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Does User clock frequency in QSYS for HPS-to-FPGA clock work?

Altera_Forum
Honored Contributor I
1,009 Views

We have a project using Quartus 13.1 and are trying to configure the HPS-to-FPGA user0 clock to be 50 MHz (instead of 100). The dialog seems to take 50 MHz fine, but when we generate the handoff files for the FPGA, there doesn't seem to be a difference between the generated files. Specifically, we get the following in the pll_config.h file: 

 

#define CONFIG_HPS_MAINPLLGRP_VCO_DENOM (0)# define CONFIG_HPS_MAINPLLGRP_VCO_NUMER (63)# define CONFIG_HPS_MAINPLLGRP_MPUCLK_CNT (0)# define CONFIG_HPS_MAINPLLGRP_MAINCLK_CNT (0)# define CONFIG_HPS_MAINPLLGRP_DBGATCLK_CNT (0)# define CONFIG_HPS_MAINPLLGRP_MAINQSPICLK_CNT (3)# define CONFIG_HPS_MAINPLLGRP_MAINNANDSDMMCCLK_CNT (3)# define CONFIG_HPS_MAINPLLGRP_CFGS2FUSER0CLK_CNT (15)# define CONFIG_HPS_MAINPLLGRP_MAINDIV_L3MPCLK (1)# define CONFIG_HPS_MAINPLLGRP_MAINDIV_L3SPCLK (1)# define CONFIG_HPS_MAINPLLGRP_MAINDIV_L4MPCLK (1)# define CONFIG_HPS_MAINPLLGRP_MAINDIV_L4SPCLK (1)# define CONFIG_HPS_MAINPLLGRP_DBGDIV_DBGATCLK (0)# define CONFIG_HPS_MAINPLLGRP_DBGDIV_DBGCLK (1)# define CONFIG_HPS_MAINPLLGRP_TRACEDIV_TRACECLK (0)  

 

This seems to set up the HPS-to-FPGA user0 clock to be 100 MHz (25 MHz * (63+1) / (15+1) = 100). Shouldn't the CONFIG_HPS_MAINPLLGRP_CFGS2FUSER0CLK_CNT variable be set to 16 here? 

 

-Mike
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2 Replies
Altera_Forum
Honored Contributor I
115 Views

Hi, 

 

I don't know why Qsys didn't generate it as configured, but you can edit the pll_config.h manually and set the proper settings for your application. 

But be patiant, all the frequencies you configure have to fit to the operating range of the device (have a look in the datasheet). 

 

More about clock customization can be found here: 

http://www.rocketboards.org/foswiki/documentation/preloaderclockingcustomization
Altera_Forum
Honored Contributor I
115 Views

Hi, 

 

I was trying to find out the value of f2h_axi_clocl, h2f_lw_axi_clock but couldn't locate the value in qsys. Can anyone please let me know or correct me if anything wrong i am doing. 

 

Thanks, 

Pankaj
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