README.md

# EZ-PD™ PMG1 MCU: SCB UART transmit and receive with DMA

This code example demonstrates the UART transmit and receive operation on PMG1-S3 device using DMA. The application uses a serial terminal to read data and echoes what is received. The UART is configured to do both transmit and receive operations. <br>

[View this README on GitHub.](https://github.com/Infineon/mtb-example-pmg1-uart-transmit-receive-dma)

[Provide feedback on this code example.](https://cypress.co1.qualtrics.com/jfe/form/SV_1NTns53sK2yiljn?Q_EED=eyJVbmlxdWUgRG9jIElkIjoiQ0UyMzM3MTkiLCJTcGVjIE51bWJlciI6IjAwMi0zMzcxOSIsIkRvYyBUaXRsZSI6IkVaLVBEJnRyYWRlOyBQTUcxIE1DVTogU0NCIFVBUlQgdHJhbnNtaXQgYW5kIHJlY2VpdmUgd2l0aCBETUEiLCJyaWQiOiJwcnl4IiwiRG9jIHZlcnNpb24iOiIyLjAuMCIsIkRvYyBMYW5ndWFnZSI6IkVuZ2xpc2giLCJEb2MgRGl2aXNpb24iOiJNQ0QiLCJEb2MgQlUiOiJXSVJFRCIsIkRvYyBGYW1pbHkiOiJUWVBFLUMifQ==)

## Requirements

- [ModusToolbox&trade; software](https://www.infineon.com/modustoolbox) v3.0 or later (tested with v3.0)
- Board support package (BSP) minimum required version: 3.0.0
- Programming language: C
- Associated parts: [EZ-PD&trade; PMG1 S3](https://www.infineon.com/PMG1) parts

## Supported toolchains (make variable 'TOOLCHAIN')

- GNU Arm® Embedded Compiler v10.3.1 (`GCC_ARM`) - Default value of `TOOLCHAIN`
- Arm&reg; Compiler v6.13 (`ARM`)
- IAR C/C++ Compiler v8.42.2 (`IAR`)

## Supported kits (make variable 'TARGET')

- [EZ-PD&trade; PMG1-S3 prototyping kit](https://www.infineon.com/CY7113) (`PMG1-CY7113`) - Default value of `TARGET`

## Hardware setup

For kit version older than **CY7113 board revision 3 or lower**, connect J6.10 to J3.8 and J6.9 to J3.10 to establish a UART connection between KitProg3 and the PMG1 device. See the kit user guide to ensure that the board is configured correctly. Prototyping kits with a higher revision have UART lines internally connected. Therefore, external wiring is not required. <br>

**Note:** If UART DEBUG PRINT messages are enabled, UART connection are needed. Please view compile-time configuration for more information.

## Software setup

Install a terminal emulator if you don't have one. Instructions in this document use [Tera Term](https://ttssh2.osdn.jp/index.html.en).

This example requires no additional software or tools.

## Using the code example

Create the project and open it using one of the following:

<details><summary><b>In Eclipse IDE for ModusToolbox&trade; software</b></summary>

1. Click the **New Application** link in the **Quick Panel** (or, use **File** > **New** > **ModusToolbox&trade; Application**). This launches the [Project Creator](https://www.infineon.com/ModusToolboxProjectCreator) tool.

2. Pick a kit supported by the code example from the list shown in the **Project Creator - Choose Board Support Package (BSP)** dialog.

   When you select a supported kit, the example is reconfigured automatically to work with the kit. To work with a different supported kit later, use the [Library Manager](https://www.infineon.com/ModusToolboxLibraryManager) to choose the BSP for the supported kit. You can use the Library Manager to select or update the BSP and firmware libraries used in this application. To access the Library Manager, click the link from the **Quick Panel**.

   You can also just start the application creation process again and select a different kit.

   If you want to use the application 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.

3. In the **Project Creator - Select Application** dialog, choose the example by enabling the checkbox.

4. (Optional) Change the suggested **New Application Name**.

5. The **Application(s) Root Path** defaults to the Eclipse workspace which is usually the desired location for the application. If you want to store the application in a different location, you can change the *Application(s) Root Path* value. Applications that share libraries should be in the same root path.

6. Click **Create** to complete the application creation process.

For more details, see the [Eclipse IDE for ModusToolbox&trade; software user guide](https://www.infineon.com/MTBEclipseIDEUserGuide) (locally available at *{ModusToolbox&trade; software install directory}/docs_{version}/mt_ide_user_guide.pdf*).

</details>

<details><summary><b>In command-line interface (CLI)</b></summary>

ModusToolbox&trade; software provides the Project Creator as both a GUI tool and the command line tool, "project-creator-cli". The 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&trade; software 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&trade; software installation instead of a standard Windows command-line application. This shell provides access to all ModusToolbox&trade; software 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 "project-creator-cli" tool has the following arguments:

Argument | Description | Required/optional
---------|-------------|-----------
`--board-id` | Defined in the `<id>` field of the [BSP](https://github.com/Infineon?q=bsp-manifest&type=&language=&sort=) manifest | Required
`--app-id`   | Defined in the `<id>` field of the [CE](https://github.com/Infineon?q=ce-manifest&type=&language=&sort=) 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

<br>

The following example clones the "[SCB UART transmit and receive with DMA](https://github.com/Infineon/mtb-example-pmg1-uart-transmit-receive-dma)" application with the desired name "MyScbUartDma" configured for the *PMG1-CY7113* BSP into the specified working directory, *C:/mtb_projects*:

   ```
   project-creator-cli --board-id PMG1-CY7113 --app-id mtb-example-pmg1-uart-transmit-receive-dma --user-app-name MyScbUartDma --target-dir "C:/mtb_projects"
   ```

**Note:** The project-creator-cli tool uses the `git clone` and `make getlibs` commands to fetch the repository and import the required libraries. For details, see the "Project creator tools" section of the [ModusToolbox&trade; software user guide](https://www.infineon.com/ModusToolboxUserGuide) (locally available at *{ModusToolbox&trade; software install directory}/docs_{version}/mtb_user_guide.pdf*).

To work with a different supported kit later, use the [Library Manager](https://www.infineon.com/ModusToolboxLibraryManager) to choose the BSP for the supported kit. You can invoke the Library Manager GUI tool from the terminal using `make library-manager` command or use the Library Manager CLI tool "library-manager-cli" to change the BSP.

The "library-manager-cli" tool has the following arguments:

Argument | Description | Required/optional
---------|-------------|-----------
`--add-bsp-name` | Name of the BSP that should be added to the application | Required
`--set-active-bsp` | Name of the BSP that should be as active BSP for the application | Required
`--add-bsp-version`| Specify the version of the BSP that should be added to the application if you do not wish to use the latest from manifest | Optional
`--add-bsp-location`| Specify the location of the BSP (local/shared) if you prefer to add the BSP in a shared path | Optional

<br>

The following example adds the PMG1-CY7113 BSP to the already created application and makes it the active BSP for the app:

   ```
   ~/ModusToolbox/tools_3.0/library-manager/library-manager-cli --project "C:/mtb_projects/MyMyScbUartDma" --add-bsp-name PMG1-CY7113--add-bsp-version "latest-v3.X" --add-bsp-location "local"

   ~/ModusToolbox/tools_3.0/library-manager/library-manager-cli --project "C:/mtb_projects/MyMyScbUartDma" --set-active-bsp APP_PMG1-CY7113

   ```

</details>

<details><summary><b>In third-party IDEs</b></summary>

Use one of the following options:

- **Use the standalone [Project Creator](https://www.infineon.com/ModusToolboxProjectCreator) tool:**

   1. Launch Project Creator from the Windows Start menu or from *{ModusToolbox&trade; software install directory}/tools_{version}/project-creator/project-creator.exe*.

   2. In the initial **Choose Board Support Package** screen, select the BSP, and click **Next**.

   3. In the **Select Application** screen, select the appropriate IDE from the **Target IDE** drop-down menu.

   4. Click **Create** and follow the instructions printed in the bottom pane to import or open the exported project in the respective IDE.

<br>

- **Use command-line interface (CLI):**

   1. Follow the instructions from the **In command-line interface (CLI)** section to create the application.

   2. Export the application to a supported IDE using the `make <ide>` command.

   3. Follow the instructions displayed in the terminal to create or import the application as an IDE project.

For a list of supported IDEs and more details, see the "Exporting to IDEs" section of the [ModusToolbox&trade; software user guide](https://www.infineon.com/ModusToolboxUserGuide) (locally available at *{ModusToolbox&trade; software install directory}/docs_{version}/mtb_user_guide.pdf*).

</details>


## Operation

1. Ensure that the steps listed in the [Hardware setup](#hardware-setup) section are completed.

2. Ensure that the jumper shunt on the power selection jumper (J5) is placed at position 2-3 to enable programming.

3. Connect the board to your PC using the USB cable through the KitProg3 USB connector. This cable is used for programming the PMG1 device and as a USB-UART bridge to the PC during operation.

4. Program the board using one of the following:

   <details><summary><b>Using Eclipse IDE for ModusToolbox&trade; software</b></summary>

      1. Select the application project in the Project Explorer.

      2. In the **Quick Panel**, scroll down, and click **\<Application Name> Program (KitProg3_MiniProg4)**.
   </details>

   <details><summary><b>Using CLI</b></summary>

     From the terminal, execute the `make program` command 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
      ```
   </details>

5. After programming the kit, disconnect the USB cable and change the position on the power selection jumper (J5) to 1-2 to power the kit through the USBPD port.

6. Connect the USB cable back to the KitProg3 USB connector.

7. Open a terminal program and select the KitProg3 COM port. Set the serial port parameters to 8N1 and 115200 baud.

8. Connect the USBPD port to a USB-C power adapter or your PC using a USB Type-C cable to power the kit.

9. The application starts automatically. Confirm that "\<CE Title>"  is displayed on the UART terminal.

10. Start typing to see the echo on the terminal:

   **Figure 1. Sample output**

<img src = "images/sample_output.png" width = "600"/>
<br>

## Debugging

You can debug the example to step through the code. In the 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 cable through the KitProg3 USB connector and the jumper shunt on the power selection jumper (J5) is placed at position 1-2.

See the "Debug mode" section in the kit user guide for debugging the application on the CY7110 prototyping kit. For more details, see the "Program and debug" section in the [Eclipse IDE for ModusToolbox&trade; software user guide](https://www.infineon.com/MTBEclipseIDEUserGuide).

## Design and implementation

Figure 2 shows the firmware flowchart for the design.

**Figure 2. Firmware flowchart**

<img src = "images/firmware_flowchart.png" width = "600"/>
<br>

SCB4 is initialized as UART to receive and send data to a terminal emulator. To implement the UART data transfer on the SCB hardware block, the UART Peripheral Driver Library (PDL) APIs are used. The UART is initialized with the following settings:

- Baud rate: 115200
- Data width: 8 bits
- Parity: None
- Stop bit: 1
- The clock input of the block is connected to a 48-MHz PERI-derived clock

**Figure 3. UART configuration**

<img src = "images/uart_configuration_1.png" width = "800"/>
<br>

**Figure 4. UART configuration (continued)**

<img src = "images/uart_configuration_2.png" width = "800"/>
<br>

The application uses DMA to handle the data received in the UART Rx FIFO. Two DMA channels (DMAC Channel 0 and DMAC Channel 1) are used to handle the data in receive and transmit directions respectively. Two SRAM buffers are alternately used on the receive side to hold the data received from the UART terminal. These buffers are called "ping-pong buffers" and are mainly used to provide the time for pulling the data out of either buffer.

Each DMA Channel has one or more channel descriptor structures which are normally located in the RAM. These descriptors include source and destination addresses for the channel as well as the information on the data count, data transfer width, trigger type, etc. For more information on DMAC block configuration and usage, see [mtb-pdl-cat2 DMAC](https://infineon.github.io/mtb-pdl-cat2/pdl_api_reference_manual/html/group__group__dmac.html) documentation.

PMG1-S3 has 16 DMA channels. To configure or enable these DMA channels, click **Device Configurator 3.0** under **Tools** in the Quick Panel and click on DMA tab as shown in the following figure:

**Figure 5. DMA configuration**

<img src = "images/dma_configuration.png" width = "900"/>
<br>

The RxDma (DMAC Channel 0) resource handles the data transfer in the receive direction. RxDma has two descriptors in the chain; these are configured such that the source alternates between the ping-pong buffers in the receive direction. RxDma channel and 2 descriptors (ping-pong) are configured as follows:

**Figure 6. RxDma channel configuration**

<img src = "images/rxdma_parameters.png" width = "800"/>
<br>

The TxDma (DMAC Channel 1) resource is used to handle the data in the transmit direction. TxDma has only one descriptor; the source address for this channel is alternated between ping-pong buffers upon reception of each byte of data to transmit back the correct value. TxDma channel is configured as follows:

**Figure 7. TxDma channel configuration**

<img src = "images/txdma_parameters.png" width = "800"/>
<br>

The data received from the serial terminal is echoed back to the serial terminal.

**Figure 8. Buffering**

<img src = "images/buffering.png" width = "600"/>
<br>

### Compile-time configurations
The EZ-PD&trade; PMG1 MCU SCB UART transmit and receive with DMA application functionality can be customized through the compile-time parameter that can be turned ON/OFF through the *main.c* file.
 Macro name          | Description                           | Allowed values 
 :------------------ | :------------------------------------ | :------------- 
 `DEBUG_PRINT`     | Debug print macro to enable UART print | 1u to enable <br> 0u to disable |

### Resources and settings

**Table 1. Application resources**

| Resource  | Alias/object   | Purpose                              |
| :-------- | :------------- | :----------------------------------- |
| SCB(UART)(PDL)| KIT_UART     | UART object used for Debug UART port |
| DMA (PDL) | RxDma | Data transfer         |
| DMA (PDL) | TxDma | Data transfer         |

### List of application files and their usage

| File  | Purpose                              |
| :-------- | :----------------------------------- |
| source/UartDma.h | Defines function prototypes and macros to configure DMA channels and handle transfers |
| source/UartDma.c | Implements functions to configure DMA channels and handle transfers |

## Related resources

Resources | Links
-----------|------------------
Application notes |[AN232553](https://www.infineon.com/AN232553) – Getting started with EZ-PD&trade; PMG1 MCU on ModusToolbox&trade; software <br> [AN232565](https://www.infineon.com/an232565) – EZ-PD&trade; PMG1 hardware design guidelines and checklist
Code examples  | [Using ModusToolbox&trade; software](https://github.com/Infineon/Code-Examples-for-ModusToolbox-Software) on GitHub
Device documentation | [EZ-PD&trade; PMG1 MCU datasheets](https://www.infineon.com/PMG1DS)
Development kits | Select your kits from the [Evaluation Board Finder](https://www.infineon.com/cms/en/design-support/finder-selection-tools/product-finder/evaluation-board) page.
Libraries on GitHub | [mtb-pdl-cat2](https://github.com/Infineon/mtb-pdl-cat2) – Peripheral driver library (PDL) and docs
Tools | [Eclipse IDE for ModusToolbox&trade; software](https://www.infineon.com/modustoolbox) <br> ModusToolbox&trade; software 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.

## Other resources

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 history

Document Title: *CE233719* – *EZ-PD&trade; PMG1 MCU: SCB UART transmit and receive with DMA*

| Version | Description of change |
| ------- | --------------------- |
| 1.0.0   | New code example      |
| 2.0.0   | Major update to support ModusToolbox&trade; v3.0. This version is not backward compatible with previous versions of ModusToolbox&trade; |
------

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