24.5 Register Description
Some peripherals include module enable bits internally. The PMD bit is used for clock gating of the PBx_CLK and GCLK for all peripherals. If the peripheral also includes the internal enable bit, the PMD bit and internal enable Configuration bit must be configured by software for that peripheral.
The following table summarizes each peripheral's enable and disable controls. For more details on the internal enable/disable control, see Peripheral Access Controller (PAC) from Related Links.
| Module | PMD Control | Module Control | Enable/Disable Strategy |
|---|---|---|---|
| AC | Present | Present | Disable at PMD or Module |
| ADC | Present | Present | Disable at PMD or Module |
| CCL | NA | Present | Disable at Module |
| CVD | Present | Present | Disable at PMD or Module |
| CMCC | NA | Present | Disable at Module |
| DMAC | NA | Present | Disable at Module |
| DSU | NA | NA | Always Enabled (Dynamic ON/OFF) |
| EIC | NA | Present | Disable at Module |
| EVSYS | NA | NA | Always Enabled (Dynamic ON/OFF) |
| FREQM | NA | Present | Disable at Module |
| PAC | NA | NA | Always Enabled (Dynamic ON/OFF) |
| RAMECC | NA | NA | Disabled by default |
| SERCOM | Present | Present based on VSEL | Disable at PMD or Module |
| TC | Present | Present | Disable at PMD or Module |
| TCC | Present | Present | Disable at PMD or Module |
| CANn | Present | Present based on VSEL | Disable at PMD or Module |
| USB | Present | Present based on VSEL | Disable at PMD or Module |
| ETH | Present | Present based on VSEL | Disable at PMD or Module |
| ADCSARHR | Present | Present | Disable at PMD or Module |
| ADCSAR | Present | Present | Disable at PMD or Module |
| DAC | Present | Present | Disable at PMD or Module |
| QEI | Present | Present | Disable at PMD or Module |
Note: For modules with both PMD control and Module
control, Enable = PMDx =
0 AND Module Enable = 1, Disable
= PMDx = 1 OR Module Enable = 0.