BlueMicro V2.1

Description

The BlueMicro V2.1 expands on the BlueMicro V1.x and V2.0 by adding a serial chip to the breakout board for the Ebyte E73-2G4M04S1B module (nRF52832). This serial chip allows for programming the BlueMicro without the need for any additionnal hardware and simplifies the process since the serial chip is also connected to the reset circuitry. The charger is still powered by connecting a standard micro-usb cable to a computer or regular 5V charger. The pinout still matches that of the Arduino Pro Micro. The Raw pin is meant to be connected to the LiPo battery for powering on the BlueMicro.

Since the serial GPIOs are directly connected to the serial chip, the pinout differs slightly from the BlueMicro v2.0.

Processor and Module

The BlueMicro uses the nRF52832 from Nordic Semiconductors. For an overview of the features of this SoC, refer to Nordic's Product Page. The most important features are as follows:

  • 64 MHz Cortex-M4 with FPU
  • 512 KB Flash, 64 KB RAM
  • 2.4 GHz Transceiver
  • -20 to +4 dbm programmable TX Power
  • 32 configurable GPIOs

For a detailed description of the nRF52832, you can download the datasheet (533 pages).

The BlueMicro uses the Ebyte E73-2G4M04S1B module. This module is FCC and CE certified.
The module uses a PCB antenna, has an external antenna connector and makes 30 GPIOs available externally, 1 of which is reserved for the reset button. The bootloader and firmware may reserve additional GPIOs for specific functions (2 pins for serial, 1 pin for factory reset, 1 pin to put in DFU) For a detailed description of the module, refer to the manual.

If you want to replace the PCB antenna with an external antenna, the following antenna is the one that's designed by the module manufacturer. The manual indicate the small surface mount resistor that needs moving to disconnect the PCB antenna and connect the external antenna.

Bootloader

Although the BlueMicro can be programmed using the Nordic Software Development Kit and other commercial tools, we recommend using the open source Adafruit nRF52 Bootloader as the bootloader for the BlueMicro. The Adafruit nRF52832 Feather bootloader is fully compatible with the BlueMicro.

You can obtain the bootloader from the following locations:

  • release artifacts of the Adafruit Repo
  • release artifacts of the Forked Repo
  • Adafruit nRF52 Arduino Board Support Package
  • Community Add-on to Adafruit nRF52 Arduino Board Support Package

Pinout

PCB

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Schematic

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