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JTAG chain DSP and PLD

Mauro Fantina
Genius 3800 points
Other Parts Discussed in Thread: TMS320F28069

Hello, I'm using one TMS320F28069 dsp texas and 2 EPM1270T144 pld altera.

Can I connect this three devices in JTAG chain (TDO of one device towards TDI of the nex device)

ad use XDS100V2 debugger and CCSv5 without problems ?

Have I to specify in the CCSv5 the bypass ?

Thankyou in advice

  • 0
    Prodigy 70 points

    I hope it's still relevant.

    Anyway, i am now debugging a board with JTAG chain with 28069 first and a Lattice PLD second, and it does not work. I cannot connect neither to the MCU nor to the PLD, only if i break the chain.

    So be careful.

  • 0 in reply to Gregory Kornblum1
    Prodigy 70 points

    Ok, actually it seems to work somehow. It's just the CCS 5, that is so not intuitive. You have to bypass the other device, but you can never guess where is this option hidden.

    Go to File->New->Target Configuration File->Advanced Setup - Target Configuration, then add a bypass device.

    On other hand, it seems that the TMS320F28069 TDO is stuck on '1' when i am trying to communicate with the PLD, so it's still not working...

    Good Luck!

  • 0 in reply to Gregory Kornblum1
    Prodigy 70 points

    Ok, so the PLD works now too.

    Another thing that is hard to find: 28069 instruction register length is 38 bit. This is used to bypass it when programming the Lattice.

    Also the MCU's TRST signal should be tied to VCC, otherwise the JTAG chain is broken. Personally i made this connection on the JTAG POD connector, so i don' t need to patch the board.

    Good luck!

  • 0 in reply to Gregory Kornblum1
    Prodigy 50 points

    In my opinion the easiest way to find the instruction register (IR) length is to download the BSDL device model for your device provided by TI.

    In your example you can find it here: TMS320F28069 technicaldocuments in the chapter "models". Open this file and search for the attribute "INSTRUCTION_LENGTH of".

    Lattice also makes it easy for you: In the ispVM tool, when you select the bypass device, you can enter the IR length by hand or you can simply import the BSDL model file.