Upgrade your video experience with MAX7456 and PIC18F47K42TQFP
Display various characters and symbols to your videos, anywhere, anytime!
Published Feb 13, 2024
Click board™
OSD Click
Development board
Curiosity Nano with PIC18F47K42
Compiler
NECTO Studio
MCU
PIC18F47K42TQFP
Add a monochrome on-screen display overlay to video applications without requiring external drivers
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Hardware Overview
How does it work?
OSD Click is based on the MAX7456, a single-channel monochrome on-screen display generator from Maxim Integrated. This Click board™ accepts composite NTSC or PAL signals and inserts a user-defined OSD as a layer over the video. The MAX7456 includes an input clamp, sync separator, video timing generator, OSD insertion MUX, nonvolatile character memory, display memory, OSD generator, and more. As the user-defined 256 (12 x 18 pixel) character set comes preloaded, combined with a video stream, the Click board™ generates a CVBS signal. The operating mode depends on the number of displayed rows, whereas for NTSC, it is 13 rows x 30 chars, and for PAL, it is 16 rows x 30 chars. This Click board™
communicates with the host MCU through a standard SPI serial interface of the mikroBUS™ socket. The MAX7456 provides vertical, horizontal, and loss of sync signals for system synchronizations. These synchronizations are essential for the OSD layer to stay in place. The vertical synchronization feature is accessed through a VS line routed to the INT of the mikroBUS™ socket, while the horizontal sync is accessed through the HS line routed to the PWM pin of the mikroBUS™ socket. Loss of synchronization signal, marked as LOS and routed to the mikroBUS™ AN pin, will go to a low logic state when 32 consecutive, valid sync pulses are received, otherwise will go high. OSD Click also
possesses a general reset feature accessed with the RST pin of the mikroBUS™ socket. This Click board™ also has two RCA connectors labeled IN and OUT for connecting input and output video signals. Coupling capacitors are also populated on the video connection lines for guaranteed specified line time (LTD) and video clamp setting time. This Click board™ can only be operated with a 5V logic voltage level. This Click board™ can be operated only with a 5V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it comes equipped with a library containing functions and an example code that can be used as a reference for further development.
Features overview
Development board
PIC18F47K42 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate the PIC18F47K42 microcontroller (MCU). Central to its design is the inclusion of the powerful PIC18F47K42 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 2.3V to 5.1V (limited by USB input voltage), with a maximum output current of 500mA, subject to ambient temperature and voltage constraints.
Microcontroller Overview
MCU Card / MCU
Architecture
PIC
MCU Memory (KB)
128
Silicon Vendor
Microchip
Pin count
40
RAM (Bytes)
8192
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.
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 Curiosity Nano with PIC18F47K42 as your development board.
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.
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™.
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.
Software Support
Library Description
This library contains API for OSD Click driver.
Key functions:
osd_clear_display_memory- This function clears display memoryosd_insert_custom_char- This function writes custom characterosd_enable_video_buffer- This function enables video buffer
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 OSD Click example
*
* # Description
* This demo performs basic OSD Click functionality - write text on screen.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initialize device.
*
* ## Application Task
* Write text on the screen, write character per 1 second
* in the first, seventh and fifteenth row of the screen.
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "osd.h"
// ------------------------------------------------------------------ VARIABLES
static osd_t osd;
static log_t logger;
const uint8_t HEADER_TEXT[ 30 ] =
{
' ', ' ', 'O', 'S', 'D', ' ', 'c', 'l', 'i', 'c', 'k', ' ', ' ', ' ', ' ', ' ',
' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' '
};
const uint8_t MESSAGE_TEXT[ 30 ] =
{
' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', 'm', 'i', 'k', 'r',
'o', 'E', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' '
};
const uint8_t FOOTER_TEXT[ 30 ] =
{
' ', 'w', 'w', 'w', '.', 'm', 'i', 'k', 'r', 'o', 'e', '.', 'c', 'o', 'm', ' ',
' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' '
};
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
osd_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.
osd_cfg_setup( &cfg );
OSD_MAP_MIKROBUS( cfg, MIKROBUS_1 );
osd_init( &osd, &cfg );
osd_default_cfg( &osd );
osd_clears_char_places( &osd, 0, 0, 16, 30 );
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
log_printf( &logger, "\r\n Writing characters on the screen...\r\n" );
for ( uint8_t cnt = 0; cnt < 30; cnt++ )
{
if ( HEADER_TEXT[ cnt ] != ' ' )
{
osd_write_character( &osd, 1, cnt, HEADER_TEXT[ cnt ] );
}
if ( MESSAGE_TEXT[ cnt ] != ' ' )
{
osd_write_character( &osd, 7, cnt, MESSAGE_TEXT[ cnt ] );
}
if ( FOOTER_TEXT[ cnt ] != ' ' )
{
osd_write_character( &osd, 14, cnt, FOOTER_TEXT[ cnt ] );
}
Delay_ms( 1000 );
}
log_printf( &logger, " Clear display\r\n" );
osd_clears_char_places( &osd, 0, 0, 16, 30 );
Delay_ms( 3000 );
}
int main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
return 0;
}
// ------------------------------------------------------------------------ END
