Technical summary
LILYGO® has just launched a board ESP32-C3 with a rechargeable battery holder 16340. The new board, aptly named LILYGO TTGO T-OI PLUS, consumes less power because its single-core RISC-V SoC processor uses respectively 5uA and 130uA in deep sleep and light sleep modes, unlike its ESP8266 and ESP32 counterparts which consume respectively about 20uA and 2000uA in deep sleep and light sleep modes.
The TTGO T-OI PLUS has the ability to charge the battery LiPo connected through its charging circuit. The board's battery level can be monitored with software using a few lines of code to read the voltage divider signature on its A0 pin. The board also comes with 3 LEDs: green (indicates communication over UART), blue (charging indicator) and red (always-on power indicator). A GitHub user who made a small tweak with the board stated that the red LED can be turned off manually by removing it with a screwdriver. This adjustment did however reduce the overall deep sleep current from 1 mA to 110 uA, which is undoubtedly acceptable if one wishes to avoid a fast battery discharge.
The TTGO T-OI PLUS board also has the same header pinout as the T-OI ESP8266 board, so it is safe to say that both have compatible expansion modules.
The board's features and specifications include:
- 32-bit ESP32-C3 single-core RISC-V processor from Espressif Systems with:
- 160 MHz clock speed
- 400 KB SRAM, 384 KB ROM and 8 KB SRAM in RTC
- 2x 12-bit SAR ADC, up to 6 channels
- 3 x SPI, 2 x UART, 1 x 12C, 1 x 12S, LED PWM, TWAI, timers, RMT, full-speed USB serial
- IEEE802.11b/g/n compliant, stations supported, SoftAp, SoftAp + station mode
- Bluetooth 5.0, Bluetooth mesh
- 2 MB or 4 MB flash memory
- Ceramic antenna and IPEX connector
- USB-C port for power and programming
- 2x 8-pin headers with 12x GPIO, 1x SPI, 1x UART, 3x ADC, 5V, 3.3V, GND
- 4-pin 2.0mm Grove I2C connector
- Power and charging indicators
- Reset button
- Power switch
- Power supply
- 5V power supply via the USB Type-C port
- Battery holder for 3.7V 16340 LiPo battery plus charging circuit
- Dimensions: 45.7 mm x 25.8 mm x 15.8 mm
- The code for TTGO T-OI PLUS is available on Github, as made available by LILYGO. The code is entirely written in C++, although the available documentation was initially written for T-OI ESP8266 and may require some adjustments to work properly.
