Duet 3 Flash custom firmware via swd

[A Former User]

Hi,

I was trying to create some custom firmware for the Duet 3 6HC board. The reason for this is, that the hardware supports all the necessary functionality but I don't need the WebServer etc. for my particular application. When I bought the Duet 3 I saw in the hardware docs, that there is a SWD connector. So I thought that I would be able to just open an openocd connection, compile my firmware, flash it on the chip via SWD and use a arm-none-eabi-gdb for debugging. Boy was I wrong

I am using the following:

• Duet 3 6HC v1.01
• STLink V2 and a STLink V2.1 turned into a Jlink, I have tried everything with both
• Openocd v0.11.0
• arm-none-eabi-gcc 10.2.1

Using the following command

openocd -f interface/jlink.cfg -c "transport select swd" -f target/atsamv.cfg

I am able to establish an openocd connection to the ATSAME70Q20B processor. I have build some dummy firmware using a Makefile Project created using ATMEL START for the corresponding processor. I was able to compile an elf file, connect my gdb to the openocd socket and flash that firmware. However as soon as I try to create a breakpoint in the main function to step through the programm, it gets stuck in the following backtrace loop and never reaches main:

#0  0x00800dbe in ?? ()
#1  0x20400100 in _sheap ()

I tried erasing over the jumper and reflashing the firmware. Didn't help. I then tried to restore the Reprapfirmware v3.3. I successfully build it using the tutorial, and tried to flash it over swd and got the following error:

(gdb) load
Loading section .text, size 0x8947c lma 0x400000
Loading section .ARM.extab, size 0x14f4 lma 0x48947c
Loading section .ARM.exidx, size 0x18f0 lma 0x48a970
Loading section .relocate, size 0x638 lma 0x48c260
Error finishing flash operation

openocd output:

Info : erasing lock regions 0-35...
Info : erasing lock region 0
Info : erasing lock region 1
Info : erasing lock region 2
Info : erasing lock region 3
Info : erasing lock region 4
Info : erasing lock region 5
Info : erasing lock region 6
Info : erasing lock region 7
Info : erasing lock region 8
Info : erasing lock region 9
Info : erasing lock region 10
Info : erasing lock region 11
Info : erasing lock region 12
Info : erasing lock region 13
Info : erasing lock region 14
Info : erasing lock region 15
Info : erasing lock region 16
Info : erasing lock region 17
Info : erasing lock region 18
Info : erasing lock region 19
Info : erasing lock region 20
Info : erasing lock region 21
Info : erasing lock region 22
Info : erasing lock region 23
Info : erasing lock region 24
Info : erasing lock region 25
Info : erasing lock region 26
Info : erasing lock region 27
Info : erasing lock region 28
Info : erasing lock region 29
Info : erasing lock region 30
Info : erasing lock region 31
Info : erasing lock region 32
Info : erasing lock region 33
Info : erasing lock region 34
Info : erasing lock region 35
Warn : keep_alive() was not invoked in the 1000 ms timelimit. GDB alive packet not sent! (2156 ms). Workaround: increase "set remotetimeout" in GDB
Info : SWD DPIDR 0x0bd11477
Error: Failed to write memory and, additionally, failed to find out where
Error: failed to buffer page at 0x00400000
Error: error writing to flash at address 0x00400000 at offset 0x00000000
Info : SWD DPIDR 0x0bd11477
Polling target samv.cpu failed, trying to reexamine
Info : SWD DPIDR 0x0bd11477
Info : SWD DPIDR 0x0bd11477
Error: Could not find MEM-AP to control the core
Examination failed, GDB will be halted. Polling again in 100ms
Info : SWD DPIDR 0x0bd11477
Info : SWD DPIDR 0x0bd11477
Error: Could not find MEM-AP to control the core
Info : SWD DPIDR 0x0bd11477
Info : SWD DPIDR 0x0bd11477
Info : SWD DPIDR 0x0bd11477
Info : SWD DPIDR 0x0bd11477
Info : AP write error, reset will not halt
Error: DP initialisation failed
Error executing event gdb-flash-write-end on target samv.cpu:

What am I missing? Can someone provide me with a tutorial on how to flash the Duet 3 Mainboard via SWD?

Any help is greatly appreciated. Best regards

[alankilian]

@andgl

I really don't know much how to help, but do these files in THIS GUTHUB LOCATION help?

They talk about openocd and SWD.

or maybe the linker script in THIS LOCATION?

[A Former User]

@alankilian Thank you for your response. Sadly the openocd script in github is for another in-cirtcuit debugger device, namely a cmsis-dap. I am using a stlink however and my openocd command basically contains the whole contents of the script, but as cmd line parameters. As far as I can tell there should not be an issue using the stlink over the cmsis-dap (at least in theory)

[dc42]

@andgl I have no problem flashing firmware or debugging over SWD using a Atmel ICE. I originally tried using a Black Magic SWD probe instead, but it turned out that the firmware didn't support the Atmel/Microchip ATSAM MCUs.

[A Former User]

@dc42 If it's not too much to ask, could you please try flashing a custom Atmel Start project with your setup? Just to make sure, that the issue is not due to some wrong linkerfile settings. Atmel Start can generate you a makefile project with a dummy main function for the ATSAME70Q20B without having to register or anything.

[dc42]

@andgl if you are using Atmel Start then be aware that it is very buggy, based on my experience with using Atmel Start with the SAME5x processors. Microchip doesn't support it and hasn't fixed showstopper bugs that I reported more than three years ago. I don't have time to set up a SAME70 Atmel Start project and work through the likely bugs.

Are you sure that your stlink hardware and openocd firmware will work with the SAME70? Have you tried loading and debugging the same Atmel Start project using a Atmel ICE?