CortxA8: Error connecting to the target: (Error -1204 @ 0x3D5B) Unable to access the DAP.

Abedon Madril

I'm new to the CCS IDE application and am encountering a problem with JTAG connectivity resulting in the following error message:

CortxA8: Error connecting to the target: (Error -1204 @ 0x3D5B) Unable to access the DAP. Reset the device, and retry the operation. If error persists, confirm configuration, power-cycle the board, and/or try more reliable JTAG settings (e.g. lower TCLK). (Emulation package 5.1.641.0)

I am able to connect to my target from within u-boot and single step through the init phase of my TI SDK linux kernel. My suspicion is some hardware configuration is being changed/set by the kernel from within a privileged mode that is disabling the JTAG connection. I've searched through the forum and have found questions for the same or similar error message but haven't been able to fix my particular issue with the recommended solutions.

I'm currently using CCS version 6.1.0.00104 with the Spectrum Digital XDS560v2STM emulator.

Has anyone encountered this issue with CCS version 6.1.0 and the TI linux kernel?

Thanks in advance.

over 10 years ago

0 desouza over 10 years ago

TI__Guru**** 171609 points

Hi,

The thread below discusses the same issue.

Similarly to the original poster of the thread above, I was able to connect to my A8 after the Linux booted by applying the modification suggested and rebuilding the kernel.

You did not mention which device you are using, but if you are using the latest SDK for AM335x, the modifications must be done in a different file. I reproduce below what I did:

In the current kernel 3.14.26 the procedure is as follows:

- from inside the Linux kernel source code directory, open the file arch/arm/mach-omap2/omap_hwmod_33xx_data.c

- go to the definition of the structure am33xx_debugss_hwmod (line 162) and add the .flags option below:

static struct omap_hwmod am33xx_debugss_hwmod = {
       .name = "debugss",
       .class = &am33xx_debugss_hwmod_class,
       .clkdm_name = "l3_aon_clkdm",
       .flags = (HWMOD_INIT_NO_IDLE|HWMOD_INIT_NO_RESET),
       .main_clk = "trace_clk_div_ck",
       .prcm = {
               .omap4 = {
                       .clkctrl_offs = AM33XX_CM_WKUP_DEBUGSS_CLKCTRL_OFFSET,
                       .modulemode = MODULEMODE_SWCTRL,
               },
       },
       .opt_clks = debugss_opt_clks,
       .opt_clks_cnt = ARRAY_SIZE(debugss_opt_clks),
};

Hope this helps,

Rafael

0 Abedon Madril over 10 years ago

Prodigy 70 points

This did the trick. Thank you very much for your help.

AM

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CortxA8: Error connecting to the target: (Error -1204 @ 0x3D5B) Unable to access the DAP.