MSP430FR5994时钟和波特率问题

MSP430FR5994 LFXIN和LFOUT之间结论一个32768Hz的晶振

串口初始化代码如下：

param.selectClockSource = EUSCI_A_UART_CLOCKSOURCE_SMCLK;
param.clockPrescalar = 52;
param.firstModReg = 1;
param.secondModReg = 0x49;
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_OVERSAMPLING_BAUDRATE_GENERATION;

波特率是多少？怎么计算出来的？