gCore Feather - A development board for portable gadgets

gCore ("Gadget Core") is an ESP32 development board designed to mate with the Adafruit TFT Featherwing 480x320 pixel 3.5" TFT LCD display with resistive touch. It contains a WROVER-B module, USB UART, true USB power-bath Li-Ion battery charger, a pair of ICR10440 batteries and a boost/buck 3.3V converter. It is designed to support soft-power control and battery voltage/charge status monitoring.  gCore came about because I wanted to develop devices using the LVGL GUI library and wanted a common platform so I wasn't always hacking various development boards together with a lot of extra circuitry for good power and charge control.

Design documentation and example software/libraries can be found on github.

There is a more detailed write-up of the project on hackaday.io.

This development board was superseded by a new version that became a product.
Hardware Features
  1. ESP32 WROVE-B - All ESP32 goodness with 16 MB PSRAM and 16 MB Flash memory.
  2. CP2102 USB UART - Reconfigured to support intelligent USB charging - Suspend detection, Enumeration detection (switches from 100 to 500 mA), charger detection (enables 500 mA charging).
  3. MCP73871 Load Sharing Charger - Intelligent power path that works around the common problem on a lot of dev boards that share load power with charge power. Automatically selects necessary power sources.
  4. TPS63051 Boost-Buck Converter - Provides 3.3V at all battery levels unlike many dev boards using linear or buck regulators that cause the DC supply to sag with low batteries.
  5. Soft power control - enables power on with a button and power-off under firmware control.
  6. Battery Voltage detection - Allows firmware to detect low-battery conditions for auto-shutoff.
  7. Charge state detection - Allows firmware to monitor charging.

Software Support
  1. Arduino library for battery monitoring and power control.
  2. LittlevGL drivers for the LCD and touch interface.
  3. Port of FabGL to gCore.
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gCore Block Diagram