NIOS II Control Unit (CU)

[Altera_Forum]

hi, 

I want know who can I send an instruction from NIOS II to another NIOS II processor. when I want execute an instruction I send it to the other processor. can nios II do this??   thank for all members

[Altera_Forum]

What do you exactly mean with an "instruction"? A processor instruction? 

 If I've understood what you intend, I will produce a system where nios_a sends data to a peripheral (can be a simple PIO), which is then read by nios_b (can be also be a PIO, possibly using a IRQ) and then nios_b decodes the parallel data read from nios_a and executes that instruction (or intended C function).

[Altera_Forum]

thank you for reply, 

 I want make a design with NIOS II like SIMD architecture when a master processor can send instruction to others processors. instruction can be a function written in C language. the main problem is how can I access internal registres of NIOS II like IR (Instruction Reg) to read current instruction.  thank again for all members

[Altera_Forum]

I don't see why you need to read IR registers at all, sorry. What I'm saying is that your master processor will send the intended instruction to all the slaves through a simple PIO interface (IOWR). Then, each slave will read (IORD), decode and execute that instruction. If needed, also the slaves can return data or a "done" signal to the master. If this is not what you intend to do, maybe you can explain in more detail the requirements of your system.

[Altera_Forum]

I would think that you would want to build a master module for the delegating CPU with some single line signaling to Slave modules attached to each slave CPU which can then in turn send simple signals like "idle" "finished_last_operation" "working" back to the main CPU to prevent latency and need to create an extra processing layer in whatever protocol you develop to send instructions. Just some general architecture observations. All that could be hooked up Point To Point through the switch fabric. Good luck, sounds like an interesting project. I wish I could do something like that for a while rather than building glue logic.

[Altera_Forum]

thank jrierab & alt1000 for reply, 

I want discuss the solution given by jrierab. If I try to implement this idea, how can I send the instruction out of the Master processor. you mean that I implement a protocol with C language that decodes the instruction. the Nios will use their PIOs interface to send instruction. can you explain to me how can I do this with NIOS.  have a nice day

[Altera_Forum]

I mean the following. Your NIOS master puts a coded instruction (or one already decoded, "one-hot" bit instruction code) in the PIO output port. This is a simple IOWR write in C code. The slave processors have each one a PIO input port (which is externally, HDL, connected to the master's PIO port). So, as soon as the master puts the instruction out, all the slaves see it. You can even implement an interrupt routine in the slaves processors, if you want. In any case, the input PIO can be read with a simple IORD in C. Then, the instruction will be decoded (if needed) in each slave and executed separately in each processor. 

 Another way could be to implement a custom instruction in the master, which connects directy to the input PIO in the slaves processors. The process is more or less the same.

[Altera_Forum]

why nobody answer in my topics?

[Altera_Forum]

baghiero83, has your comment anything to do with this topic? 

 Indeed, I see already some answers in "your topics" http://www.alteraforum.com/forum/showthread.php?t=5915.   You have registered only today... What did you expect? This is not a chat room.

[Altera_Forum]

Hello, 

 If I understand The NIOS send the 32-bits instruction (as programmed in the NIOS assembly) via its PIO and it can be read by the slave? But how can the slave decode this instruction?? Can you please give an example on one instruction?  Thank you for your cooperation. Best regards,