430 header file explanation

{

  unsigned short WDTCTL; /* Watchdog Timer Control */

  struct

  {

    unsigned short WDTIS0 : 1; /* */

    unsigned short WDTIS1 : 1; /* */

    unsigned short WDTSSEL : 1; /* */

    unsigned short WDTCNTCL : 1; /* */

    unsigned short WDTTMSEL : 1; /* */

    unsigned short WDTNMI : 1; /* */

    unsigned short WDTNMIES : 1; /* */

    unsigned short WDTHOLD : 1; /* */

  }WDTCTL_bit;

} @0x0120;

enum {

  WDTIS0 = 0x0001,

  WDTIS1 = 0x0002,

  WDTSSEL = 0x0004,

  WDTCNTCL = 0x0008,

  WDTTMSEL = 0x0010,

  WDTNMI = 0x0020,

  WDTNMIES = 0x0040,

  WDTHOLD = 0x0080

};

The address unit of WDTCTL is 0x0120. What does the following paragraph mean? Commonwealth?

unsigned short WDTIS0 : 1; // 1 represents the field width (binary), which means WDTISO is either 1 or 0

The latter 8 bits share the memory unit with WDTCTL. Looking at the user guide, WDTCTL is a 16-bit register, WDTIS0 is located at bit0, and so on, WDTHOLD is bit7, and these bits are all 0 after reset. In MSP's C language, bit variables are not supported. In the IO header file of 430, bit variable access to registers is implemented in this way of definition.

WDTCTL=WDTPW+WDTHOLD; // Stop watchdog. How to explain this operation of stopping watchdog?

WDTCTL is obviously a watchdog control register, and WDTPW is a macro definition. The header file looks like this, #define WDTPW (0x5A00u). In the user guide, WDTCTL is a 16-bit register, and the names of bit15-bit8 are WDTPW, must be written as 0x5a, these 8 bits must be initialized to 0x5a. This sentence completes the initialization of WDTPW and sets WDTHOLD. The result of setting WDTHOLD is that the watchdog timer stops.

unsigned short WDTNMIES : 1; // Watchdog timer non-maskable interrupt edge selection bit.

unsigned short WDTNMI : 1; // Watchdog timer non-maskable interrupt selection

unsigned short WDTTMSEL : 1; //Watchdog timer mode selection

unsigned short WDTCNTCL : 1; // Watchdog timer counter clear selection bit

unsigned short WDTSSEL : 1; //Watchdog timer clock source selection

unsigned short WDTIS0 : 1; // Watchdog time interval selection

unsigned short WDTIS1 : 1; // time interval selection

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