ISM TX Click

How does it work?

ISM TX Click is based on the MAX41460, a UHF sub-GHz ISM/SRD transmitter designed to transmit On-Off Keying (OOK), Amplitude- Shift Keying (ASK), Frequency-Shift Keying (FSK), and Gaussian (G)FSK (or 2GFSK) data from Analog Devices. The crystal-based architecture of the MAX41460 provides greater modulation depth, faster frequency settling, higher tolerance of the transmit frequency, and reduced temperature dependence. It integrates a fractional phase-locked loop (PLL); so a single, low-cost crystal of 16MHz used on this Click board™ can generate commonly used world-wide sub-GHz frequencies. A buffered clock-out signal makes the device compatible with almost any MCU or code-hopping generator. The MAX41460 feature fast oscillator Wake-Up upon data activity detection and has an Auto-Shutdown feature to extend battery life.

This Click board™ has four major operating states: Shutdown, Stand-By, Programming, and Transmitter-Enabled Mode. These states describe the Power-ON/Power-OFF status of the transmitter’s three primary internal circuit blocks: the crystal oscillator (XO), the PLL synthesizer, and a high-efficiency, open-drain switching-mode power amplifier (PA). To ensure the MAX41460 enters the shutdown state after Power-On, the DATA pin must be held low at Power-On. The PA pin is used to adjust the frequency with only frequency-dependent components required for the external antenna-matching network that are connected in such a way that the frequency of this Click board™ is fixed to 433.92MHz.

The MAX41460 communicates with MCU using the standard SPI serial interface with a maximum frequency of 20 MHz. The device can support two types of SPI transactions: register access only, and register access followed by data transmission. In both Shutdown and Stand-By states, programming through the SPI interface is not allowed. Configuration register values are retained in all states unless changed by programming, or if the device is powered off. This Click board™, alongside power LED indicator, has an additional green LED indicator labeled as DATA used to visually indicate the successful transmission of data across the SPI interface.

ISM TX Click possesses on itself the SMA antenna connector and it can be used for connecting the appropriate antenna that MikroE has in its offer such as Rubber Antenna GSM/GPRS Right Angle. This antenna is an excellent choice for all GSM/GPRS applications and supports a various range of frequencies and bands.

This Click board™ is designed to be operated only with a 3.3V logic voltage level. A proper logic voltage level conversion should be performed before the Click board™ is used with MCUs with different logic levels. However, the Click board™ comes equipped with a library that contains easy to use functions and an example code that can be used as a reference for further development.

Specifications

Pinout diagram

This table shows how the pinout on ISM TX Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
	NC	1	AN	PWM	16	NC
	NC	2	RST	INT	15	NC
SPI Chip Select	CS	3	CS	RX	14	NC
SPI Clock	SCK	4	SCK	TX	13	NC
SPI Data OUT	SDO	5	MISO	SCL	12	NC
SPI Data IN	SDI	6	MOSI	SDA	11	NC
Power Supply	3.3V	7	3.3V	5V	10	NC
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

ISM TX Click electrical specifications

Software Support

We provide a library for the ISM TX Click on our LibStock page, as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Library Description

Library provides functions for communication with Click board, specific ones to configure device, setting frequency, frequency deviation, baudrate, and one for sending(transmit) data.

Key functions:

• void ismtx_initial_cfg ( void ) – Function for initial configuration
• uint8_t ismtx_set_frequency ( uint32_t freq ) – Function for setting transmit frequency
• void ismtx_send_data ( uint8_t *tx_data, uint8_t tx_len ) – Function for transmiting data

Examples description

The application is composed of three sections :

• System Initialization – Initialization of CS pin and LOG module
• Application Initialization – Initialization for configuration, resets device, sets default configuration, and sets parameters for communication.
• Application Task – Sends predefined data every second.

void application_task ( )
{    
    ismtx_send_data( &data_send[ 0 ], 8 );
    mikrobus_logWrite( " *  Transmit done! *  ", _LOG_LINE );
    Delay_ms( 1000 );
}

Additional Functions :

• void manchester_spi_init ( void ) – Wrapper function over SPI init for sending data
• void normal_spi_init ( void ) – Wrapper function over SPI init for normal communication

The full application code, and ready to use projects can be found on our LibStock page.

Other mikroE Libraries used in the example:

• SPI
• UART

Additional notes and informations

Depending on the development board you are using, you may need USB UART click, USB UART 2 click or RS232 click to connect to your PC, for development systems with no UART to USB interface available on the board. The terminal available in all MikroElektronika compilers, or any other terminal application of your choice, can be used to read the message.

mikroSDK

This Click board™ is supported with mikroSDK – MikroElektronika Software Development Kit. To ensure proper operation of mikroSDK compliant Click board™ demo applications, mikroSDK should be downloaded from the LibStock and installed for the compiler you are using.

For more information about mikroSDK, visit the official page.