Transform conventional UART/RS232 into 1-Wire® signals with DS2480B and STM32F091RC
Streamline your data collection with one wire
Published Feb 26, 2024
Click board™
UART 1-Wire Click
Dev Board
Nucleo-64 with STM32F091RC MCU
Compiler
NECTO Studio
MCU
STM32F091RC
By utilizing a single data line for communication and choosing this type of conversion (1-Wire to UART), you will perform efficient and reliable data transfer without additional wiring
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Hardware Overview
How does it work?
UART 1-Wire Click is based on the DS2480B, a serial to the 1-Wire® driver from Analog Devices. This IC is designed to interface the UART with the 1-Wire® bus directly. It performs data conversion using independent data rates for both interfaces, allowing standard and overdrive communication speeds. Internal timing generators of the DS2480B IC are continuously synchronized with the incoming UART data, which is typically driven by a high-precision crystal oscillator of the host microcontroller (MCU). This allows time-critical 1-Wire® signals to be generated by the DS2480B, significantly reducing the processing load from the host MCU. Many physical parameters of the UART and 1-Wire® buses can be fine-tuned so that the UART 1-Wire click can be accommodated to any UART/RS232 to 1-Wire® signal conversion application. The DS2480B IC can be observed as a complex state machine. UART commands can configure it, so the IC must parse the
incoming data before conversion. The device can be operated in two main operating modes: Command Mode and Data Mode. The Command Mode is the default state after the Power ON event. This mode allows the configuration parameters to be set. However, the DS2480B IC must be initialized before any operation: the 1-Wire® bus reset command should be sent over the TXD line at a fixed rate of 9600 bps. This is used only to calibrate the internal timing generators without performing any action on the 1-Wire® bus. After the initialization, the DS2480B IC can be used normally. The Data Mode converts bytes received at the TXD line into their equivalent 1-Wire® waveforms and reports the responses back to the host MCU through the RXD line. The datasheet of the DS2480B IC illustrates the operating principles of this IC by using the state transition diagram. Along with several examples at the end of the datasheet, it represents a useful starting point for application
development. However, the included mikroSDK-compatible library offers functions that simplify firmware development even more. The DS2480B requires 5V for both the power supply and logic levels. Considering that most MCUs use 3.3V logic levels for UART communication, a level translator had to be added. UART 1-Wire click uses the TXB0106, a bi-directional level translator IC, by Texas Instruments. This IC allows reliable logic voltage level translation, allowing the Click board™ to be used with a wide range of MCUs that use 3.3V logic levels on their UART lines. The 1-Wire® bus can be accessed over the screw terminal on the Click board™. Due to the nature of most 1-Wire® applications, the signal line of the 1-Wire® bus is protected by the DS9503, an integrated ESD Protection Diode with resistors. This IC is specifically designed to be used as Electrostatic Discharge (ESD) protection in 1-Wire® applications.
Features overview
Development board
Nucleo-64 with STM32F091RC MCU offers a cost-effective and adaptable platform for developers to explore new ideas and prototype their designs. This board harnesses the versatility of the STM32 microcontroller, enabling users to select the optimal balance of performance and power consumption for their projects. It accommodates the STM32 microcontroller in the LQFP64 package and includes essential components such as a user LED, which doubles as an ARDUINO® signal, alongside user and reset push-buttons, and a 32.768kHz crystal oscillator for precise timing operations. Designed with expansion and flexibility in mind, the Nucleo-64 board features an ARDUINO® Uno V3 expansion connector and ST morpho extension pin
headers, granting complete access to the STM32's I/Os for comprehensive project integration. Power supply options are adaptable, supporting ST-LINK USB VBUS or external power sources, ensuring adaptability in various development environments. The board also has an on-board ST-LINK debugger/programmer with USB re-enumeration capability, simplifying the programming and debugging process. Moreover, the board is designed to simplify advanced development with its external SMPS for efficient Vcore logic supply, support for USB Device full speed or USB SNK/UFP full speed, and built-in cryptographic features, enhancing both the power efficiency and security of projects. Additional connectivity is
provided through dedicated connectors for external SMPS experimentation, a USB connector for the ST-LINK, and a MIPI® debug connector, expanding the possibilities for hardware interfacing and experimentation. Developers will find extensive support through comprehensive free software libraries and examples, courtesy of the STM32Cube MCU Package. This, combined with compatibility with a wide array of Integrated Development Environments (IDEs), including IAR Embedded Workbench®, MDK-ARM, and STM32CubeIDE, ensures a smooth and efficient development experience, allowing users to fully leverage the capabilities of the Nucleo-64 board in their projects.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M0
MCU Memory (KB)
256
Silicon Vendor
STMicroelectronics
Pin count
64
RAM (Bytes)
32768
You complete me!
Accessories
Click Shield for Nucleo-64 comes equipped with two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the STM32 Nucleo-64 board with no effort. This way, Mikroe allows its users to add any functionality from our ever-growing range of Click boards™, such as WiFi, GSM, GPS, Bluetooth, ZigBee, environmental sensors, LEDs, speech recognition, motor control, movement sensors, and many more. More than 1537 Click boards™, which can be stacked and integrated, are at your disposal. The STM32 Nucleo-64 boards are based on the microcontrollers in 64-pin packages, a 32-bit MCU with an ARM Cortex M4 processor operating at 84MHz, 512Kb Flash, and 96KB SRAM, divided into two regions where the top section represents the ST-Link/V2 debugger and programmer while the bottom section of the board is an actual development board. These boards are controlled and powered conveniently through a USB connection to program and efficiently debug the Nucleo-64 board out of the box, with an additional USB cable connected to the USB mini port on the board. Most of the STM32 microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the STM32 Nucleo-64 board with our Click Shield for Nucleo-64, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.
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 Nucleo-64 with STM32F091RC MCU 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 UART 1-Wire Click driver.
Key functions:
uart1wire_write_command- This function sends an 8-bit command to the click module.uart1wire_read_temperature- This function reads the temperature from DALLAS one wire temperature sensors.uart1wire_reset- This function sends a reset pulse signal.
Open Source
Code example
This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.
/*!
* \file
* \brief UART1Wire Click example
*
* # Description
* This example reads and processes data from UART 1-Wire clicks.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and logger.
*
* ## Application Task
* Reads the temperature data from DALLAS temperature sensors and logs the results
* on the USB UART every second.
*
* @note
* Connect only DQ and GND pins to the UART 1-Wire click connector.
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "uart1wire.h"
#include "string.h"
// ------------------------------------------------------------------ VARIABLES
static uart1wire_t uart1wire;
static log_t logger;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
uart1wire_cfg_t cfg;
/**
* 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.
uart1wire_cfg_setup( &cfg );
UART1WIRE_MAP_MIKROBUS( cfg, MIKROBUS_1 );
uart1wire_init( &uart1wire, &cfg );
Delay_ms( 100 );
}
void application_task ( void )
{
float temp_f;
uint8_t res_flag;
res_flag = uart1wire_read_temperature ( &uart1wire, &temp_f, UART1WIRE_TEMP_SENSOR_RESOLUTION_9BIT );
if ( res_flag == UART1WIRE_OK )
{
log_printf( &logger, " * Temperature: %.2f C\r\n", temp_f );
log_printf( &logger, "------------------------------\r\n" );
Delay_ms( 1000 );
}
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
