71.3 PHY Setup Procedure

The reference clock accepts 16, 20, 24 and 32 MHz main crystal input frequencies.

To start USB operations, apply the following sequence:
  1. Enable the main crystal in PMC_MOR.
  2. Set the main crystal frequency in PMC_XTALF to define the multiplier.
  3. Release PHY reset in RSTC_GRSTR for each PHY (A, B, C) to be used.
  4. Wait for 45 µs before any USB operation.
Figure 71-1. USB 2.0 PHY Clock Generation for Each USB Transceiver