Spotpear ESP32C3 1.44 LCD

The Spotpear ESP32C3 1.44 LCD board combines a ESP32-C3 with a display and LIPO charging with a compact design.

The Spotpear ESP32C3 board with 1.44 inch LCD display is a very compact version of a LCD + ESP32C3 combination.

Features

ST7735 128*128 display on SPI bus
3 custom buttons
reset button
LED
LiPo charger
USB bust directly connected to ESP32C3

Arduino Board Configuration

The Arduino Board Manager supports this board by installing the esp32 by espressif package and using the following settings:

Board: ESP32C3 Dev Module
Upload Speed: 921600
USB CDC On Boot: Enabled
CPU Frequency: 160 MHz
Flash Frequency: 80MHz
Flash Mode: QIO
Flash Size: 4MByte (32Mbit)
Partition Scheme: Default 4MB with spiffs (1.2MB App/1.5MB SPIFFS)
Core Debug Level: None
Erase All Flash: Disabled
JTAG Adapter: Integrated USB JTAG

For compiling with the Arduino CLI the following board settings can be used:

"board": "esp32:esp32:esp32c3",
"configuration": "JTAGAdapter=default,CDCOnBoot=cdc,PartitionScheme=default,CPUFreq=160,
  FlashMode=qio,FlashFreq=80,FlashSize=4M,UploadSpeed=921600,DebugLevel=none,EraseFlash=all"

Display

The display is driven by a ST7735 chip and can be used within the Homeding library by including the Display ST7735 Element

It is driven by the standard SPI interface that is configured in the Device Element.

You can find the full settings in the system configuration below.

Momentary Buttons

There are 4 momentary buttons on the board. 3 of them are pulling a GPIO pin to ground and one is connected to the EN and will reset the processor.

Pins used: IO8, IO10, Boot = IO9, Reset = Chip_EN

There are no external pull-up resistors on the board so the internal pullup resistors of the ESP32-C3 must be enabled.

Connector

The connector pins that can be used for external communication or sensors. The following GPIO pins and power connectors are available:

Pin	Function
1	GPIO1
2	GPIO6
3	GPIO7
4	GPIO20
5	GPIO21
6	GND

It is a bit tricky to solder connector pins to the existing soldering pads as the display is nearby glued to the printed circuit board.

On the opposite side of the printed circuit board there are 2 labeled connectors that can provide 3.3V and the charging voltage from the USB connector.

LEDs

There is a LED connected to the GPIO pin # 11 next to the reset button.

However this pin cannot be freely used and is connected to the VCC for the internal SPI flash. It will turn off when the board goes into the deep sleep mode.

LiPo charging

There is a PL4054 chip on the board that charges a connected LiPo battery using the USB power.

The PL4054 is a linear Li-Ion Battery Charger that has no further interface or API for control.

System configuration

The following env.json file can be used as a starting point for the configuration of this board and includes all definitions for the on-board hardware:

{
  "device": {
    "0": {
      "name": "spotpearc3",
      "title": "Spotpear 1.44 LCD",
      "description": "Spotpear ESP32C3 board with 1.44 inch LCD display",
      "loglevel": "2",
      "logFile": "1"
    }
  },
  "ota": {
    "0": {}
  },
  "ntptime": {
    "0": {
      "zone": "CET-1CEST,M3.5.0,M10.5.0/3"
    }
  },
  "DisplayST7735": {
    "0": {
      "description": "Display",
      "loglevel": 2,
      "width": "128",
      "height": "128",
      "colOffset": 2,
      "rowOffset": 1,
      "busmode": "spi",
      "spiClk": 3,
      "spiMosi": 4,
      "resetPin": 5,
      "spiDC": 0,
      "spiCS": 2,
      "rotation": 180,
      "background": "#002200"
    }
  },
  "state": {
    "0": { "savedelay": "8s" }
  },
  "digitalin": {
    "boot": {
      "title": "Boot button signal",
      "pin": "9",
      "invert": "true",
      "pullup": "1"
    },
    "key1": {
      "title": "Key 1",
      "pin": "8",
      "invert": "true",
      "loglevel": "2",
      "pullup": "1"
    },
    "key2": {
      "title": "Key 2",
      "pin": "10",
      "invert": "1",
      "pullup": "1"
    }
  }
}