SPRUJ63A September 2022 – October 2023
A clock generator of part number CDCLVC1310 is used to drive 25 MHz clock to the Ethernet PHYs. CDCLVC1310 is a 1:10 LVCMOS clock buffer, which takes 25 MHz crystal/LVCMOS reference input and provides ten 25 MHz LVCMOS clock outputs. The source for the clock buffer is either the CLKOUT0 pin from the SoC or a 25 MHz oscillator (ASFLMB-25.000MHZ-LY-T), the selection is made using a set of resistors. This selection can be made through the select lines of the clock buffer.
The resistor termination for single ended Crystal input is provided as per device-specific data sheet.
IN_SEL1 | IN_SEL0 | Clock Chosen | Mount | Unmount |
---|---|---|---|---|
0 | 0 | EXT_REFCLK from SoC | R40, R45 | R248, R253 |
1 | 0 | Oscillator input | R253, R40 | R45, R248 |