pyocd
Cortex-M debugger for Python
Decision gist · record as of 2026-08-14
Yes. pyOCD is actively maintained, has low install friction, carries no security vulnerabilities, and is licensed permissively. It is the right choice if you need a Python-native, cross-platform debugger for Cortex-M development or CI automation. The only prerequisite is a supported debug probe and libusb; if you have those, installation and basic use are straightforward.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires libusb and a supported debug probe (CMSIS-DAP, J-Link, STLink, etc.) connected via USB.
- Python 3.9.0 or later required.
- Low install friction with a pure-Python wheel and 17 runtime dependencies that are widely available.
License · maintenance · safety
Apache 2.0 (permissive) — Apache 2.0 is permissive, allowing commercial and private use without restriction or copyleft obligation.
last release 2026-07-21 (24 days) · last repo commit 2026-07-24 · 1,443 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 1,372,352 downloads/mo, #3,991 on PyPI
Alternatives
Verify before relying
pip install pyocd
from pyocd.core.target import Target
from pyocd.probe.pydaplink import DAPLink
probe = DAPLink.get_connected_probes()[0]
target = Target(probe.create_target())
target.halt()
memory = target.read_memory(0x0, 4)
target.resume()- Whether the 70+ built-in MCU support claim is current or if that list has grown since v0.45.1.
- Specific performance characteristics when handling large binary or ELF files during flash programming.
- Compatibility matrix detail for all listed debug probes across different OS versions.
What it is and what it does
pyOCD is a cross-platform Python tool and library for programming and debugging Arm Cortex-M microcontrollers using a wide range of debug probes. It provides both a command-line interface with subcommands for common tasks (gdbserver, load, erase, reset, rtt, etc.) and a Python API for custom control and automation. The tool supports more than 70 popular MCUs natively and can extend support through CMSIS Device Family Packs to cover nearly every Cortex-M device on the market.
The package is built on 17 runtime dependencies including capstone for disassembly, hidapi and pyusb for USB communication, pyelftools for ELF parsing, and cmsis-pack-manager for device pack handling. It offers memory read/write, register access, breakpoint and watchpoint management, flash programming, binary/hex/ELF file loading, SWO/SWV support, and CoreSight DP/AP access. Configuration is supported through config files, user scripts, and direct API use, making it suitable for both interactive debugging and CI/CD test automation.
Use it for
- Debug Arm Cortex-M firmware interactively using gdb via the gdbserver subcommand with GUI debugger support.
- Automate flash programming and testing in CI pipelines by loading binaries and controlling device execution via the Python API.
- Stream Segger RTT I/O from any supported debug probe without needing vendor-specific tools.
- Inspect and modify MCU memory and registers in real time using the commander interactive REPL.
- Program multiple MCU variants by managing CMSIS Device Family Packs for devices without built-in support.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes.
pyOCD is actively maintained, has low install friction, carries no security vulnerabilities, and is licensed permissively. It is the right choice if you need a Python-native, cross-platform debugger for Cortex-M development or CI automation. The only prerequisite is a supported debug probe and libusb; if you have those, installation and basic use are straightforward.
Install
pyocd on PyPI
Before you install
Low install friction with a pure-Python wheel and 17 runtime dependencies that are widely available. Active maintenance with a release 24 days ago and ongoing repository activity.
Requires libusb and a supported debug probe (CMSIS-DAP, J-Link, STLink, etc.) connected via USB. Python 3.9.0 or later required.
License in practice
Apache 2.0 is permissive, allowing commercial and private use without restriction or copyleft obligation.
Quickstart
pip install pyocd
from pyocd.core.target import Target
from pyocd.probe.pydaplink import DAPLink
probe = DAPLink.get_connected_probes()[0]
target = Target(probe.create_target())
target.halt()
memory = target.read_memory(0x0, 4)
target.resume()Verify before relying
- Whether the 70+ built-in MCU support claim is current or if that list has grown since v0.45.1.
- Specific performance characteristics when handling large binary or ELF files during flash programming.
- Compatibility matrix detail for all listed debug probes across different OS versions.
Package facts
| License | Apache 2.0 permissive |
| Python support | Supports the current Python release >=3.9.0 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 17 packagescapstonecmsis-pack-managercoloramahidapiimportlib_metadataimportlib_resourcesintelhexintervaltreelarklibusb-packagenatsortprettytablepyelftoolspylink-squarepyusbpyyamltyping-extensions |
| Maintenance | Actively maintained 24 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 1,372,352 / month, #3,991 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableEnvironment :: ConsoleIntended Audience :: DevelopersIntended Audience :: ManufacturingIntended Audience :: Science/ResearchLicense :: OSI Approved :: Apache Software LicenseOperating System :: MacOS :: MacOS XOperating System :: Microsoft :: WindowsOperating System :: POSIXOperating System :: POSIX :: BSDOperating System :: POSIX :: LinuxProgramming Language :: PythonProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Programming Language :: Python :: 3.9Topic :: Software DevelopmentTopic :: Software Development :: DebuggersTopic :: Software Development :: Embedded SystemsTopic :: Software Development :: TestingTopic :: Utilities |
Evidence: pyocd-0.45.1-py3-none-any.whl
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See also pyocd-pemicro · spsdk-pyocd · pyudev · pypemicro · pylink-square · freertos-gdb · pygdbmi · Adafruit-Blinka · libusbsio · spsdk-mcu-link