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Observer sseppala
Observer
2,928 Views
Registered: ‎02-28-2013

Microblaze GDB PC always stalls at 0x14

I can build the system and make a simple test application, however when I connect via XMD and program the bitstream, then connect with  mb-gdb and load the file, no matter what I do, even a simple stepi, results in the GDB freezing,and the following coming over the XMD interface.

XMD% Error: MicroBlaze Pipeline Stalled on a Blocking Instruction or Invalid Bus
 Access
        Stalled PC: 0x00000014
        Try Resetting the Processor to Continue..Processor is stalled at address
 0x4. UNABLE to STOP MicroBlaze

 

I have tried programming it, ensureing that the I & D BRAMS are on the same memory address,  downloading the file via XMD, downloading and loading the file via XMD, and just using the GDB load operation. but every time it stalls at 0x14.  and I can never get out of _start() at 0x0000000000

Can anyone shed some light on this issue?

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5 Replies
Observer sseppala
Observer
2,874 Views
Registered: ‎02-28-2013

Re: Microblaze GDB PC always stalls at 0x14

I've now tried to read and write to the `microblaze_bram_I` , `microblaze_bram_d` as well as their AXI counterparts to ensure that I can write to the memory. It appears there is some kind of application running as the values change periodically, however when I write to them, only some of the buts change, and keep flopping back and forth to different values.

 

I program the device with the system_bmm.bit file in the applications Debug/ directory, and the system.bmm file that is in the hardware description directory.  I have tried without the system.bmm file and there is no change whatsoever.

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Observer sseppala
Observer
2,869 Views
Registered: ‎02-28-2013

Re: Microblaze GDB PC always stalls at 0x14

After attempting to write to the `MCB_DDR3` `axi_s6_ddrx` module and running a simple hello_worl program, I have found that this data stays zero no matter what. I have programed the FPGA before and after to ensure that it isn't a mistake.

I wrote to it after connecting XMD to the device. 

mcb_ddr3_S0_AXI_BASEADDR = 0x80000000 -- size = 0x80000000

 

Connected to "mb" target. id = 0
Starting GDB server for "mb" target (id = 0) at TCP port no 1234
XMD% mwr 0x81000000 0xbeefdead
XMD% mrd 0x81000000
81000000:   00000000

XMD% mrd 0x81000000
81000000:   00000000

XMD% mrd 0x80000000
80000000:   00000000

XMD% mrd 0x80001000
80001000:   00000000

XMD% mwr 0x80001000 0xdeaddead
XMD% mrd 0x80001000
80001000:   00000000
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Moderator
Moderator
2,862 Views
Registered: ‎09-12-2007

Re: Microblaze GDB PC always stalls at 0x14

Can you try use bram (lmb bram) for the boot vectors. Or, hold the microblaze in reset until the DDR is up.

The microblaze is stalling as it is executing invalid instruction (0x00000000).

Also, looks like you have issued with your ddr
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Observer sseppala
Observer
2,857 Views
Registered: ‎02-28-2013

Re: Microblaze GDB PC always stalls at 0x14


@stephenm wrote:
Can you try use bram (lmb bram) for the boot vectors. Or, hold the microblaze in reset until the DDR is up.

The microblaze is stalling as it is executing invalid instruction (0x00000000).

Also, looks like you have issued with your ddr


How do I go about that?  Currently upon reset the microblaze sits at 0x00000000 . My understanding was that it starts there an then loads the address of the main function and jumps to it. Is that incorrect?
The microblaze is held in reset. It sits at reset until after I load the symbol table in GDB.

Yes, it would seem so. However I have used this board before and there were no issues with it, so there is something wrong with the system and not the board.  It is a SP605 Dev Board.

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Observer sseppala
Observer
2,856 Views
Registered: ‎02-28-2013

Re: Microblaze GDB PC always stalls at 0x14

I misread your post. IMB BRAM is what I am trying to load my program to be executed into. I am still not sure how I would setupthe boot vectors to there if the micro blaze boots with 0x000000000
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