20.2.5 Performance Level

Performance level allows the user to adjust the regulator output voltage to reduce power consumption. The user can on the fly select the most suitable performance level, depending on the application demands.

The SAM device can operate at two different performance levels (PL0 and PL2). When operating at PL0, the voltage applied on the full logic area is reduced by voltage scaling. This voltage scaling technique allows to reduce the active power consumption while decreasing the maximum frequency of the device. When operating at PL2, the voltage regulator supplies the highest voltage, allowing the device to run at higher clock speeds.

Performance level transition is possible only when the device is in active mode. After a reset, the device starts at the lowest performance level (lowest power consumption and lowest max. frequency). The application can then switch to another performance level at any time without any stop in the code execution. As shown in Figure 20-1.

Note: When scaling down the performance level, the bus frequency should first be scaled down in order to not exceed the maximum frequency allowed for the low performance level. When scaling up the performance level (e.g. from PL0 to PL2), check the performance level status before increasing the bus frequency. It can be increased only when the performance level transition is completed.