pin as output
P1SEL0 |= BIT4; // set MCLK pin as second function
P8DIR |= BIT0 | BIT1; // set ACLK and SMCLK pin as output
P8SEL0 |= BIT0 | BIT1; // set ACLK and SMCLK pin as second function
PM5CTL0 &= ~LOCKLPM5; // Disable the GPIO power-on default high-impedance mode
// to activate previously configured port settings
while(1)
{
P1OUT ^= BIT0; // Toggle P1.0 using exclusive-OR
__delay_cycles(10000000); // Delay for 10000000*(1/MCLK)=1.25s
}
}