Build a reliable timing system with MIC1557 and PIC18LF46K80

Make sure your circuits are never out of tune

Published Nov 01, 2023

Click board™

Clock Gen 6 Click

Dev. board

EasyPIC v8

Compiler

NECTO Studio

MCU

PIC18LF46K80

IttyBitty CMOS RC oscillator designed to provide rail-to-rail pulses for precise time delay or frequency generation

Hardware Overview

How does it work?

Clock Gen 6 Click is based on the MIC1557, a low-power digital frequency solution providing the logic for creating a simple RC oscillator circuit from Microchip Technology. The MIC1557 offers rail-to-rail pulses for precise frequency generation alongside a single threshold and trigger connection, internally connected, for astable (oscillator) operation only with programmable output frequency and enable/reset control signal intended as an oscillator with a Shutdown capability. As mentioned, the astable oscillator switches between two states, ON and OFF, producing a continuous square wave. The MIC1557 is optimized for this function by tying the two comparator inputs together, the threshold, and trigger pins (THR and TRG), forming a T/T pin.

The external capacitor charges slowly through the external resistor in the form of a digital potentiometer by which the user can pass through the frequency range and thus adjust the desired output. Replacing the resistor with a digital potentiometer allows the user to program frequency output as performed on this Click board™. For this purpose, the digital potentiometer MAX5401, which communicates with the MCU via a 3-Wire SPI serial interface, is used to set the resistance on the MIC1557 OUT line, adjusting the frequency up to 5MHz. Alongside SPI communication, this Click board™ also uses one additional pin. The Enable pin, labeled as EN and routed to the RST pin of the mikroBUS™ socket, optimizes power consumption and is used for power ON/OFF purposes

(controls the bias supply to the oscillator’s internal circuitry). When the MIC1557 is deselected, the supply current is less than 1μA, and the device is placed in a Shutdown state. Forcing the EN pin low resets the device by setting the flip flop, causing the output to a low logic state. 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. However, the 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

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

Enable

RE1

RST

SPI Chip Select

RE0

SPI Clock

RC3

SCK

SPI Data OUT

RC4

MISO

SPI Data IN

RC5

MOSI

Power Supply

3.3V

Ground

GND

PWM

INT

SCL

SDA

Power Supply

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

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 Clock Gen 6 Click driver.

Key functions:

clockgen6_set_digipot This function sets the digital potentiometer position by using SPI serial interface.
clockgen6_enable_output This function enables the output by setting the EN pin to high logic state.
clockgen6_disable_output This function disables the output by setting the EN pin to low logic state.

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 Clock Gen 6 Click Example.
 *
 * # Description
 * This example demonstrates the use of Clock Gen 6 click board which acts as 
 * an astable oscillator.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and performs the click default configuration which sets the digital
 * potentiometer to max position and enables the clock output.
 *
 * ## Application Task
 * Changes the clock output frequency by changing the digital potentiometer position every second.
 * The potentiometer position value will be displayed on the USB UART.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "clockgen6.h"

static clockgen6_t clockgen6;   /**< Clock Gen 6 Click driver object. */
static log_t logger;    /**< Logger object. */

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    clockgen6_cfg_t clockgen6_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.
    clockgen6_cfg_setup( &clockgen6_cfg );
    CLOCKGEN6_MAP_MIKROBUS( clockgen6_cfg, MIKROBUS_1 );
    if ( DIGITAL_OUT_UNSUPPORTED_PIN == clockgen6_init( &clockgen6, &clockgen6_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( CLOCKGEN6_ERROR == clockgen6_default_cfg ( &clockgen6 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    for ( int16_t pos = CLOCKGEN6_DIGIPOT_POSITION_MAX; pos >= CLOCKGEN6_DIGIPOT_POSITION_MIN; )
    {
        if ( CLOCKGEN6_OK == clockgen6_set_digipot ( &clockgen6, pos ) )
        {
            log_printf( &logger, " DIGIPOT position: %u\r\n", pos );
            Delay_ms ( 1000 );
            pos -= 5;
        }
    }
}

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

/*!
 * @file main.c
 * @brief Clock Gen 6 Click Example.
 *
 * # Description
 * This example demonstrates the use of Clock Gen 6 click board which acts as 
 * an astable oscillator.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and performs the click default configuration which sets the digital
 * potentiometer to max position and enables the clock output.
 *
 * ## Application Task
 * Changes the clock output frequency by changing the digital potentiometer position every second.
 * The potentiometer position value will be displayed on the USB UART.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "clockgen6.h"

static clockgen6_t clockgen6;   /**< Clock Gen 6 Click driver object. */
static log_t logger;    /**< Logger object. */

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    clockgen6_cfg_t clockgen6_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.
    clockgen6_cfg_setup( &clockgen6_cfg );
    CLOCKGEN6_MAP_MIKROBUS( clockgen6_cfg, MIKROBUS_1 );
    if ( DIGITAL_OUT_UNSUPPORTED_PIN == clockgen6_init( &clockgen6, &clockgen6_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( CLOCKGEN6_ERROR == clockgen6_default_cfg ( &clockgen6 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    for ( int16_t pos = CLOCKGEN6_DIGIPOT_POSITION_MAX; pos >= CLOCKGEN6_DIGIPOT_POSITION_MIN; )
    {
        if ( CLOCKGEN6_OK == clockgen6_set_digipot ( &clockgen6, pos ) )
        {
            log_printf( &logger, " DIGIPOT position: %u\r\n", pos );
            Delay_ms ( 1000 );
            pos -= 5;
        }
    }
}

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

/*!
 * @file main.c
 * @brief Clock Gen 6 Click Example.
 *
 * # Description
 * This example demonstrates the use of Clock Gen 6 click board which acts as 
 * an astable oscillator.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and performs the click default configuration which sets the digital
 * potentiometer to max position and enables the clock output.
 *
 * ## Application Task
 * Changes the clock output frequency by changing the digital potentiometer position every second.
 * The potentiometer position value will be displayed on the USB UART.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "clockgen6.h"

static clockgen6_t clockgen6;   /**< Clock Gen 6 Click driver object. */
static log_t logger;    /**< Logger object. */

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    clockgen6_cfg_t clockgen6_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.
    clockgen6_cfg_setup( &clockgen6_cfg );
    CLOCKGEN6_MAP_MIKROBUS( clockgen6_cfg, MIKROBUS_1 );
    if ( DIGITAL_OUT_UNSUPPORTED_PIN == clockgen6_init( &clockgen6, &clockgen6_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( CLOCKGEN6_ERROR == clockgen6_default_cfg ( &clockgen6 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    for ( int16_t pos = CLOCKGEN6_DIGIPOT_POSITION_MAX; pos >= CLOCKGEN6_DIGIPOT_POSITION_MIN; )
    {
        if ( CLOCKGEN6_OK == clockgen6_set_digipot ( &clockgen6, pos ) )
        {
            log_printf( &logger, " DIGIPOT position: %u\r\n", pos );
            Delay_ms ( 1000 );
            pos -= 5;
        }
    }
}

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