st-link connection loss problem or system reset?

Sguo.19 · ‎2020-01-27

I am using nucleo board with stm32l476rg for development. I found that under debugging mode, the program will reset itself and stlink will lose connection. I am not sure if the program causes the reset or the st-link causes the reset. Even I did not open the truestudio for debugging, the same thing happens and reset is observed.

I used a very simple program with only USB supported and running on an infinite loop waiting for usb commands. Even without any operations, the same thing will happen, which is about 5-10 mins. If I keep feeding usb commands, it seems OK.

Anyone can kindly give me some hints on this? I got stucked. Thank you so much.

Below is the logging:

STM32 device: flash programming successful 0x80313e8

Flash write completed in 0.220000 seconds, 2.592330kB/s

Enter STM32_AppReset() function

NVIC_DFSR_REG = 0x00000009

NVIC_CFGFSR_REG = 0x00000000

XPSR = 0x01000000

Reading 0x2 bytes of memory from addr 0x802acc8

Reading 0x4 bytes of memory from addr 0x802ec50

Reading 0x4 bytes of memory from addr 0xe0042004

Reading 0x4 bytes of memory from addr 0x802ec50

Reading 0x2 bytes of memory from addr 0x802acc8

TraceCaptureStart and SWV event set to APP_TRUE

ST_LINK device status: RUN_MODE

ST_LINK device status: HALT_MODE

TraceCaptureStart and SWV event set to APP_FALSE

NVIC_DFSR_REG = 0x00000002

ST_LINK Halt Reason break point hit

Reading 0x4 bytes of memory from addr 0x802acc8

Reading 0x4 bytes of memory from addr 0xe000ed04

Reading 0x4 bytes of memory from addr 0xe000ed2c

Reading 0x4 bytes of memory from addr 0xe000ed28

Reading 0x4 bytes of memory from addr 0xe000ed38

Reading 0x4 bytes of memory from addr 0xe000ed34