5.9.3.8 Output Clocks
The device provides several system clock outputs. Summary of these output clock outputs are as follows:
- CLKOUT
- CLKOUT port provides an option to output 50 MHz or 25 MHz clock. This clock can be used as a reference clock for RMII or MII Ethernet companion devices.
- SYSCLKOUT
- SYSCLKOUT is an LVCMOS clock output of the internal clock SYSCLK1 which has been divided by 6. This output is provided for test and debug purposes only. Performance of this output is not defined due to many complex combinations of system variables. For example, this output is being sourced from the Main PLL supporting many configuration options that yield various levels of performance. There are also other unpredictable contributors to performance such as application specific noise or crosstalk which may couple into the clock circuits. Therefore, there are no plans to specify performance for this output.
- OBSCLK
- OBSCLK_N / OBSCLK_P is an LVDS clock output that can be configured to observe one of 9 internal clocks. This output is provided for test and debug purposes only. Performance of this output is not defined due to many complex combinations of system variables. For example, this output may be sourced from several PLLs with each PLL supporting many configuration options that yield various levels of performance. There are also other unpredictable contributors to performance such as application specific noise or crosstalk which may couple into the clock circuits. Therefore, there are no plans to specify performance for this output.