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Tool/software: Code Composer Studio
I’ve got a custom board that uses the TM4C129ENCZAD. Ultimately I’d like to use this for a TI-RTOS project, but I’m seeing strange behavior when programming it. Here are the steps I’ve tried to isolate the problem:
First, I created a new project from the hello world basic example template in CCS, which builds and runs just fine. Then I created a new empty RTSC project, got it configured and built, but when I try to debug I get this error:
CORTEX_M4_0: GEL Output:
Memory Map Initialization Complete
CORTEX_M4_0: JTAG Communication Error: (Error -1170 @ 0x0) 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 6.0.222.0)
CORTEX_M4_0: Failed to remove the debug state from the target before disconnecting. There may still be breakpoint op-codes embedded in program memory. It is recommended that you reset the emulator before you connect and reload your program before you continue debugging
From then on, each time I try to program it I get error -1170. I can't even go back to the hello world project unless I perform the dbgjtag device unlock procedure. I’ve tried lowering TCLK, but that doesn’t fix it. In fact, the target configurations are identical for both projects.
I'm using CCS version 6.1.3.00034 and an XDS200 debug probe. What's different about an RTSC project that could cause the debugger to fail like this?
As a sanity check, I created another set of hello world and RTSC projects for an EK-TM4C129EXL demo board that I have, and both of these work--it's just the ENCZAD RTSC that's giving me problems. Where should I look next?
Did the working bare metal example call SysCtlClockFreqSet?I suppose the hardware on my custom ENCZAD board could be another variable, but a bare metal project works there, so I'm guessing the hardware is ok.
The SYS/BIOS start-up code for a TM4C129 device will set the clock configuration according to the parameters on the SYS/BIOS Clocking Options:
If the SYS/BIOS clocking options result in an invalid clock source, e.g. attempts to use an external crystal but the external crystal is missing / faulty, then it can lead to the observed symptoms of the debugger being locked out until the device is unlocked.
