Bridge the gap between I2C communication and the 1-Wire interface with DS28E17 and PIC18F25K80

Simplify wiring and extend the reach of I2C devices across your projects

Published Mar 15, 2024

Click board™

1-Wire I2C click

Dev. board

EasyPIC v8

Compiler

NECTO Studio

MCU

PIC18F25K80

Allow devices that traditionally communicate over I2C to be connected and interact over a 1-Wire interface

Hardware Overview

How does it work?

1-Wire I2C Click is based on the DS28E17, a 1-Wire-to-I2C master bridge from Analog Devices. The bridge supports 15Kbps and 77Kbps 1-Wire protocol with packetized I2C data payloads. The factory-programmed unique 64-bit 1-Wire ROM ID provides an unalterable serial number to the end equipment, thus allowing multiple DS8E17 devices to coexist with other devices in a 1-Wire network and be accessed individually without affecting other devices. The 1-Wire I2C Click allows

communication with complex I2C devices, such as displays, ADCs, DACs, sensors, and more. The bridge provides 1-Wire communication with only one I2C device. 1-Wire I2C Click uses the 1-Wire interface as a bridge to the standard 2-Wire I2C interface to communicate with the host MCU. You can choose a One-Wire input pin over the OW SEL jumper, where the OW1 is routed to an analog pin of the mikroBUS™ socket and is set by default. You can also reset the bridge over the RST pin. The I2C

device can be connected over a 4-pin screw terminal. 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, this Click board™ comes equipped with a library containing functions and an example code that can be used as a reference for further development.

1-Wire I2C click hardware overview image

Features overview

Development board

EasyPIC v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports many high pin count 8-bit PIC microcontrollers from Microchip, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. Thanks to innovative manufacturing technology, EasyPIC v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the EasyPIC v8 development board contains the components necessary for the most efficient operation of the same board. In addition to the advanced integrated CODEGRIP programmer/debugger module, which offers many valuable programming/debugging options and seamless integration with the Mikroe software environment, the board also includes a clean and regulated power supply module for the development board. It can use a wide range of external power sources, including a battery, an external 12V power supply, and a power source via the USB Type-C (USB-C) connector.

Communication options such as USB-UART, USB DEVICE, and CAN are also included, including the well-established mikroBUS™ standard, two display options (graphical and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 8-bit PIC MCUs, from the smallest PIC MCU devices with only eight up to forty pins. EasyPIC v8 is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

Microcontroller Overview

MCU Card / MCU

Architecture

PIC

MCU Memory (KB)

Silicon Vendor

Microchip

Pin count

RAM (Bytes)

3648

Used MCU Pins

mikroBUS™ mapper

1-Wire Data IN/OUT

RA3

Reset

RA0

RST

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

1-Wire Data IN/OUT

RC1

PWM

INT

SCL

SDA

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

EasyPIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v8 as your development board.

NECTO Output Selection Step Image hardware assembly

In the advanced settings, pay special attention to the Redirect standard output field. By default, it is set to Application output as the method of displaying final results. To show results via a UART terminal, select the “UART” option in that field and click the “SAVE” button. You will be returned to the Compiler field, and now you can move on to the next step by pressing the “NEXT” button.

GNSS2 Click front image hardware assembly

GNSS2 Click complete accessories setup image hardware assembly

EasyPIC v8 Access DIPMB 1 - upright/background hardware assembly

NECTO Compiler Selection Step Image hardware assembly

Necto DIP image step 7 hardware assembly

Software Support

Library Description

This library contains API for 1-Wire I2C Click driver.

Key functions:

c1wirei2c_reset_device - This function resets the device by toggling the RST pin state
c1wirei2c_write_data - This function addresses and writes 1-255 bytes to an I2C slave without completing the transaction with a stop
c1wirei2c_read_data_stop - This function is used to address and read 1-255 bytes from an I2C slave in one transaction

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 1-Wire I2C Click Example.
 *
 * # Description
 * This example demonstrates the use of 1-Wire I2C Click board by reading
 * the temperature measurement from connected Thermo 4 Click board.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and performs the Click default configuration.
 *
 * ## Application Task
 * Reads the temperature measurement from connected Thermo 4 Click board and
 * displays the results on the USB UART once per second.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "c1wirei2c.h"

// Thermo 4 device settings
#define DEVICE_NAME                "Thermo 4 Click"
#define DEVICE_SLAVE_ADDRESS       0x48
#define DEVICE_REG_TEMPERATURE     0x00
#define DEVICE_TEMPERATURE_RES     0.125f

static c1wirei2c_t c1wirei2c;
static log_t logger;

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    c1wirei2c_cfg_t c1wirei2c_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.
    c1wirei2c_cfg_setup( &c1wirei2c_cfg );
    C1WIREI2C_MAP_MIKROBUS( c1wirei2c_cfg, MIKROBUS_1 );
    if ( ONE_WIRE_ERROR == c1wirei2c_init( &c1wirei2c, &c1wirei2c_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( C1WIREI2C_ERROR == c1wirei2c_default_cfg ( &c1wirei2c ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    float temperature = 0;
    uint8_t reg_data[ 2 ] = { 0 };
    uint8_t reg_addr = DEVICE_REG_TEMPERATURE;
    if ( ( C1WIREI2C_OK == c1wirei2c_write_data ( &c1wirei2c, DEVICE_SLAVE_ADDRESS, &reg_addr, 1 ) ) && 
         ( C1WIREI2C_OK == c1wirei2c_read_data_stop ( &c1wirei2c, DEVICE_SLAVE_ADDRESS, reg_data, 2 ) ) )
    {
        temperature = ( ( ( int16_t ) ( ( ( uint16_t ) reg_data[ 0 ] << 8 ) | 
                                                       reg_data[ 1 ] ) ) >> 5 ) * DEVICE_TEMPERATURE_RES;
        log_printf( &logger, "\r\n%s - Temperature: %.3f degC\r\n", ( char * ) DEVICE_NAME, temperature );
    }
    else
    {
        log_error( &logger, "%s - no communication!\r\n", ( char * ) DEVICE_NAME );
    }
    Delay_ms ( 1000 );
}

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