SLASFH8 March 2026 MSPM33C321A-Q1
ADVANCE INFORMATION
The RTC_A instance of the real-time clock operates off of a 32kHz input clock source (typically a low frequency crystal) and provides a time base to the application with multiple options for interrupts to the CPU. RTC_A provides common key features in relation to the Low-Frequency Subsystem (LFSS).
Common key features of RTC_A include:
Table 8-21 shows the RTC features supported in this device.
| RTC Features | RTC_A |
|---|---|
| Power enable register | - |
| Real-time clock and calendar mode providing seconds, minutes, hours, day of week, day of month, and year | Yes |
| Selectable binary or binary-coded decimal (BCD) format | Yes |
| Leap-year correction (valid for year 1901 through 2099) | Yes |
| Two customizable calendar alarm interrupts based on minute, hour, day of the week, and day of the month | Yes |
| Interval alarm interrupt to wake every minute, every hour, at midnight, or at noon | Yes |
| Periodic interrupt to wake at 4096, 2048, 1024, 512, 256, or 128Hz | Yes |
| Periodic interrupt to wake at 64, 32, 16, 8, 4, 2, 1, and 0.5Hz | Yes |
| Interrupt capability down to STANDBY mode with STOPCLKSTBY | Yes |
| Calibration for crystal offset error and crystal temperature drift (up to ±240ppm total) | Yes |
| RTC clock output to pin for calibration (GPIO) | Yes |
| RTC clock output to pin for calibration (TIO) | Yes |
| Three bit prescaler for heartbeat function with interrupt generation | Yes |
| RTC external clock selection of untrimmed 32kHz, trimmed 512Hz, 256Hz or 1Hz | Yes |
RTC time stamp capture upon detection of a timer stamp
event, including:
|
Yes |
| RTC counter lock function | Yes |
For more details, see the RTC chapter of the MSPM33C3x 160-MHz Microcontrollers Technical Reference Manual.