Python Based ARM CoreSight Debug and Trace Tools

• PyCS is a python based JTAG/SWD debugger for ARM chips.
• Its current focus is systems using Cortex-M ARM CPUs.
• It reads the SoC SVD files to give full peripheral/register decodes for a wide variety of Cortex-M based chips.

• A PC with Python3 installed (Host System)
• A target system with a Cortex-M ARM cpu (Targets)
• An SWD debug interface (Debug Interface)

• Run "make" - this will build the ARM disassembler library.
• Run "./pycs" in the same directory you extracted the code to.
• If you don't have permissions to access USB devices you can fix that (with a udev rules file) or run with "sudo ./pycs"

$ ./pycs -l
supported targets:
  axoloti       : Axoloti Synth Board (STM32F427xG)
  efm32lg       : EFM32 Leopard Gecko Starter Kit (EFM32LG990F256)
  frdm_k64f     : FRDM-K64F Kinetis Development Board (MK64FN1M0VLL12)
  mb1035b       : STM32F3 Discovery Board (STM32F303xC)
  mb1075b       : STM32F4 Discovery Board (STM32F429xI)
  mb997c        : STM32F4 Discovery Board (STM32F407xx)
  nRF51822      : Adafruit BLE USB dongle (nRF51822)
  nRF52dk       : Nordic nRF52DK Development Board (nRF52832)
  nucleo-l432kc : Nucleo-L432KC (STM32L432KC)
  saml21        : Atmel SAM L21 Xplained Pro Evaluation Board (ATSAML21J18B)
  tepo          : Teenage Engineering Pocket Operator (EFM32LG890F128)

• sudo apt-get install python3-lxml
• sudo apt-get install python3-hid

$ ./pycs -t mb997c

pycs: ARM CoreSight Tool 1.0
STM32F407xx: compiling ./vendor/st/svd/STM32F40x.svd.gz
ST-Link usb 0483:3748 serial u"H\xffj\x06PuIU'3\x04\x87"
target voltage 2.889V

mb997c*>

It has an interactive CLI.

• '?' for menu help
• '?' for command completion/argument help
• TAB for command completion
• 'help' for general help

• display memory
• disassemble memory
• display system control registers
• display peripheral registers
• halt/go the cpu
• program flash
• Segger RTT client
• measure counter frequencies
• etc. etc.

• HOWTO hookup development boards