The WaveShare ESP32-S3-Touch-LCD-3.5B board is equipped with:
| Chip | Type / Function | What it does (short) |
|---|---|---|
| AXS15231B | Display Driver and Touch Panel Controller | Drives LCD/TFT displays and touch panels |
| QMI8658 | IMU sensor | 6-axis motion sensing (accelerometer + gyroscope) |
| PCF85063 | Real-Time Clock (RTC) | Keeps date/time with ultra-low power |
| AXP2101 | Power Management IC (PMIC) | Battery charging, power regulation, power sequencing |
| ES8311 | Audio Codec | Audio ADC/DAC for mic input and speaker/headphone out |
| W25Q128JVSIQ | External SPI flash memory | 16MB NOR-Flash Memory |
| TCA9554 | Port Expander | Provides extra connections to e.g. LCD and Touch lines |
Block diagram:
flowchart LR
USB[USB Type-C<br/>VBUS + USB D±]
ESP[ESP32-S3<br/>Wi-Fi / BLE MCU]
FLASH[SPI Flash<br/>W25Qxx]
LCDDRV[AXS15231B<br/>LCD and Touch Controller]
LCD[LCD Panel<br/>Backlight]
AUDIO[ES8311<br/>Audio Codec]
AMP[NS4150B<br/>Audio Amplifier]
SPK[Speaker / Mic]
IMU[QMI8658<br/>6-axis IMU]
RTC[PCF85063<br/>RTC]
IOX[TCA9554<br/>I/O Expander]
PMIC[AXP2101<br/>PMIC + Charger]
BAT[Li-Ion Battery]
%% Connections
USB -->|VBUS / USB| ESP
USB -->|VBUS| PMIC
PMIC -->|3V3 / 2V8 / RTC| ESP
PMIC -->|Power Rails| LCDDRV
PMIC -->|Power Rails| AUDIO
PMIC -->|Power Rails| IMU
PMIC -->|Power Rails| RTC
PMIC -->|Power Rails| IOX
BAT --> PMIC
ESP -->|SPI / QSPI| FLASH
ESP -->|SPI / QSPI| LCDDRV
LCDDRV --> LCD
ESP -->|I²C| LCDDRV
ESP -->|I²C| IMU
ESP -->|I²C| RTC
ESP -->|I²C| IOX
ESP -->|I²C| PMIC
ESP -->|I²S| AUDIO
AUDIO --> AMP
AMP --> SPK
Mapping between ESP chip and the AXS15231B controller:
| Signal | GPIO |
|---|---|
| LCD_CS | GPIO12 |
| LCD_SCLK | GPIO5 |
| LCD_DATA0 | GPIO1 |
| LCD_DATA1 | GPIO2 |
| LCD_DATA2 | GPIO3 |
| LCD_DATA3 | GPIO4 |
| LCD_BL | GPIO6 |
and for the Touchscreen interface (TP interface):
| Signal | Connection |
|---|---|
| TP_SCL | GPIO7 |
| TP_SDA | GPIO8 |
| TP_INT | Accessible via GPIO expander TCA9554PWR |
The GPIO expander (ESP) TCA9554PWR is connected to the ESP32 chip using the I2C bus:
| Signal | GPIO |
|---|---|
| ESP_SCL | GPIO7 |
| ESP_SDA | GPIO8 |
I measured the board power consumption to be roughly:
- 160mA at startup
- 110mA in idle
powering the board at 5V through the back-of-the-board connector. This shows an amazing <1W power consumption!