Intermediate
30 min

Unlock data-driven decisions with precise weight measurements using AD7780 and PIC32MZ2048EFH100

Weight matters, accuracy counts

Load Cell 5 Click with Flip&Click PIC32MZ

Published Aug 29, 2023

Click board™

Load Cell 5 Click

Dev. board

Flip&Click PIC32MZ

Compiler

NECTO Studio

MCU

PIC32MZ2048EFH100

Achieve your health goals with accurate weight tracking for personalized progress

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Hardware Overview

How does it work?

Load Cell 5 Click is based on the AD7780, a pin programmable, low power, low drift 24-bit ΣΔ ADC from Analog Devices that includes a PGA and uses an internal clock. The AD7780 typically consumes only 330μA and simplifies this weigh scale design since most of the system building blocks are already on the chip. The AD7780 has two filter options selectable via FIL pin(low state - 16.7Hz, high state - 10Hz) and a Power-Down Mode, allowing the user to switch off the power to the bridge sensor and power down the AD7780 when not converting, increasing the battery life. Since the AD7780 provides an integrated solution for weighing scales, it interfaces directly with the load cell. The only required external components, which are also on the Click board™, are filters on the analog inputs and capacitors on the reference pins for EMC purposes. The low-level signal from the load cell is amplified by the AD7780's internal PGA programmed via the PWM pin of the mikroBUS™ socket, labeled as GN, to operate with

a gain of 128 or 1. The conversions from the AD7780 are then sent to the MCU through the SPI serial interface, where the digital information is converted to weight. This Click board™ uses the 6-wire load cell configuration, which has two sense pins, ground, power supply, and two output connections. The load cell differential SENSE lines connected to the AD7780 reference inputs create a ratiometric configuration immune to low-frequency changes in the power supply excitation voltage. Those sense pins are connected to the high and low sides of the Wheatstone bridge, where voltage can be accurately measured, regardless of the voltage drop due to the wiring resistance. The AD7780 has separate analog and digital power supply pins. The analog and digital power supplies are independent of each other to be different, or the same, potentials achieved with the AVDD SEL jumper. This feature allows selecting the AD7780 power supply between an external power supply (2.7 - 5.25V) and logic

voltage levels supplied via mikroBUS™ rails. Load Cell 5 Click communicates with MCU using a standard SPI interface with a dual-purpose DOUT/RDY line. This line can function as a regular data output pin for the SPI interface or as a data-ready pin (interrupt) labeled as RDY and routed on the INT pin of the mikroBUS socket. Also, it uses the RST pin on the mikroBUS™ socket, which performs the Hardware Reset function by putting this pin in a logic low state, and a blue diode labeled as ACTIVE is used to indicate the device's Active Operational Status. 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.

Load Cell 5 Click hardware overview image

Features overview

Development board

Flip&Click PIC32MZ is a compact development board designed as a complete solution 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, the PIC32MZ2048EFH100 from Microchip, four mikroBUS™ sockets for Click board™ connectivity, two USB connectors, LED indicators, buttons, debugger/programmer connectors, and two headers compatible with Arduino-UNO pinout. Thanks to innovative manufacturing technology,

it allows you to build gadgets with unique functionalities and features quickly. Each part of the Flip&Click PIC32MZ development kit contains the components necessary for the most efficient operation of the same board. In addition, there is the possibility of choosing the Flip&Click PIC32MZ programming method, using the chipKIT bootloader (Arduino-style development environment) or our USB HID bootloader using mikroC, mikroBasic, and mikroPascal for PIC32. This kit includes a clean and regulated power supply block through the USB Type-C (USB-C) connector. All communication

methods that mikroBUS™ itself supports are on this board, including the well-established mikroBUS™ socket, user-configurable buttons, and LED indicators. Flip&Click PIC32MZ development kit allows 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.

Flip&Click PIC32MZ double image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC32

MCU Memory (KB)

2048

Silicon Vendor

Microchip

Pin count

100

RAM (Bytes)

524288

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset
RE2
RST
Filter Selection
RA0
CS
SPI Clock
RG6
SCK
SPI Data OUT
RC4
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Gain Selection
RC14
PWM
Interrupt / Data Ready
RD9
INT
NC
NC
TX
NC
NC
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

Load Cell 5 Click Schematic schematic

Step by step

Project assembly

Flip&Click PIC32MZ front image hardware assembly

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

Flip&Click PIC32MZ front image hardware assembly
GNSS2 Click front image hardware assembly
Prog-cut hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
Flip&Click PIC32MZ MB1 Access - 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

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 Load Cell 5 Click driver.

Key functions:

  • loadcell5_set_power_mode - Load Cell 5 set power mode function

  • loadcell5_read_adc - Load Cell 5 reading ADC data function

  • loadcell5_get_weight - Load Cell 5 get weight 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 LoadCell5 Click example
 *
 * # Description
 * This library contains API for Load Cell 5 Click driver.
 * The library initializes and defines the SPI bus drivers to read status and ADC data. 
 * The library also includes a function for tare, calibration and weight measurement.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * The initialization of SPI module, log UART, and additional pins
 * and performs the power on. Sets tare the scale, calibrate scale 
 * and start measurements. 
 *
 * ## Application Task
 * This is an example that demonstrates the use of the Load Cell 5 click board.
 * The Load Cell 5 click board can be used to measure weight,
 * shows the measurement of scales in grams [ g ].
 * Results are being sent to the Usart Terminal where you can track their changes.
 *
 * @author Nenad Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "loadcell5.h"

static loadcell5_t loadcell5;
static log_t logger;

static uint8_t status_val;
static uint32_t adc_val;

static loadcell5_data_t cell_data;
static float weight_val;

void application_init ( void ) {
    log_cfg_t log_cfg;  /**< Logger config object. */
    loadcell5_cfg_t loadcell5_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.

    loadcell5_cfg_setup( &loadcell5_cfg );
    LOADCELL5_MAP_MIKROBUS( loadcell5_cfg, MIKROBUS_1 );
    err_t init_flag  = loadcell5_init( &loadcell5, &loadcell5_cfg );
    if ( init_flag == SPI_MASTER_ERROR ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }

    loadcell5_default_cfg ( &loadcell5 );
    log_info( &logger, " Application Task " );
    Delay_ms( 500 ); 
    
    log_printf( &logger, "-------------------------\r\n");
    log_printf( &logger, "     Tare the scale :    \r\n");
    log_printf( &logger, "- - - - - - - - - - - - -\r\n");
    log_printf( &logger, " >> Remove all object << \r\n");
    log_printf( &logger, "- - - - - - - - - - - - -\r\n");
    log_printf( &logger, " In the following 10 sec \r\n");
    log_printf( &logger, " please remove all object\r\n");
    log_printf( &logger, "     from the scale.     \r\n");
    Delay_ms( 10000 );

    log_printf( &logger, "-------------------------\r\n");
    log_printf( &logger, "    Start tare scales    \r\n");
    loadcell5_tare ( &loadcell5, &cell_data );
    Delay_ms( 500 );

    log_printf( &logger, "-------------------------\r\n");
    log_printf( &logger, "   Tarring is complete   \r\n");
    log_printf( &logger, "-------------------------\r\n");
    log_printf( &logger, "    Calibrate Scale :    \r\n");
    log_printf( &logger, "- - - - - - - - - - - - -\r\n");
    log_printf( &logger, "   >>> Load etalon <<<   \r\n");
    log_printf( &logger, "- - - - - - - - - - - - -\r\n");
    log_printf( &logger, " In the following 10 sec \r\n");
    log_printf( &logger, "place 100g weight etalon\r\n");
    log_printf( &logger, "    on the scale for     \r\n");
    log_printf( &logger, "   calibration purpose.  \r\n");
    Delay_ms( 10000 );

    log_printf( &logger, "-------------------------\r\n");
    log_printf( &logger, "    Start calibration    \r\n");

    if ( loadcell5_calibration ( &loadcell5, LOADCELL5_WEIGHT_100G, &cell_data ) == LOADCELL5_OK ) {
        log_printf( &logger, "-------------------------\r\n");
        log_printf( &logger, "    Calibration  Done    \r\n");

        log_printf( &logger, "- - - - - - - - - - - - -\r\n");
        log_printf( &logger, "  >>> Remove etalon <<<  \r\n");
        log_printf( &logger, "- - - - - - - - - - - - -\r\n");
        log_printf( &logger, " In the following 10 sec \r\n");
        log_printf( &logger, "   remove 100g weight   \r\n");
        log_printf( &logger, "   etalon on the scale.  \r\n");
        Delay_ms( 10000 );
    }
    else {
        log_printf( &logger, "-------------------------\r\n");
        log_printf( &logger, "   Calibration  Error   \r\n");
        for ( ; ; );
    }

    log_printf( &logger, "-------------------------\r\n");
    log_printf( &logger, "   Start measurements :  \r\n");
    log_printf( &logger, "-------------------------\r\n");
}

void application_task ( void ) {   
    weight_val = loadcell5_get_weight( &loadcell5, &cell_data );

    log_printf(&logger, "   Weight : %.2f g\r\n", weight_val );

    Delay_ms( 1000 );
}

void main ( void ) {
    application_init( );

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

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

Additional Support

Resources

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