E-Paper ESP32-C6 Firmware

Firmware for an ESP32-C6 based E-Paper display device, featuring BLE provisioning, AWS IoT connectivity, and OTA updates. We use the firmware in our paperlesspaper OpenPaper 7. Check paperlesspaper Github for hardware source files.

Hardware Requirements

• Microcontroller: ESP32-C6-DevKitM-1
• Display: Spectra 6 7.3 (EL073TF1)
• Sensors: KXTJ3-1057 Accelerometer
• Other: Battery, Charger circuit (see Hardware Settings below)

Software Requirements

• IDE: Visual Studio Code
• Extension: PlatformIO
• Framework: Arduino (via PlatformIO)

Installation & Setup

1. Clone the Repository

   git clone <repository-url>
   cd epaper-espc6-firmware

2. Environment Configuration Create a .env file in the root directory with the following variables:

   ENV_OTA_URL="https://your-ota-server.com/firmware.bin"
   ENV_OTA_URL_DEV="https://your-dev-ota-server.com/firmware-dev.bin"
   ENV_WIFI_PW_DEPLOY="default_wifi_password"
   ENV_WIFI_SSID_DEPLOY="default_wifi_ssid"
   ENV_AWS_IOT_ENDPOINT="your-aws-iot-endpoint.iot.region.amazonaws.com"

3. AWS IoT Certificates The device requires AWS IoT certificates to connect. These are stored in the SPIFFS filesystem.

   • Naming Convention: The certificates must be named using the device's unique ID, which is epd7- followed by the MAC address (hex, uppercase, no colons).

     • Example MAC: A0:B1:C2:D3:E4:F5 -> UID: epd7-A0B1C2D3E4F5
     • Private Key: epd7-A0B1C2D3E4F5.key
     • Certificate: epd7-A0B1C2D3E4F5.crt

   • Upload:

     1. Create a data folder in the project root if it doesn't exist.
     2. Place your renamed .key and .crt files in the data folder.
     3. Run the PlatformIO task: Platform -> Upload Filesystem Image.

   Warning: These certificates are stored in the SPIFFS partition. If you change the partition table or erase the flash, the certificates will be lost, and the device will no longer connect to the cloud.

4. Build and Upload Firmware

   • Run the PlatformIO task: General -> Upload.

Usage Limits & Cloud Connectivity

• AWS IoT: This firmware heavily relies on AWS IoT Core for activation, status updates, and image retrieval. Ensure your AWS account is set up and limits/costs are monitored.
• BLE Advertising: The device advertises via BLE for provisioning. Advertising restarts automatically after a client disconnects.
• Deep Sleep: The device enters deep sleep to save power. It wakes up via:
  • Timer (configurable via MQTT).
  • Accelerometer (motion).
  • Button press.

Memory Map (EEPROM/Flash)

• 0-39: WiFi Name
• 40-105: WiFi Password
• 140: Reconnect Count
• 150: File Version
• 160: Activated Flag
• 170: Activation Counter
• 190: Display Revision Store
• 200: WiFi Lost State
• 210: Sleep Time
• 220: Dispay Orientation Store
• 500+: Settings Store

Hardware Settings

• Charger: Safety TMR 4h, 4-cell intermittent.
• Reset: 5+ presses
• OTA Force (Dev Firmware): 3-4 presses
• Boot Mode: Hold the small button, short press the reset button (big button) while holding the small button, then release the small button.