EZ-USB™ FX2G3: LVCMOS slave FIFO IN OUT application

This code example explains the configuration and usage of Sensor Interface Port (SIP) on the EZ-USB™ FX2G3 device to implement the Bi-directional Synchronous Slave FIFO protocol.

A master device (like the FPGA add-on board) that implements the Infineon-defined Synchronous Slave FIFO protocol is required to perform data transfers with this application.

View this README on GitHub.

Provide feedback on this code example.

Requirements

ModusToolbox™ v3.5 or later (tested with v3.5)
Board support package (BSP) minimum required version: 4.3.3
Programming language: C
Associated parts: EZ-USB™ FX2G3

Supported toolchains (make variable 'TOOLCHAIN')

GNU Arm® Embedded Compiler v14.2.1 (GCC_ARM) – Default value of TOOLCHAIN
Arm® Compiler v6.22 (ARM)

Supported kits (make variable 'TARGET')

EZ-USB™ FX2G3 DVK (KIT_FX2G3_104LGA) – Default value of TARGET

Hardware setup

This example uses the board's default configuration with the inclusion of the FPGA add-on board. See the kit user guide to ensure that the board is configured correctly.

Software setup

See the ModusToolbox™ tools package installation guide for information about installing and configuring the tools package.

Install a terminal emulator if you don't have one. Instructions in this document use Tera Term.

Install the EZ-USB™ FX Control Center application from Infineon Developer Center.

Optional software

EZ-USB™ GPIF III Designer - EZ-USB™ GPIF III Designer, a desktop application that guides the process of defining general programmable interface and state machine to generate C source header for FX device family.

Using the code example

Create the project

The ModusToolbox™ tools package provides the Project Creator as both a GUI tool and a command line tool.

Use Project Creator GUI

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)
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 "EZ-USB™ FX2G3: LVCMOS Slave FIFO IN OUT application" application with the desired name "FX2G3_Slave_FIFO_IN_OUT" configured for the KIT_FX2G3_104LGA BSP into the specified working directory, C:/mtb_projects:

project-creator-cli --board-id KIT_FX2G3_104LGA --app-id mtb-example-fx2g3-slave-fifo-in-out --user-app-name FX2G3_Slave_FIFO_IN_OUT --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 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™ tools package user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mtb_user_guide.pdf).

Open the project

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).

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).

Using this code example with specific products

By default, the code example builds for the CYUSB2318-BF104AXI product.

List of supported products

CYUSB2318-BF104AXI
CYUSB2317-BF104AXI

Setup for a different product

Perform the following steps to build this code example for a different, supported product:

Launch the BSP assistant tool:

a. Eclipse IDE: Launch the BSP Assistant tool by navigating to Quick Panel > Tools

b. Visual Studio Code: Select the ModusToolbox™ extension from the menu bar, and launch the BSP Assistant tool, available in the Application menu of the MODUSTOOLBOX TOOLS section from the left pane
In BSP Assistant, select Devices from the tree view on the left
Choose CYUSB231x-BF104AXI from the drop-down menu, on the right
Click Save

This closes the BSP Assistant tool.
Navigate the project with the IDE's Explorer and delete the GeneratedSource folder (if available) at <bsp-root-folder>/bsps/TARGET_APP_KIT_FX2G3_104LGA/config

Note: For products CYUSB2315-BF104AXI and CYUSB2316-BF104AXI, additionally delete the *.cyqspi file from the config/ directory.
Launch the Device Configurator tool

a. Eclipse IDE: Select your project in the project explorer, and launch the Device Configurator tool by navigating to Quick Panel > Tools

b. Visual Studio Code: Select the ModusToolbox™ extension from the left menu bar, and launch the Device Configurator tool, available in the BSP menu of the MODUSTOOLBOX TOOLS section from the left pane
Correct the issues (if any) specified in the Errors section on the bottom

a. For a switch from the CYUSB2318-BF104AXI product to any other, a new upper limit of 100 MHz is imposed on the desired frequency that can originate from the PLL. Select this issue and change the desired frequency from 150 MHz to 75 MHz

b. The CLK_PERI clock, which is derived from this new source frequency, is also affected. To restore it to its original frequency, go to the System Clocks tab, select CLK_PERI, and set its divider to '1' (instead of '2')

Note: For the CYUSB2315-BF104AXI product, to enable UART logging through SCB, follow the steps below:
a. Set the USBFS_LOGS_ENABLE macro to 0 in the Makefile
b. In main.c, modify the SCB configuration by changing LOGGING_SCB from (SCB4) to (SCB0), LOGGING_SCB_IDX from (4) to (0) and the value of dbgCfg.dbgIntfce from CY_DEBUG_INTFCE_UART_SCB4 to CY_DEBUG_INTFCE_UART_SCB0
c. Launch the Device Configurator tool to disable SCB4, and enable SCB0 for UART. Set 921600 baud, 9 Oversample, and use the 16 bit Divider 0 clk clock

Compile-time configurations

This application's functionality can be customized by setting variables in Makefile or by configuring them through make CLI arguments.

Run the make build command or build the project in your IDE to compile the application and generate a USB bootloader-compatible binary. This binary can be programmed onto the EZ-USB™ FX2G3 device using the EZ-USB™ FX Control Center application
Run the make build CORE=CM0P command or set the variable in Makefile to compile and generate the binary for the Cortex® M0+ core. By default, CORE is set as CM4 and the binary is compiled and generated for the Cortex® M4 core
Choose between the Arm® Compiler or the GNU Arm® Embedded Compiler build toolchains by setting the TOOLCHAIN variable in Makefile to ARM or GCC_ARM respectively. If you set it to ARM, ensure to set CY_ARM_COMPILER_DIR as a make variable or environment variable, pointing to the path of the compiler's root directory

By default, the application is configured to receive data from a 16-bit wide LVCMOS interface in SDR mode and make a USBHS data connection. Additional settings can be configured through macros specified by the DEFINES variable in Makefile:

Table 1. Macro description

Macro name	Description	Allowed values
BUS_WIDTH_16	Select the LVCMOS bus width	1u for 16-bit 0u for 8-bit bus width
USBFS_LOGS_ENABLE	Enable debug logs through the USBFS port	1u for debug logs over USBFS 0u for debug logs over UART (SCB4)
CLKOUT_ENABLE	Enabled CLKOUT	1u to enable CLKOUT fetaure 0u to disable

Operation

Note: This code example currently supports Windows hosts. Support for Linux and macOS will be added in upcoming releases.

Connect the board (J2) to your PC using the provided USB cable
Connect the USBFS port (J7) on the board to PC for debug logs
Open a terminal program and select the Serial COM port. Set the serial port parameters to 8N1 and 921600 baud
Perform the following steps to program the board using the EZ-USB™ FX Control Center application
1. Perform the following steps to enter into the Bootloader mode:
  
  a. Press and hold the PMODE (SW1) switch
  b. Press and release the RESET switch
  c. Release the PMODE switch
2. Open EZ-USB™ FX Control Center application
  The EZ-USB™ FX2G3 device displays as EZ-USB™ FX Bootloader
3. Navigate to Program > Internal Flash
4. Navigate to the /build/APP_KIT_FX2G3_104LGA/Release/ folder within the CE directory and locate the .hex file, and program
5. Select the EZ-USB™ FX Bootloader device in EZ-USB™ FX Control Center
6. Navigate to Program > External Flash
7. Browse the FPGA binary file in <CE Title>/BitFile folder
8. Once the FPGA binary programming is successful, return to the USB Bootloader mode
  Once the firmware binary has been programmed onto the FX2G3 device flash, the bootloader will keep transferring control to the application on every subsequent reset
9. To return the control to USB bootloader, press BOOT MODE/PMODE (SW1) to switch on KIT_FX2G3_104LGA DVK
  While the device is reset or power cycled, the device will stay in the Bootloader mode instead of booting into the application
10. Select the FX Bootloader device in EZ-USB™ FX Control Center and navigate to Program > Internal Flash
11. Navigate to the /build/APP_KIT_FX2G3_104LGA/Release/ folder within the CE directory and locate the .hex file, and program
  Confirm if the programming is successful in the log window of the EZ-USB™ FX Control Center application
After programming, the application starts automatically. Confirm that the title is displayed on the UART terminal as follows:

Figure 1. Terminal output on program startup

The device will enumerate as a WinUSB device.
When the WinUSB device appears, open EZ-USB™ FX Control Center, navigate to the Performance Measurement tab and initiate BULK IN Data transfers on the selected endpoint

Debugging

Using the Arm® debug port

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. For details, see the "Program and debug" section in the Eclipse IDE for ModusToolbox™ user guide.

Note: (Only while debugging) On the CM4 CPU, some code in main() may execute before the debugger halts at the beginning of main(). This means that some code executes twice – once before the debugger stops execution, and again after the debugger resets the program counter to the beginning of main(). See KBA231071 to learn about this and for the workaround.

In other IDEs

Follow the instructions in your preferred IDE.

Log messages

By default, the USBFS port is enabled for debug logs.

To enable debug logs on UART, set USBFS_LOGS_ENABLE compiler flag to '0u' in Makefile. SCB4 of the EZ-USB™ FX2G3 device is used as UART with a baud rate of 921,600 to send out log messages through the P11.0 pin.

The verbosity of the debug log output can be modified by setting the DEBUG_LEVEL macro in main.c file with the following values for debugging:

Table 2. Debug values

Macro value	Description
1u	Enable only error messages
2u	Enable error and warning messages
3u	Enable info messages as well
4u	Enable all message types

Design and implementation

This code example demonstrates the implementation of a Synchronous Slave FIFO interface, where the Sensor Interface Port (SIP) on the EZ-USB™ FX2G3 device is connected to an FPGA/Master, read and write access to the internal FIFO buffers of the EZ-USB™ FX2G3 device. This application uses various low-performance peripherals to interface with the system such as:

I2C master to configure the data source/FPGA/master
SMIF (in x4 or Quad mode) interface for downloading the FPGA configuration binary on every bootup
Enable debug prints over CDC using USBFS block on EZ-USB™ FX2G3 device

Features of the application

USB specifications: USB 2.0 (both Hi-Speed and Full-Speed)
Supports write/read operations initiated by the FPGA/master device
Supports FPGA writes on the GPIF thread '1' and FPGA reads on GPIF thread '0'
Supports 48 MHz clock on CLKOUT pin of EZ-USB™ FX2G3

Note: By default, CLKOUT fetaure is disabled. CLKOUT_ENABLE should be set to 1u in Makefile to enable this feature

Data streaming path

The device enumerates as a vendor-specific USB device with two bulk endpoints (1-IN and 2-OUT)
The application supports the two bulk endpoints with a maximum packet size of 512 bytes each
The application supports data transfers in a data loopback manner where the FX2G3 loops the data over LVCMOS through FPGA. The data transfer path is as follows:
- FX2G3 receives data from USB Host over EP 2-OUT endpoint
- FX2G3 configures FPGA in RX mode (using I2C writes) and FPGA reads data from GPIF Thread-0 of LVCMOS
- FX2G3 sets FPGA in TX mode (using I2C writes) and receives the looped data from FPGA on GPIF thread-1
- FX2G3 sends the received data on EP 1-IN endpoint to USB host
The device loops the data through the following data paths:
- TX Data Path: Data is received on EP 2-OUT is sent to LVCMOS socket 1 (mapped to GPIF thread 1)
- RX Data Path: Data is received on LVCMOS Socket 0 (mapped to GPIF thread 0) and sent on EP 1-IN
Eight DMA buffers of 61440 (60KB) bytes size are used to hold in Stream IN and OUT transfers, 4 in each direction

Application workflow

The application flow involves three main steps:

Initialization
USB device enumeration
Slave FIFO IN transfer

Initialization

During initialization, the following steps are performed:

All the required data structures are initialized
USBD and USB driver (CAL) layers are initialized
Application registers all descriptors supported by function/application with the USBD layer
Application registers callback functions for different events like RESET, SUSPEND, RESUME, SET_CONFIGURATION, SET_INTERFACE, SET_FEATURE, and CLEAR_FEATURE. USBD will call the respective callback function when the corresponding events are detected
Initialize the data transfer state machines
Application registers handlers for all relevant interrupts
Application makes the USB device visible to the host by calling the Connect API
FPGA is configured using the SMIF (in x4 or quad mode) block to read the bit file stored in the external flash. FPGA sees the data on bus and gets configured
FPGA is initialized using I2C writes to FPGA registers
Application initializes the SIP block on EZ-USB™ FX2G3 as required by the selected LVCMOS operating mode

USB device enumeration

During USB device enumeration, the host requests for descriptors that are already registered with the USBD layer during the initialization phase
The host sends the SET_CONFIGURATION and SET_INTERFACE commands to activate the required function in the device
After the SET_CONFIGURATION and SET_INTERFACE commands, the application task takes control and enables the endpoints for data transfer

Slave FIFO IN OUT transfer

Depending on the compile-time options, data loopback or stream in/out modes are selected
Once the data transfers are initiated from the host application, FPGA/Master is configured to the stream data
The DMA ready flag on the SIP interface is asserted
Based on the FPGA configuration and mode selected, FPGA starts reading/writing from/to the EZ-USB™ FX2G3 device
DataWire DMA channels are used in the case of USBHS transfers
Data moves from/to USB device Bulk endpoint-IN to/from the host application

Slave FIFO interface

The Synchronous Slave FIFO interface connections are as follows:

Table 3. Control signal usage in LVCMOS Slave FIFO state machine

FX2G3 pin	Function	Description
P0CTL0	SLCS#	Active LOW Chip Select signal. Should be asserted (LOW) by the master/FPGA when communicating with FX2G3
P0CTL1	SLWR#	Active LOW Write Enable signal. Should be asserted (LOW) by the master/FPGA when sending any data to the FX2G3
P0CTL2	SLOE#	Active LOW Output Enable signal
P0CTL3	SLRD#	Active LOW Read Enable signal. Not used in this application as data is only being received by FX2G3
P0CTL4	PKTEND#	Active LOW Packet End signal. Should be asserted (LOW) when the FPGA/master wants to terminate the ongoing DMA transfer
P0CTL5	FlagA	Active LOW DMA ready indication for currently addressed/active thread
P0D8	A0	LS bit of 2-bit address bus used to select thread (applicable for 8-bit LVCMOS bus width)
P0D9	A1	MS bit of 2-bit address bus used to select thread (applicable for 8-bit LVCMOS bus width)
P0CTL9	A0	LS bit of 2-bit address bus used to select thread (applicable for 16-bit LVCMOS bus width)
P0CTL8	A1	MS bit of 2-bit address bus used to select thread (applicable for 16-bit LVCMOS bus width)

Figure 2. Control signal usage in LVCMOS receiver state machine

FPGA BitFile information

The FPGA binary in BitFile folder of the project can be programmed to an external flash on the EZ-USB™ FX2G3 DVK using the mtb-example-fx2g3-flash-loader firmware.

Perform the following steps to program the binary file to the external flash:

Program mtb-example-fx2g3-flash-loader.hex using EZ-USB™ FX Control Center
Navigate to Program > External Flash and browse the FPGA binary file
Check the programming status

Table 4. BitFile description

BitFile	Description
FX2G3_Design_PassiveX4_16Bit_LVCMOS_TX_RX.bin	LVCMOS RX 16-bit for the FPGA add-on board

FPGA configuration

FPGA configuration is done using the SMIF Block of EZ-USB™ FX2G3. SMIF (in x4 or Quad mode) interface is used for downloading the FPGA configuration binary on every bootup. Steps to configure FPGA (in Passive serialx4 mode)

EZ-USB™ FX2G3 deasserts INT_RESET pin
EZ-USB™ FX2G3 starts sending dummy SMIF (in x4 or Quad mode) clock to read the FPGA BitFile from SPI flash
EZ-USB™ FPGA listens to the data on the SMIF lines and configures itself
EZ-USB™ FPGA asserts CDONE# when configuration is complete

Table 5. GPIOs for configuring FPGA on KIT_FX2G3_104LGA DVK

FX2G3 Pin	Function	Description
GPIO5	CDONE#	Active HIGH signal. FPGA asserts when FPGA configuration is completed
GPIO6	INT_RESET#	Active LOW signal. FX device asserts to reset the FPGA
GPIO10	SSN#	FPGA configuration type selection

Application files

Table 6. Application file description

File	Description
gpif_header.h	Generated Header file for GPIF state configuration for LVCMOS interface
usb_app.c	C source file implementing slave FIFO IN OUT application logic
usb_app.h	Header file for application data structures and functions declaration
usb_descriptors.c	C source file containing the USB descriptors
main.c	Source file for device initialization, ISRs, LVCMOS interface initialization, etc
usb_i2c.c	C source file with I2C handlers
usb_i2c.h	Header file with I2C application constants and the function definitions
usb_qspi.c	C source file with SMIF handlers and FPGA configuration functions
usb_qspi.h	Header file with SMIF application constants and the function definitions
cm0_code.c	CM0 initialization code
Makefile	GNU make compliant build script for compiling this example

Related resources

Resources	Links
User guide	EZ-USB™ FX2G3 SDK user guide
Code examples	Using ModusToolbox™ on GitHub
Device documentation	EZ-USB™ FX2G3 datasheets
Development kits	Select your kits from the Evaluation board finder
Libraries on GitHub	mtb-pdl-cat1 – Peripheral Driver Library (PDL) and documents
Middleware on GitHub	usbfxstack – USBFXStack middleware library and documents
Tools	ModusToolbox™ – ModusToolbox™ software is a collection of easy-to-use libraries and tools enabling rapid development with Infineon MCUs for applications ranging from wireless and cloud-connected systems, edge AI/ML, embedded sense and control, to wired USB connectivity using PSOC™ Industrial/IoT MCUs, AIROC™ Wi-Fi and Bluetooth® connectivity devices, XMC™ Industrial MCUs, and EZ-USB™/EZ-PD™ wired connectivity controllers. ModusToolbox™ incorporates a comprehensive set of BSPs, HAL, libraries, configuration tools, and provides support for industry-standard IDEs to fast-track your embedded application development

Compatibility information:

This code example uses the PDL layer for direct communication with device peripherals, without relying on HAL peripheral APIs
This code example relies on the USBFXStack middleware library for USBFS and does not support USBFS through the USB Device Middleware Library

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: CE241974 – EZ-USB™ FX2G3: LVCMOS Slave FIFO IN OUT application

Version	Description of change
1.0.0	New code example

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License

Infineon/mtb-example-fx2g3-slave-fifo-in-out

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