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12436 Discussions

Nios II TSE design requires being loaded twice???

Honored Contributor II

I am using a DE2-115 Cyclone IV board. For some reason, I need to upload my compiled C code a second time in order for it to work and pass network traffic. 


I am using a Triple Speed Ethernet design. Anyone know what might cause a design to not work the first time but work the second time it is uploaded to the FPGA? Is there a common mistake that might be the cause of it only working on a second upload to the board?
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2 Replies
Honored Contributor II

Perhaps your code is not waiting long enough at boot for 'something'. However, after re-loading, you have given the hardware/software long enough for something to happen such that the code then functions as expected. 



Honored Contributor II



I had finally figured it out after a month of troubleshooting. I thought it was timing constrains (*.sdc file) but had the same problem after correcting 200+ violations. 


What was happening was I was configuring the PHY chips BEFORE setting their proper addresses (0x10 and 0x11 for the Terasic DE2-115 Cyclone IV board). In essence, the first load was configuring PHY chips that didn't exist, then stored the correct addresses for them (0x10 and 0x11). The second load completed PHY configuration.