The 4x4 Macropad design was inspired from the 4x4 macropad from 40 percent club.
Processor and Module
The Macropad 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 Macropad 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 specific 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.
Although the Macropad 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 Macropad. The Adafruit nRF52832 Feather bootloader is fully compatible with the Macropad.
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