Intermediate
30 min

Create precise time intervals with DS1087L and PIC18F57Q43

Accurate square wave generator

Clock Gen 2 Click with Curiosity Nano with PIC18F57Q43

Published Feb 13, 2024

Click board™

Clock Gen 2 Click

Dev Board

Curiosity Nano with PIC18F57Q43

Compiler

NECTO Studio

MCU

PIC18F57Q43

Elevate your engineering solution with a cutting-edge clock generator, delivering reliable and efficient timing signals

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Hardware Overview

How does it work?

Clock Gen 2 Click is based on the DS1087, a 3.3V spread-spectrum EconOscillator from Analog Devices. This IC is factory-produced with a range of different master clock frequencies, ranging from 33.3 MHz, up to 66.6 MHz, with variable spread spectrum percentages. The IC on the Clock Gen 2 click has the master clock fixed to 66.6 MHz, allowing the frequency range from 260 kHz to 66.6 MHz. This IC uses the clock prescaler from 2 0 to 2 8 to achieve frequencies different from the master frequency. By selecting the spread-spectrum percentage, it is possible to avoid the generation of too much EMI, which otherwise might violate the FCC/IEC regulations. As mentioned, the internal clock frequency that the DS1087 generates is 66.6MHz. The master clock is frequency-modulated by the internal triangle wave generator. The main oscillator frequency can be dithered below the maximum frequency by a selectable ratio. A bit in the prescaler register determines the spread-spectrum dither range, which can be selected between 2% and 4%

under the main clock frequency. The IC pin labeled as SPRD is routed to the mikroBUS™ PWM pin. A logic HIGH level on this pin enables the spread-spectrum function. The DS1087LU is equipped with non-volatile memory locations (EEPROM) to store the content of all the configuration registers. Writing data to the configuration registers can be automatically mirrored to the EEPROM. This is controlled by the Write Control bit (WC). It allows automatically storing data to EEPROM after each register change (WC = 0, default) or storing the config data manually by issuing the WRITE EE command (WC = 1). This feature allows the configuration to be remembered between the POR (Power ON Reset) cycles. The output Enable (OE) pin allows the output clock to be turned off at the output pin. A logic HIGH level on this pin turns off the clock output. However, this will not turn off the internal master clock generator, so the IC will still drain the power necessary to work. To completely put the device in a power-down mode, another pin is

used: a logic LOW level on the PDN pin shuts down the master oscillator, draining less current from the power source. The OE pin is routed to the mikroBUS™ CS pin and is labeled as OE, while the PDN pin is routed to the RST pin of the mikroBUS™ and is labeled as PDN. These signals are synchronized with the internal master clock, preventing glitches at the output. The clock output signal is at the SMA connector on the Click board™. This connector protects the high-frequency clock signal and further reduces EMI. It also provides reliable contact with the least possible losses. The clock output signal amplitude is 2.4V, which makes this Click board™ usable with most 3.3V operated MCUs and other devices. The standardized I2C interface allows this Click board™ to be interfaced with a wide range of devices. I2C clock and data pins of the IC (SCL and SDA) are routed to the appropriate mikroBUS™ pins, allowing simple and reliable interfacing.

Clock Gen 2 Click top side image
Clock Gen 2 Click bottom side image

Features overview

Development board

PIC18F57Q43 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate microcontrollers within the PIC18-Q43 family. Central to its design is the inclusion of the powerful PIC18F57Q43 microcontroller (MCU), offering advanced functionalities and robust performance. Key features of this evaluation kit include a yellow user LED and a responsive

mechanical user switch, providing seamless interaction and testing. The provision for a 32.768kHz crystal footprint ensures precision timing capabilities. With an onboard debugger boasting a green power and status LED, programming and debugging become intuitive and efficient. Further enhancing its utility is the Virtual serial port (CDC) and a debug GPIO channel (DGI

GPIO), offering extensive connectivity options. Powered via USB, this kit boasts an adjustable target voltage feature facilitated by the MIC5353 LDO regulator, ensuring stable operation with an output voltage ranging from 1.8V to 5.1V, with a maximum output current of 500mA, subject to ambient temperature and voltage constraints.

PIC18F57Q43 Curiosity Nano double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

48

RAM (Bytes)

8196

You complete me!

Accessories

Curiosity Nano Base for Click boards is a versatile hardware extension platform created to streamline the integration between Curiosity Nano kits and extension boards, tailored explicitly for the mikroBUS™-standardized Click boards and Xplained Pro extension boards. This innovative base board (shield) offers seamless connectivity and expansion possibilities, simplifying experimentation and development. Key features include USB power compatibility from the Curiosity Nano kit, alongside an alternative external power input option for enhanced flexibility. The onboard Li-Ion/LiPo charger and management circuit ensure smooth operation for battery-powered applications, simplifying usage and management. Moreover, the base incorporates a fixed 3.3V PSU dedicated to target and mikroBUS™ power rails, alongside a fixed 5.0V boost converter catering to 5V power rails of mikroBUS™ sockets, providing stable power delivery for various connected devices.

Curiosity Nano Base for Click boards accessories 1 image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Power Down
PA7
RST
Output Enable
PD4
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Dither Enable
PB0
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PB1
SCL
I2C Data
PB2
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Schematic

Clock Gen 2 Click Schematic schematic

Step by step

Project assembly

Curiosity Nano Base for Click boards front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity Nano with PIC18F57Q43 as your development board.

Curiosity Nano Base for Click boards front image hardware assembly
Charger 27 Click front image hardware assembly
PIC18F47Q10 Curiosity Nano front image hardware assembly
Prog-cut hardware assembly
Charger 27 Click complete accessories setup image hardware assembly
Curiosity Nano with PICXXX Access MB 1 - 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
PIC18F57Q43 Curiosity 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

After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.

Application Output Step 1

After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.

Application Output Step 3

Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.

Application Output Step 4

Software Support

Library Description

This library contains API for Clock Gen 2 Click driver.

Key functions:

  • clockgen2_output_enable - Function for enabling/disabling of the clock output

  • clockgen2_auto_setting_preserve - Function used for enabling/disabling auto settings preservation

  • clockgen2_set_prescaler - Function for setting the main clock prescaler

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 ClockGen2 Click example
 * 
 * # Description
 * This application enables generation of square waved clock signal in range from 260 kHz to 66,6 MHz
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Driver initialization.
 * 
 * ## Application Task  
 * Changes the prescaler and enables/disables the clock output.
 * 
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "clockgen2.h"

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

static clockgen2_t clockgen2;
static log_t logger;

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

void application_init ( void )
{
    log_cfg_t log_cfg;
    clockgen2_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.

    clockgen2_cfg_setup( &cfg );
    CLOCKGEN2_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    clockgen2_init( &clockgen2, &cfg );

    Delay_ms(100);
}

void application_task ( void )
{
    //  Task implementation.

    char i;
     
     for ( i = 5; i< 8; i++ )
     {
       clockgen2_set_prescaler( &clockgen2, i );
       clockgen2_output_enable( &clockgen2, 1 );
       Delay_ms( 2000 );

       clockgen2_output_enable( &clockgen2, 0 );
       Delay_ms( 2000 );
     }
}

void main ( void )
{
    application_init( );

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


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

Additional Support

Resources