SLAU893B October 2023 – July 2024 MSPM0C1103 , MSPM0C1103-Q1 , MSPM0C1104 , MSPM0C1104-Q1
The WWDT must be enabled before being configured for use through the PWREN register (see peripheral power enable).
The WWDT is configured through the WWDTCTL0 and WWDTCTL1 registers. The registers are password protected. Any register access (read or write) must be a 32-bit access. Write access must also include the corresponding password in the most significant byte (0xC9 for WWDTCTL0, and 0xBE for WWDTCTL1). Attempting a register write without the correct password, or attempting a write with an access other than a 32-bit access generates a WWDT violation to SYSCTL. The password byte always reads as 0x00.
The WWDT is disabled and cleared after a SYSRST. The WWDTCTL0 register sets the static configuration of the WWDT, including: the clock divider, the timer period, the two closed window percentages, the timer mode (WWDT or interval), and the stop-in-sleep status. The first write (with a key match) to the WWDTCTL0 register enables the WWDT. Once the WWDT is enabled, the WWDTCTL0 register becomes write protected. Any attempt to write to the WWDTCTL0 register after the WWDT is enabled generates a WWDT violation to SYSCTL. The RUN bit in the WWDTSTAT register indicates that the WWDT is running.
Figure 16-2 shows the WWDT functional block diagram.