debugging "blinky" for MPU

So close yet so far...

Hardware: TI AM1707 EVM - ARM926EJ-S microprocessor (not MCU, so not officially supported in the device database)

Debugger: Segger J-Link

Application: GNU compiler toolchain + working LED code

When loaded with J-Link + GDB, the LEDs light up correctly

When loaded by J-Link + uVision, the debugger SEEMS to give me access to the board, but the application doesn't run correctly (starts near 0xFFFF0000, which is on-chip local ram)...

Am I missing something totally basic here? Any help would be greatly appreciated!!

-Jonathan

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  • A bit of progress, viewing the disassembly:

    When the debugger first loads, PC=0xFFFF0000.

    Next, force program counter to my application's entry address (0xC108010C)
    - opcodes here are random and incorrect, regardless of "Load Application at Startup"
    - if the Command "LOAD D:\led.elf" is issued, opcodes become all zero
    - "arm-none-eabi-objcopy -O ihex led.elf led.hex" + "LOAD D:\led.hex": nonzero opcodes, but still incorrect?

    So at least the problem is narrowed down to uVision not being able to load the application correctly into memory - probably an incorrect application output format? But not sure how to fix...

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  • A bit of progress, viewing the disassembly:

    When the debugger first loads, PC=0xFFFF0000.

    Next, force program counter to my application's entry address (0xC108010C)
    - opcodes here are random and incorrect, regardless of "Load Application at Startup"
    - if the Command "LOAD D:\led.elf" is issued, opcodes become all zero
    - "arm-none-eabi-objcopy -O ihex led.elf led.hex" + "LOAD D:\led.hex": nonzero opcodes, but still incorrect?

    So at least the problem is narrowed down to uVision not being able to load the application correctly into memory - probably an incorrect application output format? But not sure how to fix...

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