Take your audio to new heights with LM4860 and PIC18F2455
Amplify every beat, enhance every note!
Published Nov 01, 2023
Click board™
AudioAmp 4 Click
Dev Board
EasyPIC v8
Compiler
NECTO Studio
MCU
PIC18F2455
Enhance your embedded solution's audio performance and invest in the future of audio technology with our advanced audio amplifier
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Hardware Overview
How does it work?
AudioAmp 4 Click is based on the LM4860, a Boomer® series 1W audio power amplifier with shutdown mode from Texas Instruments. Besides the LM4860, there is also the CD74HC4051, a high-speed CMOS logic analog mux/demux IC from Texas Instruments. The LM4860 is used as the main audio amplifier component. This IC features a high level of integration, reducing the number of external components to a minimum. It does not require any output capacitors, bootstrap capacitors, or snubber circuits, which makes the design straightforward. Besides other functions, the IC features the Shutdown mode, activated by a HIGH logic level on a dedicated SHUTDOWN pin. Therefore, this pin must be set to a LOW logic level to enable the amplifier. However, AudioAmp 4 click already has a pull-down resistor, so the audio amplifier IC is enabled by default. The SHUTDOWN pin is routed to the CS pin of the mikroBUS™, labeled as EN. While in Shutdown mode, the power consumption is minimized, which is very useful for applications that rely on a battery power supply. The Shutdown mode pin is also routed to the
#E pin of the CD74HC4051, simultaneously disabling this IC as well. The audio signal can be connected via the 3.5mm JACK connector. By default, this signal is connected to one side of the voltage divider, composed of eight resistors. The other end of the voltage divider is tied to the GND, while the middle tap of the voltage divider can be selected by activating any of the eight available positions of the CD74HC4051 IC. The CD74HC4051 IC uses three control pins, allowing its internal analog SP8T switch to be closed between any of the eight I/O pins (A0 to A7) and one common I/O pin. The audio signal goes through this divider, gets divided by the ratio selected with the control pins, and into the audio input of the LM4860 audio amp IC. This results in having eight discrete volume levels, which can be digitally selected by S0-S3 control pins routed to the mikroBUS™. AudioAmp 4 Click is equipped with the SMD jumper labeled IN SEL. This jumper allows to selection the output from the RC filter, which filters out the PWM signal from the mikroBUS™ PWM pin, creating a DC signal of constant voltage.
By changing the PWM signal's pulse width, the RC filter's voltage output will change. If the IN SEL switch is moved to the PWM position, this signal will be introduced into the voltage divider instead of the 3.5mm jack connector audio signal. It can be used to generate custom waveforms by the software running on the host MCU. Three control pins of the CD74HC4051, labeled as S0, S1, and S2, are routed to the mikroBUS™ pins AN, RST, and INT, respectively, labeled according to the names of the control pins. These pins accept logic HIGH and LOW levels from the host MCU, so the CD74HC4051 can be controlled using a binary format on the control pins. The Click board™ uses only 5V rail from the mikroBUS™, so it should not be interfaced with MCUs with only 3.3V tolerant pins. The complete control of the IC is done exclusively by the GPIO pins of the MCU, so the software development complexity is reduced to a minimum. However, the click comes with the mikroSDK compliant library, offering a simple usage example and functions for rapidly developing applications.
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)
24
Silicon Vendor
Microchip
Pin count
28
RAM (Bytes)
2048
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the EasyPIC v8 as your development board.
Track your results in real time
Application Output via UART Mode
1. Once the code example is loaded, pressing the "FLASH" button initiates the build process, and programs it on the created setup.
2. After the programming is completed, click on the Tools icon in the upper-right panel, and select the UART Terminal.
3. After opening the UART Terminal tab, first check the baud rate setting in the Options menu (default is 115200). If this parameter is correct, activate the terminal by clicking the "CONNECT" button.
4. Now terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.
Software Support
Library Description
This library contains API for AudioAmp 4 Click driver.
Key functions:
audioamp4_set_channel- This function sets the volume channel.audioamp4_shutdown- This function is used to switch device ON or OFF
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 AudioAmp 4 Click example
*
* # Description
* This example switches device on & off and sets volume channel to 3.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes GPIO interface, turns module ON and sets volume level to 0.
*
* ## Application Task
* Turns device OFF & ON and sets a three different volume values.
*
* ## Additional Functions
* - application_error_handler - Collects the response from the functions.
*
* \author Petar Suknjaja
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "audioamp4.h"
// ------------------------------------------------------------------ VARIABLES
static audioamp4_t audioamp4;
static log_t logger;
// ------------------------------------------------------- ADDITIONAL FUNCTIONS
void application_error_handler ( AUDIOAMP4_RETVAL error_code )
{
switch ( error_code )
{
case AUDIOAMP4_OK :
{
log_info( &logger, "OK\r\n");
break;
}
case AUDIOAMP4_SHTDWN_STATE_ERR :
{
log_info( &logger, "Shutdown state error\r\n" );
break;
}
case AUDIOAMP4_VOL_CHANN_ERR :
{
log_info( &logger, "Volume channel error\r\n" );
break;
}
default :
{
break;
}
}
}
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
audioamp4_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.
audioamp4_cfg_setup( &cfg );
AUDIOAMP4_MAP_MIKROBUS( cfg, MIKROBUS_1 );
audioamp4_init( &audioamp4, &cfg );
audioamp4_default_cfg( &audioamp4 );
}
void application_task ( void )
{
log_info( &logger, "Turn on device:" );
application_error_handler( audioamp4_shutdown( &audioamp4, AUDIOAMP4_SHUTDOWN_OFF ) );
log_info( &logger, "Set volume channel 1:" );
application_error_handler( audioamp4_set_channel( &audioamp4, AUDIOAMP4_VOLUME_CHANN_1 ) );
Delay_ms( 2000 );
log_info( &logger, "Set volume channel 5:" );
application_error_handler( audioamp4_set_channel( &audioamp4, AUDIOAMP4_VOLUME_CHANN_5 ) );
Delay_ms( 2000 );
log_info( &logger, "Set volume channel 7:" );
application_error_handler( audioamp4_set_channel( &audioamp4, AUDIOAMP4_VOLUME_CHANN_7 ) );
Delay_ms( 2000 );
log_info( &logger, "Turn off device:" );
application_error_handler( audioamp4_shutdown( &audioamp4, AUDIOAMP4_SHUTDOWN_ON ) );
Delay_ms( 500 );
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
