10.3.4.1 Power Management

The UDPHS is not continuously clocked.

To use the UDPHS, assuming the UTMI USB PLL is off and the UDPHS is disabled:
  1. Enable the UDPHS clock in the Power Management Controller (PMC).
  2. Enable the UDPHS in the UDPHS_CTRL register (EN_UDPHS bit).
  3. Enable the UTMI (PLL and transceiver) by enabling the bandgap and then the voltage regulator in the PMC (UTMIBG and UTMIVR bits in the PMC_PLL_ACR register).
Note: If the application does not require UDPHS operations, the UDPHS clock can be stopped when not needed and restarted later.