Intermediate
30 min

Experience the magic of protocol transformation with SC18IM704 and STM32F031K6

UART to I2C wizardry: Your communication transformer!

UART to I2C Click with Nucleo 32 with STM32F031K6 MCU

Published Oct 01, 2024

Click board™

UART to I2C Click

Dev. board

Nucleo 32 with STM32F031K6 MCU

Compiler

NECTO Studio

MCU

STM32F031K6

Unlock the potential of your UART devices by effortlessly integrating them into I2C networks using our transformation solution, simplifying data exchange and enhancing control

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Hardware Overview

How does it work?

UART to I2C Click is based on the SC18IM704, a bridge between the standard UART port and a serial I2C bus from NXP Semiconductors. The SC18IM704 consists of a full-functional advanced UART interface that communicates with the host MCU through the commonly used RX and TX pins of the mikroBUS™ socket. It is also characterized by a high baud rate of up to 460.8 kbit/s and 256-byte FIFO for the transfer/receive data process. The serial data format is fixed to a one start bit, 8 data bits, and one stop bit. After the reset feature, the baud rate defaults to 9600 bit/s and can be changed through the Baud Rate Generator (BRG) registers. After a Power-Up sequence or already-mentioned hardware reset, achievable through the RST pin of the mikroBUS™ socket, the

SC18IM704 will send two continuous bytes to the host MCU to indicate a Start-Up condition. These two continuous bytes are 0x4F and 0x4B, representing an ‘OK’ state in the ASCII messages protocol. After the correct initial sequence, direct communication is enabled with other I2C-bus devices connected to the populated I2C-bus terminal. The I2C bus uses two wires (SCL and SDA) to transfer information between connected devices, providing a byte-oriented interface that supports data transfers up to 400kHz. The SC18IM704 can also be placed in a software-configurable low-power mode (Power-Down mode). Upon entering the Power-Down state, the UART RX pin is used to exit Deep Power-down mode. The bridge remains in the Deep

Power-down mode as long as the RX pin remains in a high logic state. Any character sent brings the bridge out of Deep Power-down mode but ignores the character. In addition to all these features, the SC18IM704 has several general-purpose I/O pins on the populated header with labeled GP pins. These pins have the option of software setting their function as push-pull, open-drain, or input-only. This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it comes equipped with a library containing functions and an example code that can be used as a reference for further development.

UART to I2C Click top side image
UART to I2C Click bottom side image

Features overview

Development board

Nucleo 32 with STM32F031K6 MCU board provides an affordable and flexible platform for experimenting with STM32 microcontrollers in 32-pin packages. Featuring Arduino™ Nano connectivity, it allows easy expansion with specialized shields, while being mbed-enabled for seamless integration with online resources. The

board includes an on-board ST-LINK/V2-1 debugger/programmer, supporting USB reenumeration with three interfaces: Virtual Com port, mass storage, and debug port. It offers a flexible power supply through either USB VBUS or an external source. Additionally, it includes three LEDs (LD1 for USB communication, LD2 for power,

and LD3 as a user LED) and a reset push button. The STM32 Nucleo-32 board is supported by various Integrated Development Environments (IDEs) such as IAR™, Keil®, and GCC-based IDEs like AC6 SW4STM32, making it a versatile tool for developers.

Nucleo 32 with STM32F031K6 MCU double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

ARM Cortex-M0

MCU Memory (KB)

32

Silicon Vendor

STMicroelectronics

Pin count

32

RAM (Bytes)

4096

You complete me!

Accessories

Click Shield for Nucleo-32 is the perfect way to expand your development board's functionalities with STM32 Nucleo-32 pinout. The Click Shield for Nucleo-32 provides two mikroBUS™ sockets to add any functionality from our ever-growing range of Click boards™. We are fully stocked with everything, from sensors and WiFi transceivers to motor control and audio amplifiers. The Click Shield for Nucleo-32 is compatible with the STM32 Nucleo-32 board, providing an affordable and flexible way for users to try out new ideas and quickly create prototypes with any STM32 microcontrollers, choosing from the various combinations of performance, power consumption, and features. The STM32 Nucleo-32 boards do not require any separate probe as they integrate the ST-LINK/V2-1 debugger/programmer and come with the STM32 comprehensive software HAL library and various packaged software examples. This development platform provides users with an effortless and common way to combine the STM32 Nucleo-32 footprint compatible board with their favorite Click boards™ in their upcoming projects.

Click Shield for Nucleo-32 accessories 1 image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset
PA11
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
UART TX
PA10
TX
UART RX
PA9
RX
NC
NC
SCL
NC
NC
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

UART to I2C Click Schematic schematic

Step by step

Project assembly

Click Shield for Nucleo-144 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Nucleo 32 with STM32F031K6 MCU as your development board.

Click Shield for Nucleo-144 front image hardware assembly
Nucleo 144 with STM32L4A6ZG MCU front image hardware assembly
Stepper 22 Click front image hardware assembly
Prog-cut hardware assembly
Stepper 22 Click complete accessories setup image hardware assembly
Board mapper by product8 hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
Necto image step 5 hardware assembly
Necto image step 6 hardware assembly
STM32 M4 Clicker HA MCU/Select Step hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Debug Image Necto Step hardware assembly

Track your results in real time

Application Output

1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.

2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.

3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.

Software Support

Library Description

This library contains API for UART to I2C Click driver.

Key functions:

  • uarttoi2c_gpio_write - This function writes a desired data to the gpio port

  • uarttoi2c_gpio_read - This function reads data from the gpio port

  • uarttoi2c_i2c_write_then_read - This function performs a write then read with a repeated start to the I2C target device.

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 UART to I2C Click Example.
 *
 * # Description
 * This example demonstrates the use of USB to I2C click board by reading the device ID
 * of a 3D Hall 11 click board connected to the I2C port and controlling the GPIO pins.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and performs the click default config which resets
 * the device and sets the GPIO pins 0-3 as push-pull output and others as input.
 * After that, reads and displays the chip firmware version.
 *
 * ## Application Task
 * Reads the device ID of a 3D Hall 11 click board connected to the I2C port, 
 * toggles the output pins and displays the GPIO port state. The results will
 * be displayed on the USB UART approximately once per second.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "uarttoi2c.h"

// I2C target device configuration
#define DEVICE_NAME                 "3D Hall 11 click"
#define DEVICE_SLAVE_ADDRESS        0x35
#define DEVICE_REG_ID               0x0D
#define DEVICE_ID                   0x01

static uarttoi2c_t uarttoi2c;
static log_t logger;

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    uarttoi2c_cfg_t uarttoi2c_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.
    uarttoi2c_cfg_setup( &uarttoi2c_cfg );
    UARTTOI2C_MAP_MIKROBUS( uarttoi2c_cfg, MIKROBUS_1 );
    if ( UART_ERROR == uarttoi2c_init( &uarttoi2c, &uarttoi2c_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( UARTTOI2C_ERROR == uarttoi2c_default_cfg ( &uarttoi2c ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    uint8_t version[ 16 ] = { 0 };
    if ( UARTTOI2C_OK == uarttoi2c_read_version ( &uarttoi2c, version ) )
    {
        log_printf( &logger, " Firmware version: %s\r\n", version );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    static uint8_t gpio_state = UARTTOI2C_NO_PIN_MASK;
    uint8_t slave_address = DEVICE_SLAVE_ADDRESS;
    uint8_t reg_addr = DEVICE_REG_ID;
    uint8_t device_id;
    if ( UARTTOI2C_OK == uarttoi2c_i2c_write_then_read ( &uarttoi2c, slave_address, 
                                                         &reg_addr, 1, &device_id, 1 ) )
    {
        log_printf( &logger, " %s - Device ID read: %s\r\n", ( char * ) DEVICE_NAME,
                    ( char * ) ( ( DEVICE_ID == device_id ) ? "Success" : "Fail" ) );
    }
    uarttoi2c_gpio_write ( &uarttoi2c, gpio_state );
    if ( UARTTOI2C_OK == uarttoi2c_gpio_read ( &uarttoi2c, &gpio_state ) )
    {
        log_printf( &logger, " GPIO state: 0x%.2X\r\n\n", ( uint16_t ) gpio_state );
        gpio_state = ~gpio_state;
    }
    Delay_ms ( 1000 );
}

void main ( void ) 
{
    application_init( );

    for ( ; ; ) 
    {
        application_task( );
    }
}

// ------------------------------------------------------------------------ END

Additional Support

Resources

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