Create systems that require secure, physical touchpoints for data transfer or user identification
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Hardware Overview
How does it work?
iButton Click is based on the CZ-0-PIN, a high-quality iButton probe from Demiurge. The metal probe ensures resistance to dirt, dust, moisture, shock, and other environmental hazards while ensuring good alignment with the iButton device. The manufacturer guarantees compatibility with Analog iButton devices, but the probe can read any other device compatible with the maxim iButton. The iButton device can power itself up through the data line by employing the so-called parasite power supply. This Click board™ is equipped with the pull-up resistor to the 3.3V mikroBUS™ rail, providing power for the iButton. The so-called parasite PSU of the iButton contains an internal capacitor, which
provides enough current for the proper operation once the data line has charged. To allow proper functioning of the parasitic PSU, the idle state of the data line is HIGH, while the data line of the iButton device is in an open-drain configuration, pulling the data line to a LOW logic level when asserted. The 1-Wire communication line is routed to the SMD jumper, which allows routing of the 1-Wire communication either to the PWM pin or to the AN pin of the mikroBUS™. These pins are labeled GP0 and GP1, respectively, the same as the SMD jumper positions, making the selection of the desired pin simple and straightforward. The green LED labeled as ST1 is routed to the RST pin of the
mikroBUS™, while the red LED is labeled as ST2 and is routed to the CS pin of the mikroBUS™. These two pins allow visual feedback from the software; for example, if the serial number of the docked iButton matches the authorization criteria, the green LED can signal it. These LEDs can be used for any signalization and are not directly connected to the iButton device. 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 for further development.
Features overview
Development board
Arduino UNO is a versatile microcontroller board built around the ATmega328P chip. It offers extensive connectivity options for various projects, featuring 14 digital input/output pins, six of which are PWM-capable, along with six analog inputs. Its core components include a 16MHz ceramic resonator, a USB connection, a power jack, an
ICSP header, and a reset button, providing everything necessary to power and program the board. The Uno is ready to go, whether connected to a computer via USB or powered by an AC-to-DC adapter or battery. As the first USB Arduino board, it serves as the benchmark for the Arduino platform, with "Uno" symbolizing its status as the
first in a series. This name choice, meaning "one" in Italian, commemorates the launch of Arduino Software (IDE) 1.0. Initially introduced alongside version 1.0 of the Arduino Software (IDE), the Uno has since become the foundational model for subsequent Arduino releases, embodying the platform's evolution.
Microcontroller Overview
MCU Card / MCU
Architecture
AVR
MCU Memory (KB)
32
Silicon Vendor
Microchip
Pin count
28
RAM (Bytes)
2048
You complete me!
Accessories
Click Shield for Arduino UNO has two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the Arduino UNO board without effort. The Arduino Uno, a microcontroller board based on the ATmega328P, provides an affordable and flexible way for users to try out new concepts and build prototypes with the ATmega328P microcontroller from various combinations of performance, power consumption, and features. The Arduino Uno has 14 digital input/output pins (of which six can be used as PWM outputs), six analog inputs, a 16 MHz ceramic resonator (CSTCE16M0V53-R0), a USB connection, a power jack, an ICSP header, and reset button. Most of the ATmega328P 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 Arduino UNO board with our Click Shield for Arduino UNO, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.
The DS1990A is a unique serial number identification iButton™. The iButton is a technology based on the one-wire communication protocol and a chip packed in a robust stainless steel casing. This button-shaped device has two contacts - the lid and the base. These contacts carry the necessary connections down to a sensitive silicone chip embedded inside the metal button. When the iButton touches the reader probe, it establishes the communication with the host MCU via the one-wire interface. The communication is almost instant, so pressing the iButton lightly to the probe contacts is enough.
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Schematic
Step by step
Project assembly
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 iButton Click driver.
Key functions:
ibutton_add_key
- This function reads the ROM address from a DS1990A Serial Number iButton and stores it in the ctx->key_rom buffeributton_remove_keys
- This function removes all stored keys by clearing the ctx->key_rom buffeributton_check_key
- This function reads the ROM address from a DS1990A Serial Number iButton and checks if it is already stored in the ctx->key_rom buffer
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 main.c
* @brief iButton Click Example.
*
* # Description
* This example demonstrates the use of the iButton click boards by registering a DS1990A Serial Number iButton
* key and then waiting until a key is detected on the reader and identifying if the key matches one of
* those stored in RAM.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and registers a new DS1990A Serial Number iButton key and stores it in RAM.
*
* ## Application Task
* Waits until a key is detected on the reader, and checks if there's a key found in the library that matches
* the one it has just read. All data is being logged on the USB UART where you can track the program flow.
*
* @author Stefan Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "ibutton.h"
#define NUMBER_OF_KEYS 1 // Number of keys to register.
static ibutton_t ibutton;
static log_t logger;
/**
* @brief iButton led indication function.
* @details This function indicates the selected state over LEDs indication.
* @param[in] ctx : Click context object.
* See #ibutton_t object definition for detailed explanation.
* @param[in] state : @li @c 0 - Disable LEDs.
* @li @c 1 - Wait for a key.
* @li @c 2 - Operation successfull.
* @li @c 3 - Wrong key found.
* @return None.
* @note None.
*/
static void ibutton_led_indication ( ibutton_t *ctx, ibutton_led_state_t state );
/**
* @brief iButton register keys function.
* @details This function registers a desired number of keys.
* Each step will be logged on the USB UART where you can track the function flow.
* @param[in] ctx : Click context object.
* See #ibutton_t object definition for detailed explanation.
* @param[in] num_keys : Number of keys to register.
* @return None.
* @note None.
*/
static void ibutton_register_keys ( ibutton_t *ctx, uint8_t num_keys );
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
ibutton_cfg_t ibutton_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.
ibutton_cfg_setup( &ibutton_cfg );
IBUTTON_MAP_MIKROBUS( ibutton_cfg, MIKROBUS_1 );
if ( ONE_WIRE_ERROR == ibutton_init( &ibutton, &ibutton_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
ibutton_register_keys ( &ibutton, NUMBER_OF_KEYS );
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
err_t error_flag = IBUTTON_OK;
ibutton_led_indication ( &ibutton, IBUTTON_LED_DISABLE );
log_printf( &logger, " >>> Waiting for a key <<<\r\n" );
do
{
ibutton_led_indication ( &ibutton, IBUTTON_LED_WAIT_KEY );
error_flag = ibutton_check_key ( &ibutton );
}
while ( IBUTTON_ERROR == error_flag );
ibutton_led_indication ( &ibutton, IBUTTON_LED_DISABLE );
if ( IBUTTON_OK == error_flag )
{
log_printf( &logger, " MATCH, access allowed!\r\n" );
ibutton_led_indication ( &ibutton, IBUTTON_LED_SUCCESS );
}
else if ( IBUTTON_KEY_NO_MATCH == error_flag )
{
log_printf( &logger, " NO MATCH, access denied!\r\n" );
ibutton_led_indication ( &ibutton, IBUTTON_LED_WRONG_KEY );
}
ibutton_led_indication ( &ibutton, IBUTTON_LED_DISABLE );
log_printf( &logger, "--------------------------------\r\n\n" );
Delay_ms ( 500 );
}
int main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
return 0;
}
static void ibutton_led_indication ( ibutton_t *ctx, ibutton_led_state_t state )
{
switch ( state )
{
case IBUTTON_LED_DISABLE:
{
ibutton_disable_green_led ( ctx );
ibutton_disable_red_led ( ctx );
break;
}
case IBUTTON_LED_WAIT_KEY:
{
ibutton_enable_green_led ( &ibutton );
Delay_ms ( 250 );
ibutton_disable_green_led ( &ibutton );
ibutton_enable_red_led ( &ibutton );
Delay_ms ( 250 );
ibutton_disable_red_led ( &ibutton );
break;
}
case IBUTTON_LED_SUCCESS:
{
ibutton_enable_green_led ( &ibutton );
Delay_ms ( 250 );
ibutton_disable_green_led ( &ibutton );
Delay_ms ( 250 );
ibutton_enable_green_led ( &ibutton );
Delay_ms ( 250 );
ibutton_disable_green_led ( &ibutton );
Delay_ms ( 250 );
break;
}
case IBUTTON_LED_WRONG_KEY:
{
ibutton_enable_red_led ( &ibutton );
Delay_ms ( 250 );
ibutton_disable_red_led ( &ibutton );
Delay_ms ( 250 );
ibutton_enable_red_led ( &ibutton );
Delay_ms ( 250 );
ibutton_disable_red_led ( &ibutton );
Delay_ms ( 250 );
break;
}
default:
{
break;
}
}
}
static void ibutton_register_keys ( ibutton_t *ctx, uint8_t num_keys )
{
err_t error_flag = IBUTTON_OK;
uint8_t key_cnt = 1;
while ( key_cnt <= num_keys )
{
ibutton_led_indication ( &ibutton, IBUTTON_LED_DISABLE );
log_printf( &logger, " >>> Registering key %u of %u <<<\r\n", ( uint16_t ) key_cnt, ( uint16_t ) num_keys );
log_printf( &logger, " Insert a DS1990A Serial Number iButton to click board reader plate\r\n" );
do
{
ibutton_led_indication ( &ibutton, IBUTTON_LED_WAIT_KEY );
error_flag = ibutton_add_key ( &ibutton );
}
while ( IBUTTON_ERROR == error_flag );
ibutton_led_indication ( &ibutton, IBUTTON_LED_DISABLE );
if ( IBUTTON_KEY_ALREADY_EXIST == error_flag )
{
log_printf( &logger, " This key is already registered!\r\n" );
log_printf( &logger, " Use another key or decrease the number of keys\r\n" );
ibutton_led_indication ( &ibutton, IBUTTON_LED_WRONG_KEY );
}
else if ( IBUTTON_OK == error_flag )
{
log_printf( &logger, " The key is registered successfully!\r\n" );
ibutton_led_indication ( &ibutton, IBUTTON_LED_SUCCESS );
key_cnt++;
}
ibutton_led_indication ( &ibutton, IBUTTON_LED_DISABLE );
log_printf( &logger, "--------------------------------\r\n\n" );
Delay_ms ( 500 );
}
}
// ------------------------------------------------------------------------ END