Intermediate
30 min

Make a secure connection between interfaces with SC18IS602B and PIC32MZ1024EFH064

I2C Meets SPI: The revolutionary interface bridge solution!

I2C to SPI Click with PIC32MZ clicker

Published Sep 21, 2023

Click board™

I2C to SPI Click

Dev Board

PIC32MZ clicker

Compiler

NECTO Studio

MCU

PIC32MZ1024EFH064

Transform your projects with interface precision, as our bridge technology allows you to bridge the gap between I2C and SPI, optimizing data exchange, reducing complexity, and enhancing compatibility within your electronic applications

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Hardware Overview

How does it work?

I2C to SPI Click is based on two SC18IS602B, an I2C-bus to SPI bridge from NXP Semiconductor. This IC bridges the data communication between the two interfaces, offering many additional features, such as the programmable I/O, internal oscillator option, active low interrupt output, low power mode, and more. The SC18IS602B operates as an I2C-bus slave-transmitter or slave-receiver and an SPI master. The SC18IS602B controls all the SPI bus-specific sequences, protocol, and timing. It also has its own internal oscillator, and it supports SPI chip select output that may be configured as GPIO when not used. This allows the software to be easily written or ported from another platform. The I2C to SPI Click provides a byte-oriented I2C-bus interface that supports data transfers up to 400 kHz. When the I2C-bus master is reading data from the click board™, the device will be a slave-transmitter. It also can be a slave-receiver when the I2C-bus master is sending data. The SC18IS602B acts as an I2C-bus master at no time. However, it does have the ability to hold the SCL

line LOW between bytes to complete its internal processes. A slave address of the SC18IS602B is comprised of a fixed and a programmable part. The programmable part of the slave address enables the maximum possible number of such devices to be connected to the I2C-bus. Since the SC18IS602B has three programmable address bits (defined by the A2, A1, and A0 pins), it is possible to have eight of these devices on the same bus. Therefore, this Click board™ is equipped with three SMD jumpers, grouped under the ADDR SEL label, used to select the I2C slave address. By moving the jumpers at the desired position, the user can select the address used for the communication with the host MCU. The #RESET pin performs the hardware reset of the SC18IS602B IC. The #RESET pin is routed to the mikroBUS™ RST pin and it is active LOW. The #INT allows the host MCU to receive an interrupt from the SC18IS602B IC. An interrupt is generated by the SC18IS602B after any SPI transmission has been completed. Therefore, the #INT of the

SC18IS602B is routed to the INT pin of the mikroBUS™ socket. The interrupt can be cleared (INT pin HIGH) by sending a ‘Clear Interrupt’ command, although It is not necessary. This allows more optimized software (firmware) to be written, as the host MCU does not have to continuously poll the LSR register to see if any interrupt needs to be serviced. The datasheet of the SC18IS602B offers more information about using and configuring the SC18IS602B IC. However, the Click board™ is supported by a mikroSDK library, offering functions that simplify the prototyping and firmware development. 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.

I2C to SPI Click top side image
I2C to SPI Click bottom side image

Features overview

Development board

PIC32MZ Clicker is a compact starter development board that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It comes with an onboard 32-bit PIC32MZ microcontroller with FPU from Microchip, a USB connector, LED indicators, buttons, a mikroProg connector, and a header for interfacing with external electronics. Thanks to its compact design with clear and easy-recognizable silkscreen markings, it provides a fluid and immersive working experience, allowing access anywhere and under

any circumstances. Each part of the PIC32MZ Clicker development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the PIC32MZ Clicker programming method, using USB HID mikroBootloader, or through an external mikroProg connector for PIC, dsPIC, or PIC32 programmer, the Clicker board also includes a clean and regulated power supply module for the development kit. The USB Micro-B connection can provide up to 500mA of current, which is more than enough to operate all onboard

and additional modules. All communication methods that mikroBUS™ itself supports are on this board, including the well-established mikroBUS™ socket, reset button, and several buttons and LED indicators. PIC32MZ Clicker is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

PIC32MZ clicker double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC32

MCU Memory (KB)

1024

Silicon Vendor

Microchip

Pin count

64

RAM (Bytes)

524288

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset
RE5
RST
SPI Chip Select
RG9
CS
SPI Clock
RG6
SCK
SPI Data OUT
RG7
MISO
SPI Data IN
RG8
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Interrupt
RB5
INT
NC
NC
TX
NC
NC
RX
I2C Clock
RD10
SCL
I2C Data
RD9
SDA
NC
NC
5V
Ground
GND
GND
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Take a closer look

Schematic

I2C to SPI Click Schematic schematic

Step by step

Project assembly

PIC32MZ clicker front image hardware assembly

Start by selecting your development board and Click board™. Begin with the PIC32MZ clicker as your development board.

PIC32MZ clicker front image hardware assembly
Thermo 26 Click front image hardware assembly
Prog-cut hardware assembly
Micro B Connector clicker - upright/background 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
Flip&Click PIC32MZ MCU 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 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.

DEBUG_Application_Output

Software Support

Library Description

This library contains API for I2C to SPI Click driver.

Key functions:

  • i2ctospi_spi_write_byte - Function SPI write the byte of data to the targeted 8-bit register address of the SC18IS602B I2C-bus to SPI bridge on the I2C to SPI Click

  • i2ctospi_spi_read_byte - Function SPI read the byte of data from the targeted 8-bit register address of the SC18IS602B I2C-bus to SPI bridge on the I2C to SPI Click

  • i2ctospi_clear_interrupt - Function clear interrupt is generated by the SC18IS602B after any SPI transmission has been completed

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 I2cToSpi Click example
 * 
 * # Description
 * I2C to SPi Click allows serving as an interface between a standard I2C-bus of a microcontroller 
 * and an SPi bus, which allows the microcontroller to communicate directly with SPi devices 
 * through its I2C-bus. By offering an I2C-bus slave-transmitter or slave-receiver and SPI master, 
 * this Click controls all the SPi bus-specific sequences, protocol, and timing. It also has its own 
 * internal oscillator, and it supports the SPi chip select output that may be configured as GPIO when not used.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initialization driver enable's - I2C,
 * hardware reset, SS0 ( CS ) configured to be used as slave select outputs, set the configuration of SPI:
 * order MSB first, clock Idle low, leading-edge transition, SPI clock rate to 115kHz,
 * set SPI EEPROM write enable SS0, clear  interrupt,
 * clear RT5 register, sets starting time: hours, minutes and seconds ( enable counting ), also write log.
 * 
 * ## Application Task  
 * This is an example which demonstrates the use of RTC 5 click is wired to I2C to SPI click board.
 * I2C to SPI click communicates with register via the I2C interface,
 * serve as an interface between a standard I2C-bus of a microcontroller and an SPI bus.
 * RTC 5 click communicates with register via SPI interface.
 * In this examples, we display RTC time which we received reading from the target register 
 * address of MCP79510 chip on RTC 5 click board via I2C interface of I2C to SPI click board.
 * Results are being sent to the Usart Terminal where you can track their changes.
 * All data logs write on usb uart changes for every 1 sec.
 * 
 * *note:* 
 * <pre>
 * Additional Functions :
 *  - void display_log_uart( uint8_t value ) - Write the value of time or date as a two-digit number.
 *  - void rtc5_clear( i2ctospi_t *ctx, i2ctospi_spi_t *spi ) - Clear RTCC and SRAM memory of RTC 5 click.
 *  - void rtc5_set_time_seconds( i2ctospi_t *ctx, i2ctospi_spi_t *spi, uint8_t seconds ) - Set the seconds and enable counting.
 *  - uint8_t rtc5_get_time_seconds( i2ctospi_t *ctx, i2ctospi_spi_t *spi ) - Get the seconds.
 *  - void rtc5_set_time_minutes( uint8_t minutes ) - Set the minutes.
 *  - uint8_t rtc5_get_time_minutes( i2ctospi_t *ctx, i2ctospi_spi_t *spi ) - Get the minutes.
 *  - void rtc5_set_time_hours( i2ctospi_t *ctx, i2ctospi_spi_t *spi, uint8_t hours ) - Set the hours.
 *  - uint8_t rtc5_get_time_hours( i2ctospi_t *ctx, i2ctospi_spi_t *spi ) - Get the hours.
 * </pre>
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "i2ctospi.h"

// ------------------------------------------------------------------ VARIABLES

static i2ctospi_t i2ctospi;
static i2ctospi_spi_t i2ctospi_spi;
static i2ctospi_gpio_t i2ctospi_gpio;
static log_t logger;

static uint8_t time_hours;
static uint8_t time_minutes;
static uint8_t time_seconds;
static uint8_t time_seconds_new = 0xFF;

// ------------------------------------------------------- ADDITIONAL FUNCTIONS

void display_log_uart ( uint8_t value )
{
    log_printf( &logger, " %d%d ", ( uint16_t )( value / 10 ), ( uint16_t )( value % 10 ) );
}

void rtc5_clear ( i2ctospi_t *ctx, i2ctospi_spi_t *spi )
{
    uint8_t reg_add;
    
    spi->slave_device = I2CTOSPI_SLAVEDEVICE_SS0;
    spi->function_id = I2CTOSPI_RTC5_COMMAND_WRITE;
    spi->reg_addr = reg_add;

    for ( reg_add = 0; reg_add < 0x20; reg_add++ )
    {
        i2ctospi_spi_write_byte( ctx, spi, 0x00 );
        Delay_1us( );
    }

    spi->reg_addr = I2CTOSPI_RTC5_COMMAND_CLEAR;
    i2ctospi_spi_write_byte( ctx, spi, 0x00 );

    i2ctospi_clear_interrupt( ctx );
}

void rtc5_set_time_seconds ( i2ctospi_t *ctx, i2ctospi_spi_t *spi, uint8_t seconds )
{
    uint8_t ones;
    uint8_t tens;
    uint8_t temp;

    ones = 0x00;
    tens = 0x00;

    seconds %= 60;

    ones = seconds % 10;

    tens = ( seconds / 10 ) << 4;

    temp = tens | ones;
    temp |= I2CTOSPI_RTC5_COMMAND_ENABLE_COUNTING;

    spi->slave_device = I2CTOSPI_SLAVEDEVICE_SS0;
    spi->function_id = I2CTOSPI_RTC5_COMMAND_WRITE;
    spi->reg_addr = I2CTOSPI_RTC5_REG_TIME_SEC;

    i2ctospi_spi_write_byte( ctx, spi, temp );
}

uint8_t rtc5_get_time_seconds ( i2ctospi_t *ctx, i2ctospi_spi_t *spi )
{
    uint8_t ones;
    uint8_t tens;
    uint8_t result_sec;
    uint8_t temp;

    spi->slave_device = I2CTOSPI_SLAVEDEVICE_SS0;
    spi->function_id = I2CTOSPI_RTC5_COMMAND_READ;
    spi->reg_addr = I2CTOSPI_RTC5_REG_TIME_SEC;

    temp = i2ctospi_spi_read_byte( ctx, spi );

    ones = temp & 0x0F;

    tens = ( temp & 0x70 ) >> 4;

    result_sec = ( 10 * tens ) + ones;

    return result_sec;
}

void rtc5_set_time_minutes ( i2ctospi_t *ctx, i2ctospi_spi_t *spi, uint8_t minutes )
{
    uint8_t ones;
    uint8_t tens;
    uint8_t temp;

    ones = 0x00;
    tens = 0x00;

    minutes %= 60;

    ones = minutes % 10;

    tens = ( minutes / 10 ) << 4;

    temp = tens | ones;

    spi->slave_device = I2CTOSPI_SLAVEDEVICE_SS0;
    spi->function_id = I2CTOSPI_RTC5_COMMAND_WRITE;
    spi->reg_addr = I2CTOSPI_RTC5_REG_TIME_MIN;

    i2ctospi_spi_write_byte( ctx, spi, temp );
}

uint8_t rtc5_get_time_minutes ( i2ctospi_t *ctx, i2ctospi_spi_t *spi )
{
    uint8_t ones;
    uint8_t tens;
    uint8_t result_min;
    uint8_t temp;

    spi->slave_device = I2CTOSPI_SLAVEDEVICE_SS0;
    spi->function_id = I2CTOSPI_RTC5_COMMAND_READ;
    spi->reg_addr = I2CTOSPI_RTC5_REG_TIME_MIN;

    temp = i2ctospi_spi_read_byte( ctx, spi );

    ones = temp & 0x0F;

    tens = ( temp & 0x70 ) >> 4;

    result_min = ( 10 * tens ) + ones;

    return result_min;
}

void rtc5_set_time_hours ( i2ctospi_t *ctx, i2ctospi_spi_t *spi, uint8_t hours )
{
    uint8_t ones;
    uint8_t tens;
    uint8_t temp;

    ones = 0x00;
    tens = 0x00;

    hours %= 24;

    ones = hours % 10;

    tens = ( hours / 10 ) << 4;

    temp = tens | ones;

    spi->slave_device = I2CTOSPI_SLAVEDEVICE_SS0;
    spi->function_id = I2CTOSPI_RTC5_COMMAND_WRITE;
    spi->reg_addr = I2CTOSPI_RTC5_REG_TIME_HOUR,

    i2ctospi_spi_write_byte( ctx, spi, temp );
}

uint8_t rtc5_get_time_hours ( i2ctospi_t *ctx, i2ctospi_spi_t *spi )
{
    uint8_t ones;
    uint8_t tens;
    uint8_t result_hours;
    uint8_t temp;

    spi->slave_device = I2CTOSPI_SLAVEDEVICE_SS0;
    spi->function_id = I2CTOSPI_RTC5_COMMAND_READ;
    spi->reg_addr = I2CTOSPI_RTC5_REG_TIME_HOUR;

    temp = i2ctospi_spi_read_byte( ctx, spi );

    ones = temp & 0x0F;

    tens = ( temp & 0x30 ) >> 4;

    result_hours = ( 10 * tens ) + ones;

    return result_hours;
}

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    i2ctospi_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.

    i2ctospi_cfg_setup( &cfg );
    I2CTOSPI_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    i2ctospi_init( &i2ctospi, &cfg );

    i2ctospi_default_cfg( &i2ctospi );
    
    //Set Time :  23h 59m 48s
    rtc5_clear( &i2ctospi, &i2ctospi_spi );  
    rtc5_set_time_hours( &i2ctospi, &i2ctospi_spi, 23 );
    Delay_1ms( );
    rtc5_set_time_minutes( &i2ctospi, &i2ctospi_spi, 59 );
    Delay_1ms( );
    rtc5_set_time_seconds( &i2ctospi, &i2ctospi_spi, 48 );
    Delay_1ms( );
}

void application_task ( void )
{
    time_seconds = rtc5_get_time_seconds( &i2ctospi, &i2ctospi_spi );
    Delay_1ms( );
    time_minutes = rtc5_get_time_minutes( &i2ctospi, &i2ctospi_spi );
    Delay_1ms( );
    time_hours = rtc5_get_time_hours( &i2ctospi, &i2ctospi_spi );
    Delay_1ms( );

    if ( time_seconds_new != time_seconds )
    {
        log_printf( &logger, " Time :  " );
    
        display_log_uart( time_hours );
        log_printf( &logger, ":" );
    
        display_log_uart( time_minutes );
        log_printf( &logger, ":" );
    
        display_log_uart( time_seconds );
        log_printf( &logger, "\r\n" );
        
        log_printf( &logger, "------------------\r\n" );

        time_seconds_new = time_seconds;
    }

    Delay_1ms( );
}

void main ( void )
{
    application_init( );

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


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

Additional Support

Resources

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