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Altera_Forum
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15 years ago

Multiple processors fail to communicate with peripherals

I have a working single-processor build on a cyclone III, running at 100 MHz that includes a jtag-uart, and RS-232 UART, some debug output PIO pins, etc. Everything in the SOPC system is running at 100 MHz. I am wanting to divide my project into two NIOS processors. I added a 2nd NIOS along with a timer, some dual-port on-chip memory, and a mutex, similar to the multiprocessor design tutorial. Both processors run from SDRAM (different offset addresses). I am trying to get this up and running, using slightly modified hello_world_multi.c file to test it. However, when I try to run the multi-processor build, I don't see any prints on the NIOS II terminal. I tried using the RS-232 UART for the print statements and also tried toggling the debug pins, and none of it seems to work. I can step through the code in debug mode just fine, and it seems to work as expected, except that when it executes the printf() command, nothing happens.

I have tried variations of the SOPC system, adding and removing pipeline bridges. The result is usually the same, although sometimes one of the processors will fail verify or will simply be left paused.

I am wondering if putting in the second processor and related peripherals has somehow screwed up the timing in the SOPC system? I wonder if I need to change the phase shift on the PLL for the SDRAM clock? That doesn't seem to make sense since (at least on a couple of my builds) I seem to be able to operate from the SDRAM just fine, but cannot seem to communicate to the other peripherals. Is the fact that my peripherals are behind a pipeline bridge an issue? I would think that would help the performance.

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    It turns out I had the incorrect "--instance" settings when selecting Run in the NIOS IDE. After selecting "Load JDI file" the NIOS2-download argument says "--instance=1", but in the target connection tab the NIOS2-terminal argument says "--instance=0". I knew these settings were important, and I thought they had to be the same, so I tried to make them match. This was wrong. I needed to just let them stay at their default settings, and it all worked out. I just need to make sure the "--instance" on the Main tab is correct for each processor.

  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    If you want use NIOS IDE terminal you need to configure it to connect to particular RS232 port. Choose RUN->RUN->Target Connection there is NIOS II Terminal Communication device.

    If you use multiple processor you cannot use JTAG-UART. Thus you should use physical ports and need to connect it to computer and using above description connect NIOS II terminal. Moreover this is not enough, go to your software project select it and with right click of the mouse choose System Library Properties. There is three points: Stdout, Stdin, Stderr and choose UART in windows near these description. It points printf() to your UART.

    If I understood your problem correctly it should help.