Failed to read ROM table via AP 3 - Failed to start GDB server
UPDATE 04/30/24:
I no longer believe this is a debugger only problem. CM7 is always successful in flashing and debugging or running.
The ST Link GDB Server cannot flash the CM4 in either debug or Release mode. Please see attached file CM7_CM4_Release_Mode_Output.txt.
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UPDATE 04/29/24:
After spending 3 hours writing up all of these details below, I came back at the problem the next day with a fresh approach. I decided to see if I could get just CM7 running in both projects. Here is what I found.
CM7 is indeed being flashed properly from both projects. It is hanging in the debugger for both projects because the CM4 will not start (see CM4 DEBUGGER FAILS TO RUN below). It gets stuck in an infinite loop which makes perfect sense because CM4 is not running.
/* USER CODE BEGIN Boot_Mode_Sequence_1 */
while(__HAL_RCC_GET_FLAG(RCC_FLAG_D2CKRDY) != RESET) { asm("NOP"); }
/* USER CODE END Boot_Mode_Sequence_1 */
If I comment out the while loop it falls through to the next while loop which also waits for the CM4 but times out and jumps to the Error_Handler() which then enters its own while loop. This gave me the impression of a failed flash.
Only when I stop the debugger and reset the PH7 is it clear that the CM7 has been flashed properly because my led's start flashing a special sequence I programmed to let me know it is running.
To make this ridiculously long story short, my problem has been reduced to the CM4 not starting because of the:
'Failed to read rom table via AP 3' error
or the
'Failed to start GDB server, Error in initializing ST Link device' error.
Feel free to read everything below (I'm not deleting it because it took me 3 hours to put it together!) but the only relevant portion of it now is the CM4 DEBUGGER FAILS TO RUN which is what I need help with now.
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I've seen this issue in a few places. Some with solutions, none of which have worked for me. I am programming a Portenta H7 via a Portenta Breakout board with an ST Link v2 (please don't direct me to the Arduino forum. I have this conversation going over there as well).
CM4 DEBUGGER FAILS TO RUN
OR ST LINK IS FAILING TO CONNECT
In both projects, I start the CM7 debugger with no problems. When I start the CM4 debugger in either project, I get this error:
COM frequency = 4000 kHz
Target connection mode: Attach
Failed to read ROM table via AP 3
Error in initializing ST-LINK device.
Reason: Unknown. Please check power and cabling to target.
With this dialog popup:
Error in final launch sequence:
Failed to start GDB server
Failed to start GDB server
Error in initializing ST-LINK device.
Reason: (255) Unknown. Please check power and cabling to target.
Here is the CM7 and CM4 stack at this point:
STM32H747XI_CM7 Debug [STM32 C/C++ Application]
STM32H747XI_CM7.elf [cores: 0]
Thread #1 [main] 1 [core: 0] (Suspended : Signal : SIGTRAP:Trace/breakpoint trap)
0x800041c
<signal handler called>() at 0xfffffff9
0x804000
<signal handler called>() at 0xffffffff
arm-none-eabi-gdb (13.2.90.20230627)
ST-LINK (ST-LINK GDB server)
<terminated>STM32H747XI_CM4 Debug [STM32 C/C++ Application]
<terminated, exit value: 0>arm-none-eabi-gdb (13.2.90.20230627)
<terminated, exit value: 255>ST-LINK (ST-LINK GDB server)
ST Link connections are fine as I can download the Bootloader, CM7 and CM4 .elf files from STMCubeProgrammer.
- The Bootloader (portentah7_bootloader_mbed_hs_v2.bin)
- CM7 address 0x08040000
- CM4 address 0x08100000
- My linker file for both CM7 and CM4 FLASH entry are set accordingly
- Debugger configurations for both CM7 and CM4 Startup->Set program counter (hex): are set accordingly
The power mode for CM4, as suggested in this post, is generated correctly with my version of STM32CubeIDE (1.15.1)
HAL_PWREx_ClearPendingEvent();
HAL_PWREx_EnterSTOPMode(PWR_MAINREGULATOR_ON, PWR_STOPENTRY_WFE, PWR_D2_DOMAIN);
Also, these OB settings are checked:
NRST_STOP_D2
NRST_STBY_D2
This post on GitHub follows the same debugger setup as AN5361 Section 3 with one exception: in the CM7 configuration, it shows 'Halt all cores' as checked which contradicts AN5361 . Which one is correct or does it matter?
I also implemented this suggestion from that post:
while(__HAL_RCC_GET_FLAG(RCC_FLAG_D2CKRDY) != RESET) { asm("NOP"); }
Of course, all help/suggestions are greatly appreciated!
Here are my debugger settings for both cores:
CM7
CM4
