pyDAPLink

pyDAPLink is an Open Source python 2.7 library for communicating with ARM Cortex-M microcontrollers through CMSIS-DAP over USB. Currently Linux, OSX, and Windows are supported.

For more information on CMSIS-DAP you can find the official standard:

https://silver.arm.com/browse/CMSISDAP

Installation

To install the latest development version (master branch), you can do the following:

$ pip install --pre -U https://github.com/<user>/pyDAPLink/archive/master.zip

Note that you may run into permissions issues running these commands.

You have a few options here:

1. Run with sudo -H to install pyDAPLink and dependencies globally
2. Specify the --user option to install local to your user
3. Run the command in a virtualenv local to a specific project working set.

You can also install from source by cloning the git repository and running

$ python setup.py install

Development Setup

PyDAPLink developers are recommended to setup a working environment using virtualenv. After cloning the code, you can setup a virtualenv and install the PyDAPLink dependencies for the current platform by doing the following:

$ virtualenv env
$ source env/bin/activate
$ pip install -r dev-requirements.txt

On Windows, the virtualenv would be activated by executing env\Scripts\activate.

Examples

For a more in depth example you can look into pyDAPLink's usage in pyOCD:

https://github.com/<user>/pyOCD

Hello World example program

from pyDAPLink import DAPLink
from pyDAPLink import AP_REG, DP_REG

# Some device specific definitions are needed
MBED_VID = 0x0d28
MBED_PID = 0x0204
CORTEXM_DHCSR = 0xE000EDF0
CORTEXM_DCRSR = 0xE000EDF4
CORTEXM_DCRDR = 0xE000EDF8
DBG_KEY = 0xA05F0000
DBG_ENABLE = 0x1
DBG_HALT = 0x2

# Find all connected devices
interfaces = DAPLink.getConnectedInterfaces(MBED_VID, MBED_PID)

for interface in interfaces:
    # Create a CMSIS-DAP connection
    dap = DAPLink(interface)
    dap.init()

    # Read ID code
    print 'ID: 0x%08x' % dap.readAP(AP_REG['IDR'])

    # Halt a Cortex-M
    dap.writeMem(CORTEXM_DHCSR, DBG_KEY | DBG_ENABLE | DBG_HALT)

    # Read a Cortex-M's PC
    dap.writeMem(CORTEXM_DCRSR, 15)
    print 'PC: 0x%08x' % dap.readMem(CORTEXM_DCRDR)

    dap.uninit()