Debug STM32F103 with openocd

Debug STM32F103 with openocd

background

When AWTK runs on STM32, the Keil management project is used by default. Generally, when buying a development board, the manufacturer provides the keil project, which is more convenient to transplant and easy to use, but the follow-up maintenance is more troublesome:

• AWTK often adds new files (such as new controls), it is very troublesome to synchronize to keil, each project needs to be modified, and the documents also need to be updated synchronously.

• AWTK's comments are in Chinese. In order to ensure that each compiler can compile normally, AWTK source files generally use UTF-8 With BOM encoding. If you use Keil to modify the code, it will remove the BOM after saving, and then you have to use other tools to add the BOM back.

Also, I personally don't really like working under Windows. Always hope to use gcc to compile, use gdb to debug. Tried it before, without success. Recently, I looked at rust-embedded and found that openocd can be used to debug, and it can be used for personal testing.

I have a stm32f103ze board in hand, which is a little different from the example provided by rust-embedded and needs to be improved. Make a note here for later use when transforming the AWTK compilation script.

1. Install related packages

The installation method under Mac is as follows:

# Rust
brew install rust

# GDB
brew install armmbed/formulae/arm-none-eabi-gcc

# OpenOCD
brew install openocd

# QEMU
brew install qemu

After installation, you need to add cargo's bin directory to the environment variable PATH.

export PATH="$HOME/.cargo/bin:$PATH""

This step is very important, otherwise rustup cannot be found, or the following error occurs when compiling:

error[E0463]: can't find crate for `core`
  |
  = note: the `thumbv7m-none-eabi` target may not be installed

Install cargo-generate

cargo install cargo-generate

2. Generate a rust project

Run the following command, enter app for the project name

cargo generate --git https://github.com/rust-embedded/cortex-m-quickstart

enter the app

cd app

3. Modify the configuration

Set the target, STM32F103 uses thumbv7m-none-eabi

rustup target add thumbv7m-none-eabi

You can also modify .cargo/config directly.

4. Modify memory.x

MEMORY
{
  /* NOTE 1 K = 1 KiBi = 1024 bytes */
  /* TODO Adjust these memory regions to match your device memory layout */
  /* These values correspond to the LM3S6965, one of the few devices QEMU can emulate */
  FLASH : ORIGIN = 0x00000000, LENGTH = 256K
  RAM : ORIGIN = 0x20000000, LENGTH = 64K
}

The address of the flash of stm32f103ze is 0x8000000, the size is 512K, and it is changed to the following:

MEMORY
{
  /* NOTE 1 K = 1 KiBi = 1024 bytes */
  /* TODO Adjust these memory regions to match your device memory layout */
  /* These values correspond to the LM3S6965, one of the few devices QEMU can emulate */
  FLASH : ORIGIN = 0x8000000, LENGTH = 512K
  RAM : ORIGIN = 0x20000000, LENGTH = 64K
}

5. Compile

cargo build

In the document, several commands are provided to view the generated executable file, but it seems that they cannot be used:

cargo readobj --bin app -- -file-headers

Prompt error:

Finished dev [unoptimized + debuginfo] target(s) in 0.02s
Failed to execute tool: readobj

You can use the arm-none-eabi-xxx command directly instead:

arm-none-eabi-readelf -h target/thumbv7m-none-eabi/debug/app

We can look at the location and size of the code (mainly to confirm whether it is consistent with memory.x)

arm-none-eabi-size -A -x target/thumbv7m-none-eabi/debug/app

output:

target/thumbv7m-none-eabi/debug/app  :
section              size         addr
.vector_table       0x400    0x8000000
.text               0x558    0x8000400
.rodata             0x138    0x8000958
.data                 0x0   0x20000000
.bss                  0x0   0x20000000
.uninit               0x0   0x20000000
.debug_abbrev      0x1432          0x0
.debug_info       0x21e99          0x0
.debug_aranges     0x1ca0          0x0
.debug_ranges     0x17f30          0x0
.debug_str        0x2b41f          0x0
.debug_pubnames    0x9800          0x0
.debug_pubtypes     0xad8          0x0
.ARM.attributes      0x32          0x0
.debug_frame       0x5b5c          0x0
.debug_line       0x2643b          0x0
.debug_loc          0x17e          0x0
.comment             0x6d          0x0
Total             0x9f1d6

6. Debug

Modify openocd.cfg

The original content is as follows:

# Sample OpenOCD configuration for the STM32F3DISCOVERY development board

# Depending on the hardware revision you got you'll have to pick ONE of these
# interfaces. At any time only one interface should be commented out.

# Revision C (newer revision)
source [find interface/stlink-v2-1.cfg]

# Revision A and B (older revisions)
# source [find interface/stlink-v2.cfg]

source [find target/stm32f3x.cfg]

Because I am using jlink, I changed it to the following:

# Sample OpenOCD configuration for the STM32F3DISCOVERY development board

# Depending on the hardware revision you got you'll have to pick ONE of these
# interfaces. At any time only one interface should be commented out.

# Revision C (newer revision)
source [find interface/jlink.cfg]

source [find target/stm32f3x.cfg]

start openocd

The normal output is as follows, prompting to listen to port 3333:

Open On-Chip Debugger 0.11.0
Licensed under GNU GPL v2
For bug reports, read
        http://openocd.org/doc/doxygen/bugs.html
Info : auto-selecting first available session transport "jtag". To override use 'transport select <transport>'.
Info : Listening on port 6666 for tcl connections
Info : Listening on port 4444 for telnet connections
Info : J-Link V9 compiled Dec 30 2018 15:35:20
Info : Hardware version: 9.20
Info : VTarget = 3.229 V
Info : clock speed 1000 kHz
Info : JTAG tap: stm32f3x.cpu tap/device found: 0x3ba00477 (mfg: 0x23b (ARM Ltd), part: 0xba00, ver: 0x3)
Warn : JTAG tap: stm32f3x.cpu       UNEXPECTED: 0x3ba00477 (mfg: 0x23b (ARM Ltd), part: 0xba00, ver: 0x3)
Error: JTAG tap: stm32f3x.cpu  expected 1 of 1: 0x4ba00477 (mfg: 0x23b (ARM Ltd), part: 0xba00, ver: 0x4)
Info : JTAG tap: stm32f3x.bs tap/device found: 0x06414041 (mfg: 0x020 (STMicroelectronics), part: 0x6414, ver: 0x0)
Error: Trying to use configured scan chain anyway...
Warn : Bypassing JTAG setup events due to errors
Info : stm32f3x.cpu: hardware has 6 breakpoints, 4 watchpoints
Info : starting gdb server for stm32f3x.cpu on 3333
Info : Listening on port 3333 for gdb connections

Start gdb. There are some initialization commands in openocd.gdb in the project directory, which can be used directly to avoid manual input.

arm-none-eabi-gdb target/thumbv7m-none-eabi/debug/app -x openocd.gdb

The subsequent debugging method is the same as gdb.

{{o.name}}

{{m.name}}