Our advanced transceiver seamlessly integrates with CXPI networks, empowering efficient and reliable automotive communication for optimal data exchange in demanding environments
A
A
Hardware Overview
How does it work?
CXPI Click is based on the BD41000AFJ-C, a transceiver for the Clock Extension Peripheral Interface (CXPI) communication from Rohm Semiconductor. The BD41000FJ-C complies with the CXPI standard established by JSAE (Society of Automotive Engineers of Japan), enabling highly responsive, reliable multiplex communication even in HMI systems, reducing vehicle weight and increasing fuel efficiency. The BD41000AFJ-C operates from 7V to 18V external power supply labeled as BAT and has several operating modes, each controlled by the CS pin of the mikroBUS™, BUS pin, and UART TX pin. It has built-in Power-OFF, Through, and RX Through other than CODEC Mode for power-saving control. Power-OFF Mode reduces power consumption by not supplying power to circuits other than necessary for Wake-Up pulse detection (BUS) and Wake-Up input
detection (TX). Through Mode does not process Coding/Decoding. It only directly drives signals from UART TX to BUS and from BUS to UART RX. RX Through Mode reverses RX output at each rising edge of BUS. CODEC Mode is the mode of CXPI communication. CS pin of the mikroBUS™ socket labeled as EN should be set high for the chip to enter CODEC Mode. The BD41000AFJ-C can achieve a quiescent 3uA (typ.) current, ensuring suitability with automotive applications. As a result, the battery load is minimized during non-operation, contributing to higher energy savings. Also, high ESD resistance (±8kV) makes achieving low-power, high-reliability CXPI communication possible. Besides, it has built-in fail-safe functions that suspend the output data upon detecting under-voltage or temperature abnormality. CXPI Click communicates
with MCU using the UART interface with a transmission speed range from 5kbps to 20kbps and commonly used UART RX and TX pins for data transfer. Also, it has three jumpers that allow the selection of CXPI transmitter mode on the MS pin of the BD41000AFJ-C to its appropriate position marked as Master or Slave. This can be performed by using the SMD jumpers labeled as MODE. Note that all the jumpers must be placed on the same side, or the Click board™ may become unresponsive. 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. Also, this 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
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.
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic

Step by step
Project 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 CXPI Click driver.
Key functions:
cxpi_send_command
- Send commandcxpi_set_pwm_pin_state
- Set PWM pin state functioncxpi_set_through_mode
- Set through mode function.
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 CXPI Click Example.
*
* # Description
* This is an example that demonstrates the use of the CXPI Click board.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes UART driver.
* In addition to this module is placed inside transmitter/receiver working mode
* cappable of transmission/receive the data.
*
* ## Application Task
* Transmitter/Receiver task depend on uncommented code
* Receiver logging each received byte to the UART for data logging,
* while transmitted send messages every 5 seconds.
*
* ## Additional Function
* - static void cxpi_clear_current_rsp_buf ( void )
* - static void cxpi_process ( void )
*
* @author Stefan Ilic
*
*/
#include "board.h"
#include "log.h"
#include "cxpi.h"
#define PROCESS_COUNTER 10
#define PROCESS_RX_BUFFER_SIZE 100
#define PROCESS_PARSER_BUFFER_SIZE 100
//#define DEMO_APP_RECEIVER
#define DEMO_APP_TRANSMITTER
static cxpi_t cxpi;
static log_t logger;
static char current_rsp_buf[ PROCESS_PARSER_BUFFER_SIZE ];
unsigned char demo_message[ 9 ] = { 'M', 'i', 'k', 'r', 'o', 'E', 13, 10, 0 };
/**
* @brief CXPI clearing application buffer.
* @details This function clears memory of application buffer and resets it's length and counter.
*/
static void cxpi_clear_current_rsp_buf ( void );
/**
* @brief CXPI data reading function.
* @details This function reads data from device and concatenates data to application buffer.
*/
static void cxpi_process ( void );
void application_init ( void ) {
log_cfg_t log_cfg; /**< Logger config object. */
cxpi_cfg_t cxpi_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 );
// Click initialization.
cxpi_cfg_setup( &cxpi_cfg );
CXPI_MAP_MIKROBUS( cxpi_cfg, MIKROBUS_1 );
err_t init_flag = cxpi_init( &cxpi, &cxpi_cfg );
if ( UART_ERROR == init_flag ) {
log_error( &logger, " Application Init Error. " );
log_info( &logger, " Please, run program again... " );
for ( ; ; );
}
log_info( &logger, " Application Task " );
cxpi_set_through_mode( &cxpi );
#ifdef DEMO_APP_TRANSMITTER
log_printf( &logger, "------------------\r\n" );
log_printf( &logger, " Send data: \r\n" );
log_printf( &logger, " MikroE \r\n" );
Delay_ms( 1000 );
#elif defined DEMO_APP_RECEIVER
log_printf( &logger, "------------------\r\n" );
log_printf( &logger, " Receive data \r\n" );
Delay_ms( 2000 );
#else
# error PLEASE SELECT TRANSMIT OR RECEIVE MODE!!!
#endif
log_printf( &logger, "------------------\r\n" );
}
void application_task ( void ) {
#ifdef DEMO_APP_TRANSMITTER
cxpi_send_command( &cxpi, &demo_message[ 0 ] );
log_printf( &logger, " Sent data : %s", &demo_message[ 0 ] );
log_printf( &logger, "------------------\r\n" );
Delay_ms( 5000 );
#elif defined DEMO_APP_RECEIVER
cxpi_process( );
if ( current_rsp_buf > 0 ) {
log_printf( &logger, "%s", current_rsp_buf );
cxpi_clear_current_rsp_buf( );
}
#else
# error PLEASE SELECT TRANSMIT OR RECEIVE MODE!!!
#endif
}
void main ( void ) {
application_init( );
for ( ; ; ) {
application_task( );
}
}
static void cxpi_clear_current_rsp_buf ( void ) {
memset( current_rsp_buf, 0, PROCESS_PARSER_BUFFER_SIZE );
}
static void cxpi_process ( void ) {
int16_t rsp_size;
uint16_t rsp_cnt = 0;
char uart_rx_buffer[ PROCESS_RX_BUFFER_SIZE ] = { 0 };
uint8_t check_buf_cnt;
uint8_t process_cnt = PROCESS_COUNTER;
// Clear parser buffer
memset( current_rsp_buf, 0 , PROCESS_PARSER_BUFFER_SIZE );
while( process_cnt != 0 ) {
rsp_size = cxpi_generic_read( &cxpi, &uart_rx_buffer, PROCESS_RX_BUFFER_SIZE );
if ( rsp_size > 0 ) {
// Validation of the received data
for ( check_buf_cnt = 0; check_buf_cnt < rsp_size; check_buf_cnt++ ) {
if ( uart_rx_buffer[ check_buf_cnt ] == 0 ) {
uart_rx_buffer[ check_buf_cnt ] = 13;
}
}
// Storages data in parser buffer
rsp_cnt += rsp_size;
if ( rsp_cnt < PROCESS_PARSER_BUFFER_SIZE ) {
strncat( current_rsp_buf, uart_rx_buffer, rsp_size );
}
// Clear RX buffer
memset( uart_rx_buffer, 0, PROCESS_RX_BUFFER_SIZE );
} else {
process_cnt--;
// Process delay
Delay_ms( 100 );
}
}
}
// ------------------------------------------------------------------------ END
Additional Support
Resources
Category:CXPI