Create a compact bridge to I2C devices with FT201X and STM32F407VGT6
Full speed USB to I2C bridge
Published Dec 29, 2023
Click board™
USB to I2C 2 Click
Dev Board
Clicker 4 for STM32F4
Compiler
NECTO Studio
MCU
STM32F407VGT6
Discover the power of full-speed USB to I2C bridge and elevate your solution to new heights
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Hardware Overview
How does it work?
USB to I2C 2 Click is based on the FT201X, a USB to I2C interface device which simplifies USB implementations from FTDI. The FT201X is USB 2.0 full-speed compatible and handles the entire USB protocol by itself; no USB-specific firmware programming is required. It fully integrates 2048-byte Multi-Time-Programmable (MTP) memory for storing device descriptors, CBUS I/O user-desirable configuration, clock generation with no external crystal required, and optional clock output selection enabling a glue-less interface to external MCU or FPGA. This Click board™ communicates with MCU using the standard I2C 2-Wire interface to read data and configure settings, supporting Standard Mode operation with a clock frequency of 100kHz and Fast Mode up to 400kHz.
Since the FT201X for proper operation requires a 5V only, this Click board™ also features the PCA9306 voltage-level translator from Texas Instruments. The I2C interface bus lines are routed to the dual bidirectional voltage-level translator, allowing this Click board™ to work properly with both 3.3V and 5V MCUs. The FT201X also contains an embedded fully integrated MTP memory used to specify the functionality of the Control Bus (CBUS) pins, the current drive on each signal pin, the current limit for the USB bus, and the descriptors of the device. There are six configurable CBUS I/O pins, two routed on default AN and INT pins of the mikroBUS™ socket, marked as CB0 and CB1, alongside the two blue LED indicators labeled as CBUS0 and CBUS1 used for optional user-configurable
visual indication. The other four CBUS pins can be found on the onboard CBUS header and be used as user-configurable CBUS signals. A wide range and the way of using these pins can be found in the attached datasheet. This board also uses an active-low reset signal routed on the RST pin of the mikroBUS™ socket, which provides a reliable Power-On reset to the device's internal circuitry at Power-Up. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. However, the Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used, as a reference, for further development.
Features overview
Development board
Clicker 4 for STM32F4 is a compact development board designed as a complete solution that you can use to quickly build your own gadgets with unique functionalities. Featuring an STM32F407VGT6 MCU, four mikroBUS™ sockets for Click boards™ connectivity, power management, and more, it represents a perfect solution for the rapid development of many different types of applications. At its core is an STM32F407VGT6 MCU, a powerful microcontroller by STMicroelectronics based on the high-performance
Arm® Cortex®-M4 32-bit processor core operating at up to 168 MHz frequency. It provides sufficient processing power for the most demanding tasks, allowing Clicker 4 to adapt to any specific application requirements. Besides two 1x20 pin headers, four improved mikroBUS™ sockets represent the most distinctive connectivity feature, allowing access to a huge base of Click boards™, growing on a daily basis. Each section of Clicker 4 is clearly marked, offering an intuitive and clean interface. This makes working with the
development board much simpler and, thus, faster. The usability of Clicker 4 doesn’t end with its ability to accelerate the prototyping and application development stages: it is designed as a complete solution that can be implemented directly into any project, with no additional hardware modifications required. Four mounting holes [4.2mm/0.165”] at all four corners allow simple installation by using mounting screws.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M4
MCU Memory (KB)
10
Silicon Vendor
STMicroelectronics
Pin count
100
RAM (Bytes)
100
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Clicker 4 for STM32F4 as your development board.
Track your results in real time
Application Output via Debug Mode
1. Once the code example is loaded, pressing the "DEBUG" button initiates the build process, programs it on the created setup, and enters Debug mode.
2. After the programming is completed, a header with buttons for various actions within the IDE becomes visible. Clicking the green "PLAY" button starts reading the results achieved with the Click board™. The achieved results are displayed in the Application Output tab.
Software Support
Library Description
This library contains API for USB to I2C 2 Click driver.
Key functions:
usbtoi2c2_write_dataThis function writes a desired number of data bytes by using I2C serial interface.usbtoi2c2_read_dataThis function reads a desired number of data bytes by using I2C serial interface.usbtoi2c2_reset_deviceThis function resets the device by toggling the RST pin state.
Open Source
Code example
The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.
/*!
* @file main.c
* @brief USBtoI2C2 Click example
*
* # Description
* This example demonstrates the use of USB to I2C 2 click by echoing back all
* the received messages.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and performs the click default configuration.
*
* ## Application Task
* Any data which the host PC sends to the Virtual COM Port (for example, typed into the terminal
* window in UART Terminal) will be sent over USB to the click board and then it will be read and
* echoed back by the MCU to the PC where the terminal program will display it.
*
* @note
* Make sure to download and install appropriate VCP drivers on the host PC.
*
* @author Stefan Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "usbtoi2c2.h"
static usbtoi2c2_t usbtoi2c2;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
usbtoi2c2_cfg_t usbtoi2c2_cfg; /**< Click config object. */
/**
* Logger initialization.
* Default baud rate: 115200
* Default log level: LOG_LEVEL_DEBUG
* @note If USB_UART_RX and USB_UART_TX
* are defined as HAL_PIN_NC, you will
* need to define them manually for log to work.
* See @b LOG_MAP_USB_UART macro definition for detailed explanation.
*/
LOG_MAP_USB_UART( log_cfg );
log_init( &logger, &log_cfg );
log_info( &logger, " Application Init " );
// Click initialization.
usbtoi2c2_cfg_setup( &usbtoi2c2_cfg );
USBTOI2C2_MAP_MIKROBUS( usbtoi2c2_cfg, MIKROBUS_1 );
if ( I2C_MASTER_ERROR == usbtoi2c2_init( &usbtoi2c2, &usbtoi2c2_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
if ( USBTOI2C2_ERROR == usbtoi2c2_default_cfg ( &usbtoi2c2 ) )
{
log_error( &logger, " Default configuration." );
for ( ; ; );
}
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
uint8_t rx_data = 0;
if ( USBTOI2C2_OK == usbtoi2c2_read_data ( &usbtoi2c2, &rx_data, 1 ) )
{
if ( USBTOI2C2_OK == usbtoi2c2_write_data ( &usbtoi2c2, &rx_data, 1 ) )
{
log_printf( &logger, "%c", rx_data );
}
}
}
int main ( void )
{
/* Do not remove this line or clock might not be set correctly. */
#ifdef PREINIT_SUPPORTED
preinit();
#endif
application_init( );
for ( ; ; )
{
application_task( );
}
return 0;
}
// ------------------------------------------------------------------------ END
