Intermediate
30 min
0

Experience cutting-edge mixed-signal conversions with MAX11300 and PIC18F26K22

PIXI - Programmable mIXed signal In/out

PIXI Click with EasyPIC v7a

Published Nov 01, 2023

Click board™

PIXI Click

Development board

EasyPIC v7a

Compiler

NECTO Studio

MCU

PIC18F26K22

With its 20-channel capability and versatile PIXI™ technology, our solution empowers engineers to create complex systems that demand high-performance mixed-signal data conversion

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Hardware Overview

How does it work?

PIXI Click is based on the MAX11300 from Analog Devices. The main feature of this IC is the proprietary PIXI™ technology. PIXI™ is an abbreviation for the Programmable mIXed signal In/Out, a technology that allows very flexible routing of both digital and analog signals. The MAX11300 IC has 20 configurable mixed-signal I/O ports. Each port can be independently configured as a DAC output, an ADC input, a GPI, a GPO, or an analog switch terminal. User-controllable parameters are available for each of those configurations. The device also features internal and external temperature sensors with ±1˚C accuracy. The device uses the SPI Mode 0 interface for communication with the controller, with the clock up to 20MHz. The MAX11300 device features a 12-bit successive approximation (SAR) ADC module, which can sample signals on a single port up to 400Ksmp/S. Like all the segments of this device, it also offers great flexibility; the signal can be unipolar or bipolar. Each ADC-configured port can be programmed for one of four input

voltage ranges: 0V to +10V, -5V to +5V, -10V to 0V, and 0V to +2.5V. There are two inputs for the reference voltage, but the internal reference voltage of 2.5V can also be used instead. The CNVT# pin can trigger the converter, routed to the PWM pin of the mikroBUS™. This pin has to stay in the LOW logic state for at least 0.5 µs to trigger the conversion. There are several conversion modes, including sampling on a single port or sweeping through all the configured ADC ports. ADC offers the averaging feature, too. It can average readings of the ADC-configured ports to blocks of 2, 4, 8, 16, 32, 64, or 128 conversion results. The buffered DAC converter is also 12-bit, which can output up to 25Ksmp/s on a single port. The output stage of the DAC is equipped with the driver, which offers ±10V on output and high current capability, using the dedicated power supplies (AVDDIO, AVSSIO pins of the PIXI™ header). The DAC module also uses internal or external reference voltage. The flexibility of the PIXI™ routing also allows monitoring of the DAC-configured ports

by utilizing the ADC module. All the DAC ports are protected from overcurrent, and such events can generate an interrupt on the INT pin, routed to the INT# pin on the mikroBUS™. Each of the PIXI™ ports can be configured as the general purpose input or general purpose output pin (GPI/GPO). When set as the GPI pin, the programmable threshold can be set by its data register from 0 to the AVDD voltage. The events like rising edges, falling edges, or both can be sensed this way, generating an interrupt. A GPO pin can have a programmed HIGH logic level, up to four times the DAC referent voltage. The host can set the logic state of GPO-configured ports through the corresponding GPO data registers. Combining GPI and GPO-configured ports allows unidirectional and bidirectional level translator paths to be formed, allowing all kinds of level shifters to be built. Bidirectional level translators are built using adjacent pairs of pins and are meant to work as the open drain drivers, so the pull-up resistors should be used to achieve proper voltage levels.

pixi-click-hardware-overview

Features overview

Development board

EasyPIC v7a is the seventh generation of PIC development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 8-bit PIC microcontrollers from Microchip and has a broad set of unique functions, such as the first-ever embedded debugger/programmer over USB-C. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyPIC v7a allows you to connect accessory boards, sensors, and custom electronics more efficiently than ever. Each part of the EasyPIC v7a 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 various external power sources, including an external 12V power supply, 7-23V AC or 9-32V DC via DC connector/screw terminals, and a power source via the USB Type-C (USB-C) connector. Communication options such as USB-UART and RS-232 are also included, alongside the well-

established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 8-bit PIC MCUs, from PIC10F, PIC12F, PIC16F, PIC16Enh, PIC18F, PIC18FJ, and PIC18FK families. EasyPIC v7a 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.

EasyPIC v7a double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

64

Silicon Vendor

Microchip

Pin count

28

RAM (Bytes)

3896

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
SPI Chip Select
RA5
CS
SPI Clock
RC3
SCK
SPI Data OUT
RC4
MISO
SPI Data IN
RC5
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
ADC Trigger Control
RC1
PWM
Interrupt
RB1
INT
NC
NC
TX
NC
NC
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
2

Take a closer look

Schematic

PIXI Click Schematic schematic

Step by step

Project assembly

EasyPIC v7a front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v7a as your development board.

EasyPIC v7a front image hardware assembly
LTE IoT 5 Click front image hardware assembly
MCU DIP 28 hardware assembly
LTE IoT 5 Click complete accessories setup image hardware assembly
EasyPIC v7a Access MB 2 - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
NECTO Compiler Selection Step Image hardware assembly
NECTO Output Selection Step Image hardware assembly
Necto image step 6 hardware assembly
Necto DIP image step 7 hardware assembly
EasyPIC PRO v7a Display Selection Necto Step hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto PreFlash Image hardware assembly

Track your results in real time

Application Output

After pressing the "FLASH" button on the left-side panel, it is necessary to open the UART terminal to display the achieved results. By clicking on the Tools icon in the right-hand panel, multiple different functions are displayed, among which is the UART Terminal. Click on the offered "UART Terminal" icon.

UART Application Output Step 1

Once the UART terminal is opened, the window takes on a new form. At the top of the tab are two buttons, one for adjusting the parameters of the UART terminal and the other for connecting the UART terminal. The tab's lower part is reserved for displaying the achieved results. Before connecting, the terminal has a Disconnected status, indicating that the terminal is not yet active. Before connecting, it is necessary to check the set parameters of the UART terminal. Click on the "OPTIONS" button.

UART Application Output Step 2

In the newly opened UART Terminal Options field, we check if the terminal settings are correct, such as the set port and the Baud rate of UART communication. If the data is not displayed properly, it is possible that the Baud rate value is not set correctly and needs to be adjusted to 115200. If all the parameters are set correctly, click on "CONFIGURE".

UART Application Output Step 3

The next step is to click on the "CONNECT" button, after which the terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.

UART Application Output Step 4

Software Support

Library Description

This library contains API for PIXI Click driver.

Key functions:

  • pixi_write_reg - Generic write function

  • pixi_read_reg - Generic read function

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 Pixi Click example
 * 
 * # Description
 * This example showcases how to initialize, configure and use the Pixi click moduel. The click
 * features Maxim Integrated's versatile, proprietary PIXI™ technology - the industry's first
 * configurable 20-channel mixed-signal data converter. 
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * This function initializes and configures the click and logger modules. After the initial setup
 * a device id check is performed which will stop the module if the check fails. Additional con-
 * figurating is done in the default_cfg(...) function.
 * 
 * ## Application Task
 * This function sets the output signal on port 0 to different values every second. 
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "pixi.h"

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

static pixi_t pixi;
static log_t logger;

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

void application_init ( )
{
    log_cfg_t log_cfg;
    pixi_cfg_t cfg;
    uint32_t res;

    /** 
     * 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 ----" );
    Delay_ms( 100 );

    //  Click initialization.

    pixi_cfg_setup( &cfg );
    PIXI_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    pixi_init( &pixi, &cfg );

    //  Device ID check.

    pixi_read_reg( &pixi, PIXI_REG_DEVICE_ID, &res );
    if ( res != 1060 )
    {
        log_printf( &logger, "ERROR : WRONG DEVICE ID!\r\n" );
        for( ; ; );
    }
    else
    {
        log_printf( &logger, "Driver Init - DONE!\r\n" );
    }

    //  Default configuration.

    pixi_default_cfg( &pixi );
}

void application_task ( )
{
    pixi_write_reg( &pixi, PIXI_REG_GPO_DATA, 0x1 );
    log_printf( &logger, "Led on\r\n" );
    Delay_ms( 2000 );
    pixi_write_reg( &pixi, PIXI_REG_GPO_DATA, 0 );
    log_printf( &logger, "Led off\r\n" );
    Delay_ms( 2000 );
}

void main ( )
{
    application_init( );

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

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

Additional Support

Resources