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Memory or registers and JTAG

Hi, I read a lot of stuffs on JTAG and SVF file, but I still can't figure out how to read back multiple memory spaces or multiple registers via JTAG. I used BSCAN_SPARTAN3 and USER1 Register, but that only allows you to read back one register. I need to read back at least 10 registers or memory spaces via JTAG. Is it possible to do this at all? Thanks, AL

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AL
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figure out how to read back multiple memory spaces or multiple registers via JTAG. I used BSCAN_SPARTAN3 and USER1 Register, but that only allows you to read back one register. I need to read back at least

10 registers or memory spaces via JTAG. Is it possible to do this at all? Thanks, AL

They don't call them 'chains' for no reason. Your 'register' is really the chain of all the registers you want to shift in/out, or you can connect a register mux to one user chain and control the mux select signal using the other. You will have to serialize in and out your registers from the SVF bitstream or add the selection commands to the SVF process (depends on the capabilities of your SVF tool).

Cheers.

-- PabloBleyerKocik /"Mama said to get things done pbleyer / you better not mess with major Tom" @embedded.cl / -- Ashes to ashes, David Bowie

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Pablo Bleyer Kocik

Hi, Thanks for the response, but I now have problem with using the SVF file. I used the svf2xsvf and play xsvf utilities provided by APP058. Does anyone know a valid way for using these utilities? If I have my device programmed in IMPACT and then used this utility, I can see TCLK, TMS, and TDI, I don't see TDO for some reason. If I used this utility without having my FPGA programed in IMPACT. I don't see any TAP pins at all. Has anyone successfully used these tools???? Thanks, Ann

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AL

SVF file. I used the svf2xsvf and play xsvf utilities provided by APP058. Does anyone know a valid way for using these utilities?

Also check out XAPP503.

I can see TCLK, TMS, and TDI, I don't see TDO for some reason. If I used this utility without having my FPGA programed in IMPACT. I don't see any TAP pins at all. Has anyone successfully used these tools???? Thanks, Ann

IIRC, these tools are meant to configure and/or program devices with an application like iMPACT. It seems to me that you are trying to use iMPACT as a generic tool to introduce/extract information from your device using JTAG. I don't know if this is actually possible. I know that you can check the TDO values returned with a value and mask, but I don't remember seeing commands that dump arbitrary TDO values in a comfortable format for post-processing. You will need a better tool to do that.

I use my own Java tools to read and write the BSC registers of my designs through parallel or USB interfaces. They are not plug-n-play but if you are interested I can make part of them available for download.

Cheers.

-- /"Malgr=E9 les murs qui ensevelissent PabloBleyerKocik / LA CROIX DU SUD pbleyer / Est le seul avion qui subsiste" @embedded.cl / -- A=E9roplane, Vicente Huidobro

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Pablo Bleyer Kocik

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