CPU TAP NOT FOUND

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    • CPU TAP NOT FOUND

      I am not able to connect to my target. Let, me know what to do-

      ./JLinkExe
      SEGGER J-Link Commander V7.20 (Compiled Apr 28 2021 17:38:41)
      DLL version V7.20, compiled Apr 28 2021 17:38:26


      Connecting to J-Link via USB...O.K.
      Firmware: J-Link V10 compiled Apr 27 2021 16:35:48
      Hardware version: V10.10
      S/N: 50117015
      License(s): GDB
      VTref=3.354V



      Type "connect" to establish a target connection, '?' for help
      J-Link>connect
      Please specify device / core. <Default>: RISC-V
      Type '?' for selection dialog
      Device>RISC-V
      Please specify target interface:
      J) JTAG (Default)
      S) SWD
      T) cJTAG
      TIF>JTAG
      Device position in JTAG chain (IRPre,DRPre) <Default>: -1,-1 => Auto-detect
      JTAGConf>
      Specify target interface speed [kHz]. <Default>: 4000 kHz
      Speed>
      Device "RISC-V" selected.



      Connecting to target via JTAG
      ConfigTargetSettings() start
      ConfigTargetSettings() end
      TotalIRLen = 20, IRPrint = 0x008421
      JTAG chain detection found 4 devices:
      #0 Id: 0xDAB17001, IRLen: 05, Unknown device
      #1 Id: 0xDBB17001, IRLen: 05, Unknown device
      #2 Id: 0xDCB17001, IRLen: 05, Unknown device
      #3 Id: 0xDDB17001, IRLen: 05, Unknown device
      ConfigTargetSettings() start
      ConfigTargetSettings() end
      TotalIRLen = 20, IRPrint = 0x008421
      JTAG chain detection found 4 devices:
      #0 Id: 0xDAB17001, IRLen: 05, Unknown device
      #1 Id: 0xDBB17001, IRLen: 05, Unknown device
      #2 Id: 0xDCB17001, IRLen: 05, Unknown device
      #3 Id: 0xDDB17001, IRLen: 05, Unknown device


      ****** Error: CPU-TAP not found in JTAG chain
    • Hi,
      Thank you for your inquiry.

      Some additional information would be useful:
      1) What is the exact name of the device you are trying to connect to?
      2) Are you working on an evaluation board or custom hardware.
      If evaluation board, which one?

      Best regards,
      Fabian
      Please read the forum rules before posting: Forum Rules

      Keep in mind, this is not a support forum. Its main purpose is user to user interaction.
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      Should you be entitled to support you can contact us via our support system: segger.com/ticket/


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    • Hello,

      Unfortunately, for RISC-V (unlike for ARM) there are no standardized JTAG IDCODEs for the JTAG TAPs that would allow identification as a RISC-V DM TAP.
      Just because the IRLen is 5 for RISC-V TAPs, it does not mean that any TAP with IRLen 5 is a RISC-V TAP (there are some counter examples I could tell).

      Do you have 4 RISC-V cores on your target?
      Did you assign the TAP Ids? I am just confused because there are 4 TAPs on your device and all of them have different TAP Ids. (I would have expected the same TAP Id 4 times)

      For Syntacore RISC-V TAPs, the J-Link software expects
      DEBx_xxx1
      as TAP Id. So you you assigned them in your case, by making sure to match the pattern above, J-Link will detect the RISC-V TAPs properly.


      BR
      Alex