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AR# 40302

13.1 EDK - XPS or AXI USB2 Device – ERROR:EDK - [axi/xps]_usb2_device_0 - can't use empty string as operand of "/"


The error below is received while trying to implement an AXI or XPS/PLB USB2 Device core in a design:

ERROR:EDK - [axi/xps]_usb2_device_0 ([axi/xps]_usb2_device) - can't use empty string as operand of "/"
ERROR:EDK:440 - platgen failed with errors!
make: *** [implementation/system.bmm] Error 2

How is this issue resolved?


This error occurs when DMA is disabled and the device is added.

It causes a divide-by-zero, which results in an error.

To work around this, the IP needs to be made local and  the below lines should be commented out of the .tcl file:

set maxi_clk_port [xget_hw_port_handle $mhsinst "M_AXI_ACLK"]
set maxi_clk_freq [xget_hw_subproperty_value $maxi_clk_port "CLK_FREQ_HZ"]
set mpath_delay [expr {(((1.0/$maxi_clk_freq) * 1e09)*2)-1}]

set mplb_clk_port [xget_hw_port_handle $mhsinst "MPLB_Clk"]
set mplb_clk_freq [xget_hw_subproperty_value $mplb_clk_port "CLK_FREQ_HZ"]
set mpath_delay [expr {(((1.0/$mplb_clk_freq) * 1e09)*2)-1}]

AR# 40302
Date Created 03/02/2011
Last Updated 07/07/2014
Status Active
Type General Article
  • EDK - 13
  • EDK - 13.1
  • AXI USB 2.0 Device Controller