This code example illustrates how to implement a programmable power supply (PPS) sink using the EZ-PD™ PMG1 MCU devices.
The EZ-PD™ PMG1 MCU establishes a PPS sink contract with a USB-C power adapter capable of PPS, and the device subsequently requests a voltage range from the minimum to maximum VBUS voltage supported by the adjustable power delivery object (APDO). This voltage is adjusted in increments of 100 mV, starting with the minimum advertised current. When the device reaches the maximum VBUS voltage, it begins to decrease the voltage in 100 mV steps until it reaches the minimum voltage, while maintaining the minimum current.
Provide feedback on this code example.
- ModusToolbox™ v3.1 or later (tested with v3.1)
- Board support package (BSP) minimum required version: 3.1.0
- Programming language: C
- Associated parts: All EZ-PD™ PMG1 MCU parts
- PPS capable USB-C adapter
- (Optional) Multimeter / PD analyzer / oscilloscope to observe the USB PD supply voltage VBUS
- GNU Arm® Embedded Compiler v11.3.1 (
GCC_ARM) - Default value ofTOOLCHAIN - Arm® Compiler v6.16 (
ARM) - IAR C/C++ Compiler v9.30.1 (
IAR)
- EZ-PD™ PMG1-S0 Prototyping Kit (
PMG1-CY7110) - Default value ofTARGET - EZ-PD™ PMG1-S1 Prototyping Kit (
PMG1-CY7111) - EZ-PD™ PMG1-S2 Prototyping Kit (
PMG1-CY7112) - EZ-PD™ PMG1-S3 Prototyping Kit (
PMG1-CY7113)
This example uses the board's default configuration. See the kit user guide to ensure that the board is configured correctly.
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Connect the board to your PC using the USB cable through the KitProg3 Type-C connector (J1). This cable is used for programming and debugging the EZ-PD™ PMG1 device.
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Connect the USB PD port to the PPS capable USB-C power adapter using the USB Type-C cable. This cable is used for the USB power delivery source and it provides power to the user LED.
Install a terminal emulator if you don't have one. Instructions in this document use Tera Term.
This example requires no additional software or tools.
The ModusToolbox™ tools package provides the Project Creator as both a GUI tool and a command line tool.
Use Project Creator GUI
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Open the Project Creator GUI tool. There are several ways to do this, including launching it from the dashboard or from inside the Eclipse IDE. For more details, see the Project Creator user guide (locally available at {ModusToolbox™ install directory}/tools_{version}/project-creator/docs/project-creator.pdf).
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On the Choose Board Support Package (BSP) page, select a kit supported by this code example. See Supported kits.
Note: To use this code example for a kit not listed here, you may need to update the source files. If the kit does not have the required resources, the application may not work.
- On the Select Application page: a. Select the Applications(s) Root Path and the Target IDE.
Note: Depending on how you open the Project Creator tool, these fields may be pre-selected for you.
b. Select this code example from the list by enabling its check box.
Note: You can narrow the list of displayed examples by typing in the filter box.
c. (Optional) Change the suggested New Application Name and New BSP Name.
d. Click Create to complete the application creation process.
Use Project Creator CLI
The 'project-creator-cli' tool can be used to create applications from a CLI terminal or from within batch files or shell scripts. This tool is available in the {ModusToolbox™ install directory}/tools_{version}/project-creator/ directory.
Use a CLI terminal to invoke the 'project-creator-cli' tool. On Windows, use the command-line 'modus-shell' program provided in the ModusToolbox™ installation instead of a standard Windows command-line application. This shell provides access to all ModusToolbox™ tools. You can access it by typing "modus-shell" in the search box in the Windows menu. In Linux and macOS, you can use any terminal application.
The following example clones the "USB PD Sink PPS Demo" application with the desired name "MyUsbPdSinkPPSDemo" configured for the PMG1-CY7110 BSP into the specified working directory, C:/mtb_projects:
project-creator-cli --board-id PMG1-CY7110 --app-id mtb-example-pmg1-usbpd-sink-pps --user-app-name MyUsbPdSinkPPSDemo --target-dir "C:/mtb_projects"
The 'project-creator-cli' tool has the following arguments:
| Argument | Description | Required/optional |
|---|---|---|
--board-id |
Defined in the field of the BSP manifest | Required |
--app-id |
Defined in the field of the CE manifest | Required |
--target-dir |
Specify the directory in which the application is to be created if you prefer not to use the default current working directory | Optional |
--user-app-name |
Specify the name of the application if you prefer to have a name other than the example's default name | Optional |
Note: The project-creator-cli tool uses the
git cloneandmake getlibscommands to fetch the repository and import the required libraries. For details, see the "Project creator tools" section of the ModusToolbox™ tools package user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mtb_user_guide.pdf).
After the project has been created, you can open it in your preferred development environment.
Eclipse IDE
If you opened the Project Creator tool from the included Eclipse IDE, the project will open in Eclipse automatically. For more details, see the Eclipse IDE for ModusToolbox™ user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mt_ide_user_guide.pdf).
Visual Studio (VS) Code
Launch VS Code manually, and then open the generated {project-name}.code-workspace file located in the project directory. For more details, see the Visual Studio Code for ModusToolbox™ user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mt_vscode_user_guide.pdf).
Keil µVision
Double-click the generated {project-name}.cprj file to launch the Keil µVision IDE. For more details, see the Keil µVision for ModusToolbox™ user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mt_uvision_user_guide.pdf).
IAR Embedded Workbench
Open IAR Embedded Workbench manually, and create a new project. Then select the generated {project-name}.ipcf file located in the project directory. For more details, see the IAR Embedded Workbench for ModusToolbox™ user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mt_iar_user_guide.pdf).
Command line
If you prefer to use the CLI, open the appropriate terminal, and navigate to the project directory. On Windows, use the command-line 'modus-shell' program; on Linux and macOS, you can use any terminal application. From there, you can run various make commands.
For more details, see the ModusToolbox™ tools package user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mtb_user_guide.pdf).
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Ensure that the steps listed in the Hardware setup section are complete.
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Ensure that the jumper shunt on power selection jumper (J5) is placed at position 2-3 (VIN) while programming the kit.
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Program the board using one of the following:
Using Eclipse IDE for ModusToolbox™
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Select the application project in the Project Explorer.
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In the Quick Panel, scroll down, and click <Application Name> Program (KitProg3_MiniProg4).
Using CLI
From the terminal, execute the
make programcommand to build and program the application using the default toolchain to the default target. The default toolchain and target are specified in the application's Makefile but you can override those values manually:make program TOOLCHAIN=<toolchain>Example:
make program TOOLCHAIN=GCC_ARM -
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After programming the kit, change the position on power selection jumper (J5) to 1-2 (VBUS).
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Connect a PPS source to USB PD Port (J10).
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EZ-PD™ PMG1 device (sink) reads the source capabilities advertised by the PPS source and parses the programmable power supply (PPS) power data object (PDO)s and finds out the minimum voltage, maximum voltage and minimum current
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EZ-PD™ PMG1 device (sink) makes a contract with the PDOs which offers higher power.
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If source is capable of supporting PPS,
- After 1 second, EZ-PD™ PMG1 device (sink) makes a PPS 5V contract with the PPS source. Negotiated voltage can be measured across the DC_OUT terminal (J9) using the multimeter or oscilloscope.
- If PPS contract is made, user LED blinks at about 1Hz (toggles every 500ms).
- EZ-PD™ PMG1 device (sink) starts requesting for PPS minimum voltage with minimum current to the PPS source after 500 ms.
- EZ-PD™ PMG1 device (sink) renegotiates with an incremental voltage in steps of 100 mV with minimum current for every 500 ms.
- After voltage reaches maximum, EZ-PD™ PMG1 device (sink) renegotiates with a decremental voltage in steps of 100 mV with minimum current for every 500 ms.
- After voltage reaches minimum, EZ-PD™ PMG1 device (sink) renegotiates with an incremental voltage. This happens in loop.
Figure 1. Voltage graph
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If the source does not support PPS. User LED glows indicating that PPS contract is not made.
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Pressing user switch sends "Get_PPS_Status" PD message to PPS source. PPS source replies with "PPS_Status" PD message to EZ-PD™ PMG1 MCU device (sink). PD packets can be seen using EZ-PD™ Protocol Analyzer.
Note: The CY4500 EZ-PD™ Protocol Analyzer tool records traffic passively on the Configuration Channel (CC) and allows users to analyze and debug USB Power Delivery communication. The low-cost and compact CY4500 EZ-PD™ Protocol Analyzer acts as a pass-through for VBUS, VCONN, USB 3.1, USB 2.0 and USB-PD traffic.
You can debug the example to step through the code.
In Eclipse IDE
Use the <Application Name> Debug (KitProg3_MiniProg4) configuration in the Quick Panel.
Ensure that the board is connected to your PC using the USB cables through both the KitProg3 USB connector as well as the USB PD port, with the jumper shunt on power selection jumper (J5) placed at position 1-2. For details, see the "Program and debug" section in the Eclipse IDE for ModusToolbox™ user guide.
In other IDEs
Follow the instructions in your preferred IDE.
EZ-PD™ PMG1 MCU devices support a USB PD block which integrates Type-C terminations, comparators, and the Power Delivery transceiver required to detect the attachment of a partner device and negotiate power contracts with it.
On reset, the USB PD block is initialized with the following settings:
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The receiver clock input of the block is connected to a 12-MHz PERI-derived clock.
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The transmitter clock input of the block is connected to a 600-kHz PERI-derived clock.
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The SAR ADC clock input of the block is connected to a 1-MHz PERI-derived clock.
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The SAR ADC in the USB PD block is configured to measure the VBUS_TYPE-C voltage through an internal divider.
This application uses the PDStack middleware library in an upstream facing port (UFP) - sink configuration. EZ-PD™ PMG1 MCU devices have a dead-battery Rd termination, which ensures that a USB-C source/charger connected to it can detect the presence of a sink even when the EZ-PD™ PMG1 MCU device is not powered.
Figure 2. Firmware flowchart
The PDStack middleware library configures the USB PD block on the EZ-PD™ PMG1 MCU device to detect Type-C connection state changes and USB PD messages, and notify the stack through callback functions. The callback function registers the pending tasks, which are then handled by PDStack through the Cy_PdStack_Dpm_Task function. This function is expected to be called at appropriate times from the main processing loop of the application.
Figure 3. PDStack task flowchart
The PDStack middleware library implements the state machines defined in the USB Type-C Cable and Connector and the USB Power Delivery specifications.
PDStack consists of the following main modules:
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Type-C manager: Responsible for detecting a Type-C connection and identifying the type of connection. It uses the configurable Rp/Rd terminations provided by the USB PD block and the internal line state comparators. The Type-C manager implements the state machines defined in the USB Type-C Cable and Connector specification and provides the following functionality:
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Manage CC terminations: Applies Rp/Rd terminations according to the port role
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Attach detection: Performs the required debounce and determines the type of device attached
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Detach detection: Monitors the CC line and VBus for detecting a device detach
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Protocol Layer: Forms the messages used to communicate between a pair of ports/cable plugs. It is responsible for forming capabilities messages, requests, responses, and acknowledgements. It receives inputs from the policy engine indicating which messages to send and relays the responses back to the policy engine.
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Policy engine: Provides a mechanism to monitor and control the USB Power Delivery system within a particular consumer, provider, or cable plug. It implements the state machines defined in the USB Power Delivery specification and contains implementations of all PD atomic message sequences (AMS). It interfaces with the protocol layer for PD message transmission/reception for controlling the reception of message types according conditions such as the current state of the port. It also interfaces with the Type-C manager for error conditions like Type-C error recovery.
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Device policy manager (DPM): Provides an interface to the application layer to initialize, monitor, and configure the PDStack middleware operation. The DPM provides the following functionality:
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Initialize the policy engine and Type-C manager
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Start the Type-C state machine followed by the policy engine state machine
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Stop and disable the Type-C port
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Allow entry/exit from deep sleep to achieve low power based on the port status
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Provide APIs for the application to send PD/Type-C commands
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Provide event callbacks to the application for application-specific handling
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The PDStack library uses a set of callbacks registered by the application to perform board-specific tasks such as turning the consumer power path ON/OFF and identifying the optimal source power profile to be used for charging. In this example, these functions are implemented using the appropriate APIs provided as part of the Peripheral Driver Library (PDL).
The stack also provides notification of various connection and PD policy state changes so that the rest of the system can be configured as required. These events are used by the example application to implement a separate USB Battery Charging 1.2 sink state machine, which distinguishes between a standard downstream port (SDP), charging downstream port (CDP), and dedicated charging port (DCP).
The BC 1.2 sink state machine is activated only when the power source connected does not support USB Power Delivery.
An overvoltage (OV) comparator in the USB PD block is used to detect cases where the power source is supplying incorrect voltage levels, and automatically shut down the power switches to protect the rest of the components on the board.
Refer Figure 4 to understand the PPS Sink demo application.
Figure 4. PPS Sink demo flowchart
The EZ-PD™ PMG1 MCU USB PD sink application functionality can be customized through a set of compile-time parameters that can be turned ON/OFF through the config.h header file.
| Macro name | Description | Allowed values |
|---|---|---|
CY_PD_SINK_ONLY |
Specifies that the application supports only the USB PD sink (consumer) role | Should be set to 1u |
CY_PD_PPS_SNK_ENABLE |
Enable for PPS Support | 1u or 0u |
NO_OF_TYPEC_PORTS |
Specifies the number of USB-C ports supported | Should be set to 1u |
CY_PD_REV3_ENABLE |
Enable USB PD Revision 3.0 support | 1u or 0u |
PD_PDO_SEL_ALGO |
Specifies the algorithm to be used while selecting the best source capability to power the board | 0u - Pick the source PDO delivering the maximum amount of power 1u - Pick the fixed source PDO delivering the maximum amount of power 2u - Pick the fixed source PDO delivering the maximum amount of current 3u - Pick the fixed source PDO delivering the maximum amount of voltage |
VBUS_FET_CTRL |
Selects the gate driver to be used to turn the consumer power path ON (applicable only for CY7110) | 0u - Gate driver which does not support internal pull-up 1u - Gate driver which supports pull-up for faster turn off |
BATTERY_CHARGING_ENABLE |
Enables BC 1.2 (CDP/DCP) detection when connected to a non-USB PD power source | 1u or 0u |
SNK_STANDBY_FET_SHUTDOWN_ENABLE |
Specifies whether the consumer power path should be disabled while PD contracts are being negotiated | 1u or 0u |
SYS_DEEPSLEEP_ENABLE |
Enables device entry into deep sleep mode for power saving when the CPU is idle | 1u or 0u |
The USB Type-C connection manager, USB Power Delivery (USB PD) protocol layer, and USB PD device policy engine state machine implementations are provided in the form of pre-compiled libraries as part of the PDStack middleWare library.
Multiple variants of the PDStack library with different feature sets are provided; you can choose the appropriate version based on the features required by the target application.
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PMG1_PD3_SNK_LITE: Library with support for USB Type-C sink operation and USB PD Revision 3.0 messaging. This library is chosen by default.
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PMG1_PD2_SNK_LITE: Library with support for USB Type-C sink operation and USB PD Revision 2.0 messaging. Using this library will reduce the flash (code) memory usage by the application.
The library of choice can be selected by editing the Makefile in the application folder and changing the value of the COMPONENTS variable. To use the PD Revision 2.0 library, replace the PMG1_PD3_SNK_LITE reference with PMG1_PD2_SNK_LITE.
The properties of the USB-C port including port role and the default response to various USB PD messages can be configured using the EZ-PD™ configurator utility.
These parameters have been set to the appropriate values for a Power Delivery sink application by default. To view or change the configuration, click on the EZ-PD™ Configurator item under BSP Configurators in the Quick Panel to launch the configurator.
Figure 5. USB Type-C port configuration using EZ-PD™ Configurator
Properties of the USB-C port are configured using the Port Information section. Because this application supports only the USB PD sink operation, the Port Role must be set as Sink and DRP Toggle must be disabled. Other parameters such as Manufacturer Vendor ID and Manufacturer Product ID can be set to desired values.
Figure 6. PPS sink PDO configuration using EZ-PD™ configurator
As this application supports Sink PPS. Sink PDO Type should be Programmable Power Supply and Sink PDO Enable must be enabled. Other parameters such as Maximum Voltage (mV), Minimum Voltage (mV), Operational Current (mA) and Min/Max Operating Current (mA) can be set to desired values depending on the PPS source used. A maximum of seven PDOs can be added using the configurator.
Figure 7. Extended sink capability configuration using EZ-PD™ configurator
The SKEDB section is used to input the extended sink capabilities response that will be sent by the application when queried by the power source. See the Power Delivery specification for details on the extended sink capabilities format.
Once the parameters have been updated as desired, save the configuration and build the application.
Table 1. Application resources
| Resource | Alias/object | Purpose |
|---|---|---|
| USB PD | PD_PORT0 | USB PD block used for PD communication |
| LED (BSP) | CYBSP_USER_LED | User LED to indicate connection state |
| Switch (BSP) | CYBSP_USER_SW | User Switch to send Get_PPS_Status PD message to PPS source |
| File | Purpose |
|---|---|
| src/app/app.c & .h | Defines data structures, function prototypes and implements functions to handle application-level USB Type-C and PD events |
| src/app/charger_detect.c & .h | Defines data structures, function prototypes and implements functions to handle BC 1.2 charger detection |
| src/app/fault_handlers.c | Implements functions to handle the various faults related to USB Type-C and PD |
| src/app/pdo.c & .h | Defines function prototypes and implements functions to evaluate source capabilities (Power Data Object) |
| src/app/psink.c & .h | Defines function prototypes and implements functions for power consumer path control |
| src/app/swap.c & .h | Defines function prototypes and implements functions to evaluate the USB PD role swap requests |
| src/app/vdm.c & .h | Defines data structures, function prototypes and implements functions to handle Vendor Defined Messages (VDM) |
| src/system/instrumentation.c & .h | Defines data structures, function prototypes and implements functions to monitor CPU resource usage |
| pps.c & .h | Defines function prototypes and implement functions related to PPS (Programmable Power Supply) |
| Resources | Links |
|---|---|
| Application notes | AN232553 - Getting started with EZ-PD™ PMG1 MCU on ModusToolbox™ AN232565 - EZ-PD™ PMG1 MCU hardware design guidelines and checklist |
| Code examples | Using ModusToolbox™ on GitHub |
| Device documentation | EZ-PD™ PMG1 MCU datasheets |
| Development kits | Select your kits from the Evaluation board finder page. |
| Libraries on GitHub | mtb-pdl-cat2 - Peripheral Driver Library (PDL) and docs |
| Middleware on GitHub | pdstack - PDStack Middleware Library and docs pdutils - PDUtils Middleware Library and docs |
| Tools | Eclipse IDE for ModusToolbox™ ModusToolbox™ is a collection of easy-to-use software and tools enabling rapid development with Infineon MCUs, covering applications from embedded sense and control to wireless and cloud-connected systems using AIROC™ Wi-Fi & Bluetooth® combo devices. |
Infineon provides a wealth of data at www.infineon.com to help you select the right device, and quickly and effectively integrate it into your design.
Document Title: CE238361 - EZ-PD™ PMG1 MCU: USB PD Sink PPS Demo
| Version | Description of change |
|---|---|
| 1.0.0 | New code example |
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