Solve the problem that openocd fails to burn STM32 and cannot connect through SWD

OpenOCD burn STM32 Failure problem

Linux Next use OpenOCD burn STM32, There is Error: init mode failed (unable to connect to the target) error .

If in code , Carelessly PA13,PA14 Of SWD Function off , For example, the following code is used

rcc_periph_clock_enable(RCC_GPIOA);         // Need GPIOA clock
gpio_primary_remap(
    AFIO_MAPR_SWJ_CFG_JTAG_OFF_SW_OFF,      // Optional
    AFIO_MAPR_TIM2_REMAP_NO_REMAP);         // This is default: TIM2.CH2=GPIOA1

Or in STM32CubeMX Forget to check in PA13/PA14 Serial port debugging function , Will cause subsequent burning and connection failure , appear

Uploading .pio/build/bluepill_f103c8/firmware.elf
xPack OpenOCD x86_64 Open On-Chip Debugger 0.11.0+dev (2021-10-16-21:15)
Licensed under GNU GPL v2
For bug reports, read
        http://openocd.org/doc/doxygen/bugs.html
debug_level: 1

hla_swd
none separate

Error: init mode failed (unable to connect to the target)
in procedure 'program'
** OpenOCD init failed **
shutdown command invoked

*** [upload] Error 1

STLINK Tools st-flash and st-info

First, check whether there is st-flash and st-info command , If not, it needs to be installed

Installation steps

git clone https://github.com/stlink-org/stlink.git
cd stlink/
make
#  If the  libusb  error ,  Just install it  libusb-1.0-0-dev,  Again make
sudo apt install libusb-1.0-0-dev
make clean
make
cd build/Release/
sudo make install

adopt st-info Check You will be prompted that you cannot enter SWD Pattern

$ st-info --probe
Failed to parse flash type or unrecognized flash type
Failed to enter SWD mode
Found 1 stlink programmers
  version:    V2J37S7
  serial:     56FF6B064966485627161123
  flash:      0 (pagesize: 0)
  sram:       0
  chipid:     0x000

detected chip_id parametres

# Device Type: unknown
# Reference Manual: RM0000
#
chip_id 0x0
flash_type 0
flash_size_reg 0x0
flash_pagesize 0x0
sram_size 0x0
bootrom_base 0x0
bootrom_size 0x0
option_base 0x0
option_size 0x0
flags 0

  dev-type:   unknown

Use st-flash and st-info solve STM32 Burning failed

Most of the schemes found on the Internet , For example, this stackoverflow The answer to , It's all about getting there Windows Next , adopt ST-link utility Go to reset erase , Here is an introduction Linux Treatment method under

st-info Use --connect-under-reset Parameters

You need to use --connect-under-reset Parameters , Press and hold the development board RESET After the key , Execute the following command , The chip information can be correctly detected

$ st-info --probe  --connect-under-reset
Failed to parse flash type or unrecognized flash type

detected chip_id parametres

# Device Type: STM32F1xx_MD
# Reference Manual: RM0008
#
chip_id 0x410
flash_type 1
flash_size_reg 0x1ffff7e0
flash_pagesize 0x400
sram_size 0x5000
bootrom_base 0x1ffff000
bootrom_size 0x800
option_base 0x1ffff800
option_size 0x10
flags 2

Found 1 stlink programmers
  version:    V2J37S7
  serial:     56FF6B064966485627161123
  flash:      0 (pagesize: 1024)
  sram:       20480
  chipid:     0x410

detected chip_id parametres

# Device Type: STM32F1xx_MD
# Reference Manual: RM0008
#
chip_id 0x410
flash_type 1
flash_size_reg 0x1ffff7e0
flash_pagesize 0x400
sram_size 0x5000
bootrom_base 0x1ffff000
bootrom_size 0x800
option_base 0x1ffff800
option_size 0x10
flags 2

  dev-type:   STM32F1xx_MD

If that's the case , That is the PA13/PA14 Function reuse of , The problem can be solved by firmware erasure

st-flash Erase firmware

st-flash Similarly, add --connect-under-reset Competition , Press and hold RESET Key and execute the following command

$ st-flash --connect-under-reset erase
st-flash 1.7.0-184-g468b1d2
Failed to parse flash type or unrecognized flash type
2022-02-14T22:51:20 ERROR common.c: Soft reset failed: timeout

detected chip_id parametres

# Device Type: STM32F1xx_MD
# Reference Manual: RM0008
#
chip_id 0x410
flash_type 1
flash_size_reg 0x1ffff7e0
flash_pagesize 0x400
sram_size 0x5000
bootrom_base 0x1ffff000
bootrom_size 0x800
option_base 0x1ffff800
option_size 0x10
flags 2

2022-02-14T22:51:20 INFO common.c: STM32F1xx_MD: 20 KiB SRAM, 0 KiB flash in at least 1 KiB pages.
Mass erasing

In the presence of Mass erasing after , The power cannot be cut off immediately , It's going to take a little while , After use st-info --probe Check for success , If it still shows Failed to enter SWD mode, Just repeat the above operation again .

If st-info --probe Can directly detect the chip , Just explain SWD The function has been restored , Can continue in Linux Next use OpenOCD Burn happily STM32 了 .