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AR# 64936

U-Boot - How Do I Set the PS_CLK Frequency?

Description

My Zynq-based system uses a PS_CLK frequency of something other than 33.333MHz (the default).

How do I configured U-Boot to use my frequency rather than the default?

Solution

The default value for the parameter CONFIG_ZYNQ_PS_CLK_FREQ is 33333333UL in u-boot-xlnx-xilinx\arch\arm\cpu\armv7\zynq\clk.c.

Because the zc70x board defaults use a ps_clk of 33.3MHz (the default), the board configuration file does not define this parameter. 

When using a PS_CLK other than 33.333MHz (for example, 50 MHz), the CONFIG_ZYNQ_PS_CLK_FREQ parameter should be redefined in the custom boards configuration header file.

Board configuration header files are found in u-boot-xlnx-xilinx\include\configs\.

AR# 64936
Date Created 07/08/2015
Last Updated 07/14/2015
Status Active
Type General Article
Devices
  • Zynq-7000