MSP430FR2433: 使用DCO时，是否需要对DCOFFG进行处理？

使用eusci_a_uart_ex1_loopbackAdvanced例程，学习MSP430FR2433的时钟，在debug模式下运行一段时间暂停，看到的关于CS模块的寄存器如下：

片子运行时钟SMCLK = MCLK = BRCLK = DCOCLKDIV = ~1MHz, ACLK = 32.768kHz；

即这里使用了DCO作为SMCLK的时钟源，又使用SMCLK作为波特率的时钟源，但是在初始化的时候并未对DCO进行配置；

但实际上DCOFFG显示是有错误的，这里不需要对该错误进行处理吗？

附main.c中的代码：

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//******************************************************************************
//!  EUSCI_A0 External Loopback test using EUSCI_A_UART_init API
//!
//!  Description: This demo connects TX to RX of the MSP430 UART
//!  The example code shows proper initialization of registers
//!  and interrupts to receive and transmit data.
//!
//!  SMCLK = MCLK = BRCLK = DCOCLKDIV = ~1MHz, ACLK = 32.768kHz
//!
//!
//!Tested on MSP430FR4133
//!-----------------
//!RST -|P1.0/UCA0TXD|----|
//!|||
//!|||
//!|P1.1/UCA0RXD|----|
//!||
//!
//! This example uses the following peripherals and I/O signals.  You must
//! review these and change as needed for your own board:
//! - UART peripheral
//! - GPIO Port peripheral (for UART pins)
//! - UCA0TXD
//! - UCA0RXD
//!
//! This example uses the following interrupt handlers.  To use this example
//! in your own application you must add these interrupt handlers to your
//! vector table.
//! - USCI_A0_VECTOR.
//******************************************************************************
#include "driverlib.h"

uint16_t i;
uint8_t RXData = 0, TXData = 0;
uint8_t check = 0;
uint32_t clockValue;

void main(void)
{// stop watchdogWDT_A_hold(WDT_A_BASE);// XT1 Setup//Set P4.1 and P4.2 as Function Input./** Select Port 4* Set Pin 1, 2 to input Module Function, XT1.*/GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P2,GPIO_PIN0 + GPIO_PIN1,GPIO_PRIMARY_MODULE_FUNCTION);//Set external clock frequency to 32.768 KHzCS_setExternalClockSource(32768);//Set ACLK=XT1CS_initClockSignal(CS_ACLK,CS_XT1CLK_SELECT,CS_CLOCK_DIVIDER_1);//Start XT1 with no time outCS_turnOnXT1(CS_XT1_DRIVE_0);//Set SMCLK = DCO with frequency divider of 1CS_initClockSignal(CS_SMCLK,CS_DCOCLKDIV_SELECT,CS_CLOCK_DIVIDER_1);//Set MCLK = DCO with frequency divider of 1CS_initClockSignal(CS_MCLK,CS_DCOCLKDIV_SELECT,CS_CLOCK_DIVIDER_1);// Configure UART pins//Set P1.0 and P1.1 as Secondary Module Function Input./** Select Port 1* Set Pin 0, 1 to input with function, (UCA0TXD/UCA0SIMO, UCA0RXD/UCA0SOMI).*/GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P1,GPIO_PIN4 + GPIO_PIN5,GPIO_PRIMARY_MODULE_FUNCTION);/** Disable the GPIO power-on default high-impedance mode to activate* previously configured port settings*/PMM_unlockLPM5();//Configure UART//SMCLK = 1MHz, Baudrate = 115200//UCBRx = 8, UCBRFx = 0, UCBRSx = 0xD6, UCOS16 = 0EUSCI_A_UART_initParam param = {0};param.selectClockSource = EUSCI_A_UART_CLOCKSOURCE_SMCLK;param.clockPrescalar = 8;param.firstModReg = 0;param.secondModReg = 0xD6;param.parity = EUSCI_A_UART_NO_PARITY;param.msborLsbFirst = EUSCI_A_UART_LSB_FIRST;param.numberofStopBits = EUSCI_A_UART_ONE_STOP_BIT;param.uartMode = EUSCI_A_UART_MODE;param.overSampling = EUSCI_A_UART_LOW_FREQUENCY_BAUDRATE_GENERATION;if(STATUS_FAIL == EUSCI_A_UART_init(EUSCI_A0_BASE, &param)){return;}EUSCI_A_UART_enable(EUSCI_A0_BASE);EUSCI_A_UART_clearInterrupt(EUSCI_A0_BASE,EUSCI_A_UART_RECEIVE_INTERRUPT);// Enable USCI_A0 RX interruptEUSCI_A_UART_enableInterrupt(EUSCI_A0_BASE,EUSCI_A_UART_RECEIVE_INTERRUPT);// Enable interrupt//Verify if the Clock settings are as expectedclockValue = CS_getMCLK();clockValue = CS_getACLK();clockValue = CS_getSMCLK();__enable_interrupt();while(1){TXData = TXData + 1;// Increment TX data// Load data onto bufferEUSCI_A_UART_transmitData(EUSCI_A0_BASE,TXData);while(check != 1){;}check = 0;}
}

//******************************************************************************
//
//This is the USCI_A0 interrupt vector service routine.
//
//******************************************************************************
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=USCI_A0_VECTOR
__interrupt
#elif defined(__GNUC__)
__attribute__((interrupt(USCI_A0_VECTOR)))
#endif
void EUSCI_A0_ISR(void)
{switch(__even_in_range(UCA0IV,USCI_UART_UCTXCPTIFG)){case USCI_NONE: break;case USCI_UART_UCRXIFG:RXData = EUSCI_A_UART_receiveData(EUSCI_A0_BASE);if(!(RXData == TXData))// Check value{while(1){;}}check = 1;break;case USCI_UART_UCTXIFG: break;case USCI_UART_UCSTTIFG: break;case USCI_UART_UCTXCPTIFG: break;}
}

Cherry Zhou：

您好，我们已收到您的问题并升级到英文论坛，如有答复将尽快回复您。谢谢！

,

Cherry Zhou：

您好，您需要在代码中添加 DCO Software Trim routine：

,

ShineRoyal：

1. 我对eusci_a_uart_ex1_loopbackAdvanced例程没有做任何改动，且我是从main.c中line39的DCOCLKDIV = ~1MHz推断出启用了DCO；

2. 我想确定，这个例程有没有启用DCO？

3. 我想知道，如果是启用了DCO，不对DCO寄存器做配置可以直接用吗？即使DCOFFG显示有错误也不影响使用吗？

4. 我是基于这个例程的运行效果发表了我的疑惑，为什么需要我在代码中添加 DCO Software Trim routine呢？

,

Cherry Zhou：

您好，DCO 无需配置就可以使用。 不过我们不太建议这样做。 建议您先配置 DCO ，然后添加 DCO 软件修整例程（DCO software trim routine） 。