2.4 Buffer Types
| Buffer | Description |
|---|---|
| AIO | Analog bi-directional |
| ICLK | Crystal or reference clock oscillator input |
| OCLK | Crystal output |
| PD |
55 kΩ (typical) internal pull-down. Unless otherwise noted in the pin description, internal pull-downs are not enabled. Internal pull-down resistors prevent unconnected inputs from floating. Do not rely on internal resistors to drive signals external to the device. When connected to a load that must be pulled low, an external resistor must be added. |
| PU |
55 kΩ (typical) internal pull-up. Unless otherwise noted in the pin description, internal pull-ups are not enabled. Internal pull-up resistors prevent unconnected inputs from floating. Do not rely on internal resistors to drive signals external to the device. When connected to a load that must be pulled high, an external resistor must be added. |
| VI-VDDAU | 3.3V input (VDDAU power domain) |
| VIS-VDDP | 3.3V Schmitt-triggered input (VDDP power domain) |
| VO-VDDP | 3.3V output with configurable output drive (VDDP power domain) |
| VOH-VDDP | 3.3V high-speed output with configurable output drive (VDDP power domain) |
| VODL-VDDP | 3.3V n-channel open-drain sink output drive (VDDP power domain) |
| VODH-VDDAU | 3.3V p-channel open-drain source output drive (VDDAU power domain) |