Introduction RM0046
58/936 Doc ID 16912 Rev 5
1.6.10 Main oscillator
The main oscillator provides these features:
● Input frequency range: 4–40 MHz
● Crystal input mode or oscillator input mode
● PLL reference
1.6.11 Internal RC oscillator
This device has an RC ladder phase-shift oscillator. The architecture uses constant current
charging of a capacitor. The voltage at the capacitor is compared by the stable bandgap
reference voltage.
The RC oscillator provides these features:
● Nominal frequency 16 MHz
● ±5% variation over voltage and temperature after process trim
● Clock output of the RC oscillator serves as system clock source in case loss of lock or
loss of clock is detected by the PLL
● RC oscillator is used as the default system clock during startup
1.6.12 Periodic interrupt timer (PIT)
The PIT module implements these features:
● 4 general-purpose interrupt timers
● 32-bit counter resolution
● Clocked by system clock frequency
● Each channel usable as trigger for a DMA request
1.6.13 System timer module (STM)
The STM implements these features:
● One 32-bit up counter with 8-bit prescaler
● Four 32-bit compare channels
● Independent interrupt source for each channel
● Counter can be stopped in debug mode
1.6.14 Software watchdog timer (SWT)
The SWT has the following features:
● 32-bit time-out register to set the time-out period
● Programmable selection of window mode or regular servicing
● Programmable selection of reset or interrupt on an initial time-out
● Master access protection
● Hard and soft configuration lock bits
● Reset configuration inputs allow timer to be enabled out of reset