SPRUJ86C October 2023 – August 2024 AM263P2 , AM263P4 , AM263P4-Q1
The AM263Px SoC requires a 25MHz clock input for XTAL_XI. All reference clocks required for the SoC and the three Ethernet PHY's are generated from a single four output clock buffer (LMK1C1103PWR), which is sourced from a single 25MHz LVCMOS Oscillator by default. A clock buffer is used for level translation from 3.3V to 1.8V.
The Control Card also requires a 16MHz clock source for the TM4C129 microcontroller for UART-USB JTAG support.
Alternatively, the SoC clock input can be sourced from a single 25MHz crystal. To use the crystal there must be resistors mounted and unmounted. When the crystal is used as a clock source then the AM263Px CLKOUT0 signal is used to source the four output clock buffer for the Ethernet PHY reference clock signals.
The following table describes the proper resistors to be mounted and DNI'd for each clock source configuration.
Clock Source | Mounted | DNI |
---|---|---|
25MHz LVCMOS Oscillator (default) | R273, R176 | R178, R179, R271 |
25MHz Crystal | R178, R179, R271 | R273, R176 |