33.20.1 Main System Bus Clock Switching Timings
The following tables give the worst case timings required for the Main System Bus clock to switch from one selected clock to another one. This is in the event that the prescaler is deactivated. When the prescaler is activated, an additional time of 64 clock cycles of the new selected clock has to be added.
| To | From | ||
|---|---|---|---|
| Main Clock | TD_SLCK | PLL Clock | |
| Main Clock | – | 4 × TD_SLCK + 2.5 × Main Clock | 3 × PLL Clock + 4 × TD_SLCK + 1 × Main Clock |
| TD_SLCK | 0.5 × Main Clock + 4.5 × TD_SLCK | – | 3 × PLL Clock + 5 × TD_SLCK |
| PLL Clock | 0.5 × Main Clock + 4 × TD_SLCK + PLLCOUNT × TD_SLCK + 2.5 × PLL Clock | 2.5 × PLL Clock + 5 × TD_SLCK + PLLCOUNT × TD_SLCK | 2.5 × PLL Clock + 4 × TD_SLCK + PLLCOUNT × TD_SLCK |
Note: PLL designates either the PLLA or the UPLL Clock. PLLCOUNT designates either PLLACOUNT
or UPLLCOUNT.
| To | From | |
|---|---|---|
| PLLA Clock | UPLL Clock | |
| PLLA Clock | 2.5 × PLLA Clock + 4 × TD_SLCK + PLLACOUNT × TD_SLCK | 3 × PLLA Clock + 4 × TD_SLCK + 1.5 × PLLA Clock |
| UPLL Clock | 3 × UPLL Clock + 4 × TD_SLCK + 1.5 × UPLL Clock | 2.5 × UPLL Clock + 4 × TD_SLCK + UPLLCOUNT × TD_SLCK |