Silicon Labs BT122-DK4315B

Overview

BT122-DK4315B from Silicon Labs is a Bluetooth Dual Mode (BR/EDR + BLE) development kit centered on the BT122 module, featuring an on-board J-Link debugger, Si7021 temperature/humidity sensor, dual USB Micro-B ports (Debug + UART), and breakout pads for GPIO, UART, SPI, I²C, and ADC interfaces. It supports BGAPI host control and BGScript standalone operation for rapid prototyping of Bluetooth-connected embedded systems.

For engineers reviewing the BT122-DK4315B datasheet, BT122-DK4315B pinout, BT122-DK4315B application, or BT122-DK4315B equivalent, this kit enables hands-on validation of Bluetooth dual-mode stack integration, low-power energy profiling via AEM, firmware update via J-Link/SWD or UART DFU, and sensor-augmented BLE peripheral development - all without external debug hardware.

Technical Context

The BT122-DK4315B implements the BRD4315B reference design, integrating the BT122 Bluetooth 4.2 Dual Mode module with an independent on-board J-Link debugger MCU that provides SWD programming, VCOM bridging (up to 3 Mbps), and EM4S ultra-low-power shutoff (~20 nA). The board routes all BT122 GPIOs-including PA0, PC8–PC9, PF0–PF5-to accessible breakout pads with 5V-tolerant capability on eight pins.

It includes a factory-calibrated Si7021 I²C humidity/temperature sensor, dual USB Micro-B connectors (one for Debug/J-Link/VCOM, one for dedicated UART bridge), Mini Simplicity connector for WSTK-based AEM energy measurement, and user-controllable push buttons/LEDs tied to PF2/PF3 with RC debouncing (1 ms time constant).

Key Specifications

Availability

BT122-DK4315B is available at Aetrix Electronics and suitable for Bluetooth protocol validation, BLE sensor node development, dual-mode HID device prototyping, and low-power wireless connectivity testing requiring stable component supply and full evaluation board support.

Supply support for BT122-DK4315B includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Silicon Labs is a fabless semiconductor company specializing in secure, intelligent wireless and wired connectivity solutions for IoT, industrial, and consumer applications.

The BT122-DK4315B belongs to Silicon Labs' Bluetooth Development Kit product line, designed to accelerate end-to-end development of certified Bluetooth Dual Mode applications-from stack configuration and sensor integration to power optimization and regulatory RF testing.

FAQ

What is the primary function of the BT122-DK4315B?

The BT122-DK4315B is a complete development kit for the BT122 Bluetooth Dual Mode module. It provides hardware access to all module interfaces, integrated debugging via on-board J-Link, sensor-augmented BLE prototyping with Si7021, and full SDK toolchain support (BGTool, BGBuild, BGScript) - enabling rapid development and validation of Bluetooth BR/EDR and BLE applications without external tooling.

Does the BT122-DK4315B support energy consumption measurement?

Yes, the BT122-DK4315B supports precise energy profiling via its Mini Simplicity connector, which interfaces directly with Silicon Labs Wireless Starter Kits (WSTK) equipped with Advanced Energy Monitor (AEM). When the USB cable is disconnected, the on-board debugger enters EM4S mode (~20 nA), isolating BT122 and peripherals (Si7021, LEDs, buttons) for accurate current draw measurement during active or sleep states.

Can the BT122-DK4315B be programmed without a J-Link debugger?

Yes, the BT122-DK4315B supports three programming methods: (1) J-Link/SWD via USB Debug port (primary method), (2) UART DFU via USB UART port using BGAPI commands like dfu_reset(1), and (3) Mini Simplicity connector when paired with a WSTK acting as external J-Link. All methods are fully supported by the BT122 SDK and BGTool interface.

What communication interfaces does the BT122-DK4315B expose for custom hardware integration?

The BT122-DK4315B exposes 10 BT122 GPIOs (PA0, PC8–PC9, PF0–PF5) on labeled breakout pads, with UART (TX/RX/CTS/RTS), SPI (CLK/CS/MISO/MOSI), I²C (SCL/SDA), ADC (CH0–CH2), and SWD (SWCLK/SWDIO/SWO) signals fully routed and documented. Eight pins are 5V-tolerant, enabling direct interfacing with common logic-level peripherals.

Is the Si7021 sensor on the BT122-DK4315B factory-calibrated and usable out-of-box?

Yes, the Si7021 relative humidity and temperature sensor on the BT122-DK4315B is factory-calibrated and communicates over I²C at standard address 0x40. It delivers ±0.3 °C temperature accuracy and ±3 %RH humidity accuracy. For highest thermal accuracy, power the board via Mini Simplicity connector instead of USB to avoid self-heating drift from the on-board LDO.