184 lines
9.3 KiB
Markdown
184 lines
9.3 KiB
Markdown
# EK-TM4C1294XL Connected LaunchPad flexPTP demo
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## What's this?
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> **This is a [flexPTP](https://github.com/epagris/flexPTP) demo project showcasing the capabilities of the flexPTP [IEEE 1588 Precision Time Protocol](https://ieeexplore.ieee.org/document/9120376) implementation for the [Texas Instruments EK-TM4C1294XL Connected LaunchPad](https://www.ti.com/tool/EK-TM4C1294XL) devboard.**
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Still not clear what is it useful for? No worries, it's a behind-the-scenes support technology that use unaware every day if you have a smartphone or when you are connected to the internet. Modern telecommunication and measurement systems often rely on precise time synchronization down to the nanoseconds' scale. Methods got standardized by the IEEE and now it's known by the name of the Precision Time Protocol. This software project is an evaluation environment to showcase the capabilities of our IEEE 1588 PTP implementation named `flexPTP` on the Texas Instruments EK-TM4C1294XL Connected LaunchPad board.
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> [!TIP]
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>**Just want to try the demo and skip compiling? Download one of the precompiled binaries and jump to [Deploying](#deploying)!**
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### Get the sources
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> [!NOTE]
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> To acquire the full source tree after cloning the repo, please fetch the linked *submodules* as well:
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```
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git clone https://gitea.epagris.com/epagris/flexPTP-demo-TM4C1294.git
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cd flexPTP-demo-TM4C1294
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git submodule init
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git submodule update
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```
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## Building
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### Prerequisites
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The following two pieces of software are necessary for building:
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- `arm-none-eabi-gcc` (v12+): the GCC ARM Cortex-M C cross-compiler
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- `cmake` (v3.22+): KitWare's build management system
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> [!NOTE]
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> Both applications are available on common Linux systems through the official package repository. Although it's a Texas Instruments product, for building on Windows we recommend to install the STMicroelectronics [STM32CubeCLT](https://www.st.com/en/development-tools/stm32cubeclt.html) bundle shipping the `arm-none-eabi-{gcc|gdb}`, `openocd`. The [CMake](https://cmake.org/) needs to be installed separately.
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### Compiling
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The project is fully CMake managed. Configure and invoke the cross-compiler using the commands below:
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```
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cmake . -B build
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cmake --build build --target flexptp-tiva --
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```
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Once the building has concluded the output binaries would be deposited in the `build` directory: `flexptp-tiva.elf`, `flexptp-tiva.bin`, `flexptp-tiva.hex`
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## Deploying
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### Downloading the firmware
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The compiled binaries can be downloaded onto the devboard through several tools:
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### Using the `lm4flash` utility
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This tool is part of the open source [lm4flash](https://github.com/utzig/lm4tools) bundle, that is also available through common Linux package managers.
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To program the MCU use the following command: `lm4flash build/flexptp-tiva.bin`
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### Using the `openocd` application
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The [OpenOCD](https://openocd.org/) programming/debugging tool can also be used to upload the firmware using the following command:
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`openocd -f "board/ti_ek-tm4c1294xl.cfg" -c init -c halt -c "program build/flexptp-tiva.elf" -c exit`
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OpenOCD is also available through the common Linux package managers.
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### Interacting with the firmware
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The firmware prints its messages to and expect user input coming on the board controller's virtual serial port using the `115200-8-N-1` configuration. Use [Putty](https://www.putty.org/) or any equivalent (e.g. GtkTerm) serial port terminal to communicate with the firmware. On Linux, the device will show up as `/dev/ttyACMx`.
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> [!NOTE]
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> Read the firmware's bootup hints and messages carefully!
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### PPS signal
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The 1PPS signal is emitted on the `PG0` pin.
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## Development
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An all-around [Visual Studio Code](https://code.visualstudio.com/) project is packaged along the project to enable easy development, debugging and editing. To enable these powerful features, [CMakeTools](https://marketplace.visualstudio.com/items?itemName=ms-vscode.cmake-tools), [Cortex-Debug](https://marketplace.visualstudio.com/items?itemName=marus25.cortex-debug), [Embedded Tools](https://marketplace.visualstudio.com/items?itemName=ms-vscode.vscode-embedded-tools) extensions and the [OpenOCD](https://openocd.org/) software package. [clangd](https://marketplace.visualstudio.com/items?itemName=llvm-vs-code-extensions.vscode-clangd) and clang-format are highly recommended.
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Thas project has predefined *Launch* and *Attach* tasks.
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### Software structure
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The project is relying on the following large software building blocks:
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- the [FreeRTOS](https://www.freertos.org/) embedded operating system,
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- the [CMSIS RTOS V2](https://arm-software.github.io/CMSIS_6/latest/RTOS2/index.html) module as a wrapper for FreeRTOS,
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- the [TivaWare](https://github.com/antoinealb/Tivaware) peripheral library,
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- the [Lightweight IP](https://github.com/lwip-tcpip/lwip) (lwip) Ethernet stack extended with PTP timestamp support,
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- the [embfmt](https://gitea.epagris.com/epagris/embfmt) a printf()-like formatted printer implementation for embedded systems.
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The project is organized the following way:
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```
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ROOT
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Drivers
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CMSIS: ARM CMSIS-related files (CMSIS RTOS V2 and device headers)
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tivaware: TI's peripheral library (submodule)
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Inc: headers for compile-time library configuration
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Middlewares: FreeRTOS CMake configuration
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Modules
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flexptp: our PTP implementation (submodule)
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lwip: the LwIP Ethernet stack (submodule)
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lwip_port: network interface and system specific implementations
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embfmt: a printf()-like formatted printer implementation for embedded systems (submodule)
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Src
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utils: TI-provided utilities
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task_eth.c: Ethernet stack management
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cli.c/h: CLI-interface implementation
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cmds.c: custom CLI commands
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```
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> [!NOTE]
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> The flexPTP parameters are defined in the [flexptp_options.h](Inc/flexptp_options.h) header.
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> [!NOTE]
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> The low-level Ethernet network driver is located in the [tiva-tm4c129.c](Modules/lwip_port/tiva-tm4c129/netif/tiva-tm4c129.c) file.
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### Printing and logging
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In this project the memory-heavy `printf()` is replaced by the more embedded-optimized `MSG()` function backed by the `embfmt` library. Parameters and format specifiers are fully `printf()` compatible.
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### CLI commands
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The software offers you with the following multitude, most flexPTP-related of commands:
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```
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? Print this help (22/48)
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hist Print command history
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osinfo Print OS-related information
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flexptp Start flexPTP daemon
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ptp servo params [Kp Kd] Set or query K_p and K_d servo parameters
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ptp servo log internals {on|off} Enable or disable logging of servo internals
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ptp reset Reset PTP subsystem
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ptp servo offset [offset_ns] Set or query clock offset
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ptp log {def|corr|ts|info|locked|bmca} {on|off} Turn on or off logging
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time [ns] Print time
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ptp master [[un]prefer] [clockid] Master clock settings
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ptp info Print PTP info
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ptp domain [domain] Print or get PTP domain
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ptp addend [addend] Print or set addend
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ptp transport [{ipv4|802.3}] Set or get PTP transport layer
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ptp delmech [{e2e|p2p}] Set or get PTP delay mechanism
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ptp transpec [{def|gPTP}] Set or get PTP transportSpecific field (majorSdoId)
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ptp profile [preset [<name>]] Print or set PTP profile, or list available presets
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ptp tlv [preset [name]|unload] Print or set TLV-chain, or list available TLV presets
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ptp pflags [<flags>] Print or set profile flags
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ptp period <delreq|sync|ann> [<lp>|matched] Print or set log. periods
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ptp coarse [threshold] Print or set coarse correction threshold
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ptp priority [<p1> <p2>] Print or set clock priority fields
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```
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> [!TIP]
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> The above hint can be listed by typing '?'.
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## Notes
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> [!WARNING]
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> By default, the MCU clock is sourced by the onboard (STLink) board controller on this devboard. According to our observations, this clock signal is loaded with heavy noise rendering the clock synchronization unable to settle precisely. We highly recommend to solder a 8 MHz oscillator onto the designated X3 pads to achieve the best results!
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## Related papers and references
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[Time Synchronization Extension for the IO-Link Industrial Communication Protocol](https://ieeexplore.ieee.org/document/10747727)
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[Distributed Measurement System for Performance Evaluation of Embedded Clock Synchronization Solutions](https://ieeexplore.ieee.org/document/9805958/)
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[Portable, PTP-based Clock Synchronization Implementation for Microcontroller-based Systems and its Performance Evaluation](https://ieeexplore.ieee.org/document/9615250)
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[Synchronization of Sampling in a Distributed Audio Frequency Range Data Acquisition System Utilizing Microcontrollers](https://ieeexplore.ieee.org/document/9918455/)
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[Methods of Peripheral Synchronization in Real-Time Cyber-Physical Systems](https://ieeexplore.ieee.org/document/10178979/)
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## License
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The project is created by András Wiesner (Epagris) in 2025 and published under the MIT license. Contributions are welcome! :)
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