LITTLE WEB SERVER TF CARD
ESP32-S3 Super Mini + GC9A01 Display + Micro SD Card Reader
PIN CONNECTIONS
| COMPONENT | COMPONENT PIN | ESP32-S3 PIN | WIRE COLOR |
|---|---|---|---|
| GC9A01 Display | VCC | 3V3 | Red |
| GND | GND | Black | |
| SCL/SCLK | GPIO 12 | Yellow | |
| SDA/MOSI | GPIO 11 | Cyan | |
| RST | GPIO 10 | Purple | |
| DC | GPIO 9 | Orange | |
| CS | GPIO 8 | Green | |
| BL (Backlight) | GPIO 7 | White | |
| SD Card Reader (HiLetgo 6-Pin) |
GND | GND | Black |
| VCC | 3V3 | Red | |
| MISO | GPIO 3 | Brown | |
| MOSI | GPIO 2 | Cyan | |
| SCK | GPIO 4 | Yellow | |
| CS | GPIO 1 | Blue | |
| TP4056 Charger | OUT+ | ESP32 5V | Red |
| OUT- | ESP32 GND | Black | |
| B+ | Battery (+) | Red | |
| B- | Switch OUT | Black | |
| Power Switch | Input (IN) | Battery (-) | Black |
| Output (OUT) | TP4056 B- | Black | |
| 18650 Batteries (x2) | Positive (+) [Parallel] | TP4056 B+ | Red |
| Negative (-) [Parallel] | Switch IN | Black |
IMPORTANT NOTES
- Separate SPI Buses: The display and SD card use separate SPI buses to avoid conflicts. Display uses GPIO 11 (MOSI), GPIO 12 (SCK). SD card uses GPIO 2 (MOSI), GPIO 3 (MISO), GPIO 4 (SCK).
- SD Card Pins: CS=GPIO 1, MOSI=GPIO 2, MISO=GPIO 3, SCK=GPIO 4. Uses HSPI bus on ESP32-S3.
- Display Pins: CS=GPIO 8, DC=GPIO 9, RST=GPIO 10, MOSI=GPIO 11, SCK=GPIO 12, BL=GPIO 7.
- Level Conversion: The HiLetgo module has built-in level shifters, so it works with 3.3V logic from the ESP32-S3.
- Voltage Dropper Removal: The HiLetgo TF card module has an onboard voltage dropper (AMS1117 regulator) that drops 5V to 3.3V. Since we're already powering it with 3.3V from the ESP32, this regulator causes a voltage drop that can make the SD card unreliable. REMOVE the AMS1117 chip and solder a jumper wire between its input and output pads to bypass it. This allows the full 3.3V to reach the SD card.
- SD Card Format: Format your SD card as FAT32 with default allocation size for best compatibility.
- 5V Input: The TP4056 OUT+ provides ~4.2V (fully charged) to ~3.0V (discharged) from the batteries. This connects to the ESP32's 5V pin, which feeds the onboard voltage regulator. Despite the name "5V", the ESP32-S3 accepts 4.0-6.0V on this pin.
- 3.3V Output: The ESP32's internal LDO regulator converts the 5V input down to 3.3V. This 3.3V rail powers all external components (display, SD card reader). Never connect 5V directly to components - they require 3.3V!
- Power Switch: Located on the battery NEGATIVE rail between the 18650s and TP4056 B- pin. Placing the switch on the negative rail is safer - it completely isolates the batteries when OFF, preventing any current flow. Turn OFF before connecting USB to charge safely, as this prevents back-feeding the batteries during charging.
- Batteries: Two 18650 cells wired in PARALLEL (3.7V nominal, doubled capacity). Connect to TP4056 B+ and B- pins.
- Charging: TP4056 charges batteries via USB-C. Red LED = charging, Green LED = full.
- Web Files: Store your HTML, CSS, JS, and image files on the SD card instead of LittleFS for much larger storage capacity.