Module Overview

The AST module in the SAM4L devices is a 32-bit counter, with a 32-bit programmable prescaler. Typically, the AST clock is run continuously, including in the device's low-power sleep modes, to track the current time and date information. The AST can also wake-up the system from backup mode using either the alarm wakeup, periodic wakeup, or overflow wake-up mechanisms.

The AST has been designed to meet the system tick and Real-Time Clock requirements of most embedded operating systems.

In this driver, the AST is operated in Calendar Mode. This allows for an easy integration of a Real-Time Clock and calendar into a user application to track the passing of time and/or perform scheduled tasks.

Whilst operating in Calendar Mode, the AST features: