Hi,
When I am trying to detect my target platform for i.MX8Mplus processor using the ARM Development Studio v2025.0-1 . I am getting prints like this
[23/09/25 12:02:59] Arm Development Studio v2025.0-1, build number 2025010903
[23/09/25 12:02:59] JTAG Clock Speed : 7500000Hz
[23/09/25 12:02:59] Beginning Autodetection
[23/09/25 12:03:00] --- --- ---
[23/09/25 12:03:00] Connected to Debug Probe
[23/09/25 12:03:00] Counting devices:
[23/09/25 12:03:00] DR Chain [136]:
00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
00000000
[23/09/25 12:03:00] Device Count: 136
[23/09/25 12:03:00] Detected number of devices = 136, maximum allowed = 128. This problem is usually a result of the scanchain not acting correctly when using JTAG scans to count the number of devices.
[23/09/25 12:03:00] Performing legacy SWD->JTAG switch
[23/09/25 12:03:00] Performing Dormant Mode SWD->JTAG switch
[23/09/25 12:03:00] Disconnected from Debug Probe
[23/09/25 12:03:05] JTAG detection failed, trying SWD
[23/09/25 12:03:05] WARNING - Multi-drop SWD is not supported, a single DAP on the scanchain has been assumed.
[23/09/25 12:03:05] The scanchain must be built manually if more scanchain devices are present.
[23/09/25 12:03:07] --- --- ---
[23/09/25 12:03:07] Disconnected from Debug Probe
[23/09/25 12:03:07] Unable to connect to device ARMCS-DP
Hi again
I'm not very familiar with the i.MX8Mplus, but the board documentation "Getting Started with MCUXpresso SDK for EVK-MIMX8MP.pdf" says:
>For the security reason, only after the U-Boot is boot up, the JTAG can be allowed to connect to M core.
Is your board booting into Linux? If not, I think you'll need to (at least start the) boot into Linux:1) Prepare a microSD card with a Linux image2) Connect a serial terminal emulator such as PuTTY to the COM port (as shown in the guide above)3) Power up the board and hit a key on the U-Boot startAlso, check pin JTAG_MOD. Some users on the NXP Community have reported related issues there. See e.g.
https://community.nxp.com/t5/i-MX-Processors/I-MX8M-Plus-Enter-JTAG-Debug/m-p/1577793
and
https://community.nxp.com/t5/i-MX-Processors/iMX8M-Plus-Cortex-M7-JTAG-Debug-quot-Could-not-measure-IR-len/td-p/1660528
Hope this helps
Stephen
Hi Stephen,
We connected the USB-UART port in I.MX8MPLUS to PC(Windows) and connected to putty. In U-Boot we stopped the booting then we did debug in arm development studio using DStream-ST jtag. Still we are getting the same error.
Hi againSorry, I meant to add:After interrupting u-boot, issue this command:u-boot=> bootaux 0x7e0000## Starting auxiliary core stack = 0xEDFE0DD0, pc = 0x28040000...In our tests (with an early board/distro) we also needed to issue this command, but sorry, I don't know whether it will be needed for your setup, or whether the values might need to be different:u-boot=> md.w 0x30340058 0xFFFFFFFEFor more information see section 4.7.4.1.2 ofwww.nxp.com/.../UG10163.pdfIf you still need more help, I suggest you reach out to the NXP Community athttps://community.nxp.com/who are best placed to advise on the specifics of their board boot, or "Open a Support Case" with Arm using the Support link at the bottom of this page.Stephen