Various external clock inputs/outputs are needed to drive the device. Summary of these input clock signals is as follows:

• OSC1_XO/OSC1_XI — Еxternal main crystal interface pins connected to internal oscillator which sources reference clock and provides reference clock to PLLs within MAIN domain. Also, for audio applications, high-frequency oscillator 0 is used to provide audio clock frequencies to MCASPs.
• High frequency oscillators inputs
  • OSC1_XO/OSC1_XI — external main crystal interface pins connected to internal oscillator which sources reference clock. Provides reference clock to PLLs within MAIN domain. This highfrequency oscillator is used to provide audio clock frequencies to MCASPs.
  • WKUP_OSC0_XO/WKUP_OSC0_XI — external main crystal interface pins of the internal oscillator which sources a reference clock. Provides reference clock to PLLs within WKUP/MCU and MAIN domain.
• Low frequency oscillator input
  • WKUP_LF_CLKIN — External 32.768 kHz clock input.
• General purpose clock inputs
  • MCU_EXT_REFCLK0 — optional external. Provides system clock input (MCU domain).
  • EXT_REFCLK1 — optional external system clock input (MAIN domain). Optionally PLL2 (PER1) and MCASP can be sourced by EXT_REFCLK1 (sourced externally).
  • SERDES0_REFCLK_P/N — SerDes reference clock input for PCIe or Optional USB3 and SGMII interfaces.
• External CPTS reference clock inputs
  • MCU_CPTS0_RFT_CLK — CPTS reference clock inputs for MCU_CPTS_RFT_CLK.
  • CPTS0_RFT_CLK — CPTS reference clock inputs for CPTS_RFT_CLK.
• External audio reference clock input/output pins
  • AUDIO_EXT_REFCLK0
  • AUDIO_EXT_REFCLK1

Figure 7-23 shows the external input clock sources and the output clocks to peripherals.

Figure 7-23 Input Clocks Interface

For more information about Input clock interfaces, see Clocking section in Device Configuration chapter in the device TRM.