pyOCD

pyOCD is an Open Source python library or programming and debugging ARM Cortex-M microcontrollers using CMSIS-DAP.

You can use the following interfaces:

1. From a python interpretor:

• halt, step, resume execution
• read/write memory
• read/write block memory
• read-write core register
• set/remove hardware breakpoints
• flash new binary
• reset

2. From a GDB client, you have all the features provided by gdb:

• load a .elf file
• read/write memory
• read/write core register
• set/remove hardware breakpoints
• high level stepping
• ...

Dependencies

pyOCD relies on external libraries:

• Windows: pyWinUSB:

$ cd /path-to-pywinusb/
$ python setup.py install

• Linux: pyUSB:

$ sudo apt-get install python libusb-1.0-0-dev
$ cd /path-to-pyusb/
$ sudo python setup.py install

• Mac: So far Mac OS X is not supported

Installation

$ cd /path-to-pyOCD/
$ python setup.py install

Standalone GDB Server

pyOCD now provide a manual HOW_TO_BUILD.md in root folder to explain how to build pyOCD into single executable gdb server program.

[GCC ARM Toolchain](https://launchpad.net/gcc-arm-embedded) also provided a pre-build version of pyOCD gdb server at [Misc tools related to gcc arm embedded tool chain](https://launchpad.net/gcc-arm-embedded-misc/pyocd-binary)

Examples

Tests

A series of tests are on the test directory:

• basic_test.py: simple test that checks:
  • read/write core registers
  • read/write memory
  • stop/resume/step the execution
  • reset the target
  • flash a binary
• gdb_test.py: launch a gdbserver
• gdb_server.py: an enhanced version of gdbserver which provides the following options:
  • "-p", "--port", help = "Write the port number that GDB server will open"
  • "-b", "--board", help = "Write the board id you want to connect"
  • "-l", "--list", help = "List all the connected board"
  • "-d", "--debug", help = "Set the level of system logging output, the available value for DEBUG_LEVEL: debug, info, warning, error, critical"

Hello World example

from pyOCD.board import MbedBoard

import logging
logging.basicConfig(level=logging.INFO)

board = MbedBoard.chooseBoard()

target = board.target
flash = board.flash
target.resume()
target.halt()

print "pc: 0x%X" % target.readCoreRegister("pc")
    pc: 0xA64

target.step()
print "pc: 0x%X" % target.readCoreRegister("pc")
    pc: 0xA30

target.step()
print "pc: 0x%X" % target.readCoreRegister("pc")
   pc: 0xA32

flash.flashBinary("binaries/l1_lpc1768.bin")
print "pc: 0x%X" % target.readCoreRegister("pc")
   pc: 0x10000000

target.reset()
target.halt()
print "pc: 0x%X" % target.readCoreRegister("pc")
   pc: 0xAAC

board.uninit()

###GDB server example Python:

from pyOCD.gdbserver import GDBServer
from pyOCD.board import MbedBoard

import logging
logging.basicConfig(level=logging.INFO)

board = MbedBoard.chooseBoard()

# start gdbserver
gdb = GDBServer(board, 3333)

gdb server:

arm-none-eabi-gdb basic.elf

<gdb> target remote localhost:3333
<gdb> load
<gdb> continue

Architecture

Interface

An interface does the link between the target and the computer. This module contains basic functionalities to write and read data to and from an interface. You can inherit from Interface and overwrite read(), write(),...

Then declare your interface in INTERFACE (in pyOCD.interface.__init__.py)

Target

A target defines basic functionalities such as step, resume, halt, readMemory,... You can inherit from Target to implement your own methods.

Then declare your target in TARGET (in pyOCD.target.__init__.py)

Transport

Defines the transport used to communicate. In particular, you can find CMSIS-DAP. Implements methods such as memWriteAP, memReadAP, writeDP, readDP, ...

You can inherit from Transport and implement your own methods. Then declare your transport in TRANSPORT (in pyOCD.transport.__init__.py)

Flash

Contains flash algorithm in order to flash a new binary into the target.

gdbserver

Start a GDB server. The server listens on a specific port. You can then connect a GDB client to it and debug/program the target

Then you can debug a board which is composed by an interface, a target, a transport and a flash