MDBT42Q Click

How does it work?

MDBT42Q Click is based on the MDBT42Q-AT2 module from RAYTAC designed to provide Bluetooth Low Energy (BLE) connectivity. This certified BT 5.2 stack module is based on the Nordic nRF52810 SoC, a highly integrated solution that combines a 32-bit ARM Cortex-M4F processor with 192kB of Flash memory and 24kB of RAM, ensuring efficient operation in wireless applications. Acting exclusively in the peripheral/slave role, the module comes preloaded with RAYTAC’s AT command firmware, which simplifies configuration and control through a UART interface. As a recommended third-party module by Nordic Semiconductor, MDBT42Q-AT2 meets multiple international standards, being certified for FCC, IC, CE, Telec (MIC), KC, SRRC, and NCC compliance, while its onboard chip antenna guarantees excellent connectivity performance in compact embedded designs.

The module offers flexible configuration options, allowing users to choose on-air data rates of either 1Mbps or 2Mbps, set transmission power across five selectable levels, and adjust advertising time. For better user interaction, it supports customizable LED indication patterns that reflect advertising and connection status, with a yellow CONN/ADV LED as a clear status marker. To optimize energy consumption, it provides both DC-to-DC and LDO power modes, a dedicated power-down state with GPIO wake-up support, and efficient use of resources to extend battery life in portable systems.

Its data handling capabilities include support for a maximum MTU size of 247 bytes, enabling payloads of up to 244 bytes, ensuring reliable and flexible data exchange in BLE applications. With these features, MDBT42Q Click is ideal for IoT devices, wireless sensors, smart home automation, asset tracking systems, healthcare and fitness monitors, and other scenarios where low-power, short-range wireless connectivity is required.

This Click board™ establishes communication between the MDBT42Q-AT2 module and the host MCU through a UART interface, using standard UART RX and TX pins and hardware flow control via CTS and RTS pins. The default communication speed is set at 115200bps, ensuring efficient data exchange. In addition to the UART pins for communication with the module, this Click board also features a PD active-high pin used to enable the UART interface, a reset pin (RST) enabling easy module resetting, blue IND LED indicator for Bluetooth connection status (also available through IND pin), and SWD pads designed for use with MIKROE's 6-pin Needle Cable, providing an optional flash and debug SWD (Serial Wire Debug) interface functionality.

The board integrates dedicated wake-up buttons that provide a reliable way to bring the module out of deep sleep mode. Since the wake-up mechanism is logic-selective, it requires a clearly defined signal transition to activate the module, which is why two separate buttons are provided: one tied to the 3V3 rail and the other to GND. By pressing either of these, a valid high or low logic level is momentarily introduced, triggering the wake-up event in accordance with the module’s power management logic.

The board is also equipped with a set of carefully placed test points that provide developers with easy access to key signals for debugging, monitoring, and feature expansion. A dedicated group of test points labeled P12 through P19 enables support for up to eight programmable GPIO outputs, offering flexibility to configure these pins according to application requirements. In addition to general-purpose I/O, an ADC test point is also provided, allowing straightforward retrieval of analog-to-digital conversion values. This feature is particularly useful for monitoring supply conditions, most notably battery voltage levels, ensuring that power status can be tracked in real time and incorporated into the system’s operation logic.

This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. It also comes equipped with a library containing functions and example code that can be used as a reference for further development.

Specifications

Pinout diagram

This table shows how the pinout on MDBT42Q Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
BT Connection Indicator	IND	1	AN	PWM	16	PD	UART Enable
Reset / ID SEL	RST	2	RST	INT	15	RTS	UART RTS
UART CTS / ID SEL	CS	3	CS	RX	14	TX	UART TX
	NC	4	SCK	TX	13	RX	UART RX
	NC	5	MISO	SCL	12	NC
	NC	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

MDBT42Q Click electrical specifications

Software Support

MDBT42Q Click demo application is developed using the NECTO Studio, ensuring compatibility with mikroSDK's open-source libraries and tools. Designed for plug-and-play implementation and testing, the demo is fully compatible with all development, starter, and mikromedia boards featuring a mikroBUS™ socket.

Example Description

This example demonstrates the use of MDBT42Q Click board by processing data from a connected BT device.

Key Functions

• mdbt42q_cfg_setup This function initializes Click configuration structure to initial values.
• mdbt42q_init This function initializes all necessary pins and peripherals used for this Click board.
• mdbt42q_get_ind_pin This function returns the BT connection active indicator (IND) pin logic state.
• mdbt42q_reset_device This function resets the device by toggling the reset pin logic state.
• mdbt42q_cmd_run This function sends a specified command to the Click module.
• mdbt42q_cmd_set This function sets a value to a specified command of the Click module.

Application Init

Initializes the driver and logger.

Application Task

Application task is split in few stages:

• MDBT42Q_POWER_UP:

  Powers up the device, performs a factory reset and reads system information.

• MDBT42Q_CONFIG_EXAMPLE:

  Sets the BT device name.

• MDBT42Q_EXAMPLE:

  Performs a BT terminal example by processing all data from a connected BT device and sending back an adequate response messages.

Application Output

This Click board can be interfaced and monitored in two ways:

• Application Output - Use the "Application Output" window in Debug mode for real-time data monitoring. Set it up properly by following this tutorial.
• UART Terminal - Monitor data via the UART Terminal using a USB to UART converter. For detailed instructions, check out this tutorial.

Additional Notes and Information

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.