Introduction: The NRF52840 is a ProMicro-compatible development board designed for use with Nice! Nano. It features the same pin layout as the ProMicro, making it suitable for most ProMicro-based keyboards. The development board includes a 3.7V lithium battery interface and a software-controlled power switch for the LED. When the LED is disabled, the standby power consumption can be as low as 1mA. The nRF52840 is a high-performance, low-power wireless SoC that supports multiple protocols including Bluetooth 5, Thread, Zigbee, ANT, and 2.4GHz proprietary protocols. It integrates an ARM Cortex-M4F processor running at 64MHz, with 1MB of flash memory and 256KB of RAM. The board offers a wide range of peripherals such as ADC, PWM, SPI, I2C, UART, USB, and GPIO. It also supports advanced security features including hardware encryption, SHA-256 hashing, and a True Random Number Generator (TRNG). Product Parameters: - Wireless capability: Bluetooth 5.0 - Onboard antenna - Processor: nRF52840 with ARM Cortex-M4F, 64MHz - Memory: 1MB flash, 256KB RAM - Battery charging circuit: supports lithium battery charging and discharging - Power consumption: as low as 1mA in standby mode - Form factor: ProMicro compatible - Material: PC, Metal - Color: Black Package Contents: 1 x NRF52840 Development Board Note: The package includes only the items listed above. Other accessories are not included. Note: Lighting conditions and display settings may cause slight variations in the color of the product as shown in images. Measurement error is +/- 1-3cm.