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OpenDash — Hardware Specifications

Device Summary

Center Display — ESP32-S3-Touch-LCD-4.3

Parameter Value
Display 4.3" IPS LCD, 800×480 px, 65K colors
Touch 5-point capacitive (GT911 via I2C)
MCU ESP32-S3R8 (dual-core LX7 @ 240 MHz)
Flash 16 MB
PSRAM 8 MB
Interfaces CAN bus, RS485, I2C, UART, USB-C
Storage MicroSD (TF card) slot
Battery PH2.0 LiPo connector with charging
IO Expander CH422G
Waveshare Wiki ESP32-S3-Touch-LCD-4.3
LCD Controller Datasheet ST7262.pdf

ST7262 RGB Timing Parameters (Page 52 of Datasheet)

CRITICAL: These timing values must be within spec or the display will have random alignment on reset!

Parameter Min Typical Max Unit OpenDash Value
Pixel Clock (DCLK) 23 25 27 MHz 25 MHz
Horizontal
H Display Period - 800 - PCLK 800
HSYNC Pulse Width 2 4 8 PCLK 4
HSYNC Back Porch 4 8 48 PCLK 8
HSYNC Front Porch 4 8 48 PCLK 8
H Total 808 816 896 PCLK 820
Vertical
V Display Period - 480 - Lines 480
VSYNC Pulse Width 2 4 8 Lines 4
VSYNC Back Porch 4 8 12 Lines 8
VSYNC Front Porch 4 8 12 Lines 8
V Total 488 496 504 Lines 500

Note: Using typical values ensures stable, centered display output. Previous incorrect values (hsync_pulse=40, vsync_pulse=23) were far outside spec and caused unpredictable alignment behavior.

Pin Mapping (Center):

Function GPIO Notes
LCD Data (RGB) See wiki 16-bit parallel RGB interface
LCD Backlight GPIO2 PWM controllable
Touch SDA GPIO8 GT911 I2C data
Touch SCL GPIO9 GT911 I2C clock
Touch INT GPIO4 Interrupt pin
Touch RST GPIO48 Reset pin
I2C SDA (ext) GPIO15 External I2C bus (inter-node)
I2C SCL (ext) GPIO16 External I2C bus (inter-node)
CAN TX GPIO19 CAN bus transmit
CAN RX GPIO20 CAN bus receive
SD CMD GPIO40 SD card command
SD CLK GPIO41 SD card clock
SD D0 GPIO39 SD card data

Left & Right Gauges — ESP32-S3-LCD-2.8C

Parameter Value
Display 2.8" IPS LCD, 480×480 px, round, 160° viewing
Touch None (2.8C variant is non-touch)
LCD Driver ST7701 (RGB interface)
MCU ESP32-S3 (dual-core LX7 @ 240 MHz)
Flash 16 MB
PSRAM 8 MB (octal)
Waveshare Wiki ESP32-S3-LCD-2.8C

Pin Mapping (Left/Right):

Function GPIO Notes
LCD HSYNC GPIO39 Horizontal sync
LCD VSYNC GPIO41 Vertical sync
LCD DE GPIO40 Data enable
LCD PCLK GPIO42 Pixel clock
LCD D0–D15 Various 16-bit RGB data
LCD Backlight GPIO2 PWM controllable
LCD RST GPIO38 Display reset
I2C SDA (ext) GPIO15 External I2C bus (inter-node)
I2C SCL (ext) GPIO16 External I2C bus (inter-node)

Note: Left and right units use identical hardware and firmware. The unit's role (left vs. right) is configured via NVS at first boot or via the companion app.

GPS / Telemetry — ESP32-S3-Touch-AMOLED-1.75

Parameter Value
Display 1.75" AMOLED, 466×466 px, 16.7M colors
Display Driver CO5300 (QSPI interface)
Touch Capacitive (CST9217 via I2C)
MCU ESP32-S3R8 (dual-core LX7 @ 240 MHz)
Flash 16 MB
PSRAM 8 MB
GNSS LC76G module (GPS version)
IMU QMI8658 (3-axis accel + 3-axis gyro)
RTC PCF85063 (battery-backed)
PMIC AXP2101
Audio Dual MEMS microphones
Storage MicroSD (TF card) slot
Waveshare Wiki ESP32-S3-Touch-AMOLED-1.75

Pin Mapping (GPS):

Function GPIO Notes
AMOLED CS GPIO9 QSPI chip select
AMOLED SCK GPIO10 QSPI clock
AMOLED D0 GPIO11 QSPI data 0
AMOLED D1 GPIO12 QSPI data 1
AMOLED D2 GPIO13 QSPI data 2
AMOLED D3 GPIO14 QSPI data 3
AMOLED RST GPIO21 Display reset
Touch SDA GPIO1 CST9217 I2C data
Touch SCL GPIO2 CST9217 I2C clock
Touch INT GPIO3 Touch interrupt
GPS TX GPIO17 LC76G UART TX — NOT USED: GPS is I2C
GPS RX GPIO18 LC76G UART RX — NOT USED: GPS is I2C
GPS I2C GPIO15/14 LC76G via CASIC I2C (0x50/0x54/0x58, 100 kHz, shared bus)
IMU SDA GPIO5 QMI8658 I2C data
IMU SCL GPIO6 QMI8658 I2C clock
I2C SDA (ext) GPIO15 External I2C bus (inter-node)
I2C SCL (ext) GPIO16 External I2C bus (inter-node)
SD CMD GPIO40 SD card command
SD CLK GPIO41 SD card clock
SD D0 GPIO39 SD card data

Wiring — Inter-Node I2C Bus

All four nodes (Center, Left, Right, GPS) connect via a shared I2C bus:

        3.3V ──┬──── 4.7kΩ ────┬──── 4.7kΩ ────┐
               │                │                │
              SDA              SCL              GND
               │                │                │
    ┌──────────┼────────────────┼────────────────┼──────────┐
    │  CENTER  │  GPIO15(SDA)   │  GPIO16(SCL)   │  GND     │
    ├──────────┼────────────────┼────────────────┼──────────┤
    │  LEFT    │  GPIO15(SDA)   │  GPIO16(SCL)   │  GND     │
    ├──────────┼────────────────┼────────────────┼──────────┤
    │  RIGHT   │  GPIO15(SDA)   │  GPIO16(SCL)   │  GND     │
    ├──────────┼────────────────┼────────────────┼──────────┤
    │  GPS     │  GPIO15(SDA)   │  GPIO16(SCL)   │  GND     │
    └──────────┴────────────────┴────────────────┴──────────┘

Important: Use 4.7kΩ pull-up resistors on SDA and SCL lines. Only one set of pull-ups is needed per bus (not per device).

Power Supply

Each ESP32-S3 device can be powered via USB-C (5V) or directly from a regulated 3.3V/5V supply. For automotive use:

  1. Use a 12V-to-5V DC-DC buck converter (rated for automotive voltage spikes)
  2. Add reverse polarity protection (Schottky diode or P-FET)
  3. Add EMI filtering capacitors near each device
  4. Consider a separate 5V rail for each device to prevent ground loops