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EPCS problem

Altera_Forum
Honored Contributor II
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Hello all: 

 

First I will describe the system we are using: 

 

- Custom board 

- NIOS II 5.1 and Quartus II 5.1 SP1 

- EPCS as unique non volatile memory. We intend to use it to store both FPGA configuration file and NIOSII application at power up. 

- Reset address pointing at 0x00000000 which is the EPCS base address. 

 

So the problem is that when there is a .sof file stored in the EPCS, the FPGA is always reconfiguring. Herewith an example is shown to let you understand the problem: 

 

- If we have the EPCS empty, we can use the Quartus Programmer to download a .sof file without problems. And then we can download a NIOS application. 

- If there is a sof file programmed in the EPCS, once the FPGA is configured, it is configured again and again. (we can see with the oscilloscope clk and data signals with activity). So if in this situation we use the Quartus programmer to download another sof, it is well downloaded but then the FPGA will continue reconfiguring from the EPCS deleting the design download with the Quartus and progamming it with the one stored in EPCS. 

 

So we think it is due to the fact that we have the reset address pointing to the EPCS wich is our unique non volatile memory, so when the FPGA confiures, the NIOS tries to search the application in the EPCS, but he finds a sof file so a new configuration process is performed.  

 

The question is how can we have in the same EPCS the sof and an application without having this problem? I think that many people use the EPCS for this purpouses, so please letus know what we are doing wrong. 

 

Thanks in advance, 

Luis
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Altera_Forum
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