6.6.1 OSC and PLL Block
Figure 6-30 shows the OSC and PLL block.
Figure 6-30 OSC and PLL Block Diagram
The on-chip oscillator circuit enables a crystal/resonator to be attached to the 2833x/2823x devices using the X1 and X2 pins. If the on-chip oscillator is not used, an external oscillator can be used in either one of the following configurations:
- A 3.3-V external oscillator can be directly connected to the XCLKIN pin. The X2 pin should be left unconnected and the X1 pin tied low. The logic-high level in this case should not exceed VDDIO.
- A 1.9-V (1.8-V for 100 MHz devices) external oscillator can be directly connected to the X1 pin. The X2 pin should be left unconnected and the XCLKIN pin tied low. The logic-high level in this case should not exceed VDD.
The three possible input-clock configurations are shown in Figure 6-31 to Figure 6-33.
Figure 6-31 Using a 3.3-V External Oscillator
Figure 6-32 Using a 1.9-V External Oscillator
Figure 6-33 Using the Internal Oscillator