dsp c5517 看门狗的时钟的选择及如何设置喂狗的时间？

（1）是的，Timer2配置为Watchdog模式。

（2）有counter, period寄存器计数。

（3） 14.3.2 Watchdog Timer Operation里有喂狗说明。
http://www.ti.com/lit/ug/spruh16b/spruh16b.pdf

CSL里有例程。 

我知道是count period寄存器，是如何计算的？就是对应时间计算公式是什么啊？具体呗

counter*period

是的。

您好 我测试了  发现counter计数器设置的大小与看门狗的时间无关，只与prescale有关 而且还是prescale+1的关系。  

/* Watchdog timer Object structure */
CSL_WdtObj wdtObj;
CSL_Status status;
CSL_WdtHandle hWdt = NULL;
WDTIM_Config hwConfig,getConfig;

T2INSR=0x0006; //选择时钟

/* Open the WDTIM module */
hWdt = (CSL_WdtObj *)WDTIM_open(WDT_INST_0, &wdtObj, &status);
if(NULL == hWdt)
{
UART_Str("WDTIM: Open for the watchdog Failed\n");
}
else
{
UART_Str("WDTIM: Open for the watchdog Passed\n");
}

hwConfig.counter = 12000; //开始值0xFFFF
hwConfig.prescale = 1; //预分频寄存器0x0FFF

/* Configure the watch dog timer */
status = WDTIM_config(hWdt, &hwConfig);
if(CSL_SOK != status)
{
UART_Str("WDTIM: Config for the watchdog Failed\n");
}
else
{
UART_Str("WDTIM: Config for the watchdog Passed\n");
}

/* Read the configured values */
status = WDTIM_getConfig(hWdt, &getConfig);
if(CSL_SOK != status)
{
UART_Str("WDTIM: Get Config for the watchdog Failed\n");
}
else
{
UART_Str("WDTIM: Get Config for the watchdog Passed\n");
}

/* Verify the configurations */
if((hwConfig.counter != getConfig.counter)||(hwConfig.prescale != getConfig.prescale))
{
UART_Str("WDTIM: Get and Set Configuration Mis-Matched \n");
}
else
{
UART_Str("WDTIM: Get and Set Configuration Matched \n");
}

/* Start the watch dog timer */
status = WDTIM_start(hWdt);

counter怎么会没用呢？

手册里写的The combination of the 16-bit counter with the 16-bit prescaler allows for a maximum countdown value of 4,294,967,296.