# ESP32 - GC9A01 Manual # 1.28-Inch ESP32 Round TFT Screen Development Board **Date:** 2024/09/24 **Version:** V1.12 ## Revision History | Date | Version | Release Notes | |------------|---------|--------------------------------------------------------------------------------------------------------| | 2023-08-31 | V1.0 | First release | | 2023-11-07 | V1.01 | Added circuit descriptions for user modifications | | 2024-03-28 | V1.1 | Optimized button feel with better quality buttons; improved power efficiency to reduce heat and extend battery life; optimized antenna matching circuit, added IPEX antenna socket; added jumper for power-on bypass for user control of power button function; added 5.1K pull-down resistor for Type-C CC pin; added FPC expansion IO and baseboard for easier external sensor connections; used a diode to prevent USB voltage from directly entering the battery, removed the diode that prevented battery voltage from entering the USB port (battery voltage typically does not backfeed into USB). | | 2024-07-04 | V1.11 | Revised manual content, serial port needs to enable power recognition | | 2024-09-24 | V1.12 | Added FPC interface description | ## 1. Product Introduction The development board features a 1.28-inch round TFT screen, driven by the GC9A01 chip, with a resolution of 240x240 and 65K colors for clearer display. The screen connects to the onboard ESP32 via SPI, providing example drivers for easier usage. The development board has a USB port for one-click program downloads or serial communication; it can also be powered through this USB port. Additionally, it includes a battery interface and charging circuit. If a 3.7V lithium battery is connected, it can be charged via the USB port. The battery level is monitored through two voltage divider resistors connected to the ESP32's IO port, allowing for voltage reading to estimate the battery level. The board includes three side buttons and a TF card slot for direct TF card insertion. One button is the power switch, while the other two are customizable buttons that users can program as needed. If the buttons are too small for your enclosure, you can solder wires to the pads next to the buttons to connect external buttons. ## 2. Parameter Summary - **Product Type:** ESP32-TFT Development Board Series - **Input Voltage:** USB-5V / 3.7V-BAT (only supports calibrated 3.7V lithium batteries) - **Operating Current:** Related to code execution, typically does not exceed 100mA ### ESP32 Minimum System Parameters - **Operating Frequency:** 240MHz - **Core Count:** 2 - **Flash Size:** 16Mbyte - **PSRAM:** 8Mbyte (current version supports 4Mbyte space) - **Antenna:** Yes, onboard + IPEX (default onboard antenna) - **Wireless:** Bluetooth + WiFi 2.4G - **Screen Type:** TFT IPS - **Peripherals:** - TF card slot x1 - User-defined buttons x2 - 1.28-inch GC9A01 TFT screen x1 - Battery voltage collection interface x1 - **Mounting Method:** M2 copper pillars - **Size Reference:** - 41mm (H) x 37mm (W) - without card - 41mm (H) x 44mm (W) - with card (Manual measurement may have deviations) ## 3. Product Description ## 4. Function Block Description 1. **TYPE-C** The TYPE-C interface can be used for power supply, battery charging, program downloading, and serial communication. When using the TYPE-C for power, connect it to a USB 3.0 port or phone charger to avoid insufficient current causing restarts. During tests, powering via some docking stations while enabling WiFi and Bluetooth may cause reboots due to high current consumption. Charging uses a maximum current of 500mA charging chip. Given the small size, some users may use smaller capacity batteries, and the product itself generates considerable heat. The default maximum charging current is limited to around 300mA. If you need a higher current, you can replace the resistor. In most cases, increasing charging current is not recommended due to increased heat generation; see the table for details. | Resistance (Ω) | Charging Current (mA) | |----------------|-----------------------| | 20K | 50 | | 10K | 100 | | 5K | 200 | | 4K | 250 | | 3K | 300 | | 2K | 400 | | 1.6K | 500 | Programming can be done directly; the board has an automatic download circuit that can control the ESP32 reset and IO0 ports via serial RTS and DTR. The board is pre-programmed to play video from an SD card, so if programming fails, check user device settings or power supply. By default, the power switch is off when powered on; please turn it on before programming. The serial chip uses CH343 for high-speed serial communication, with a rate up to 6M, exceeding the maximum serial rate of the ESP32, effectively avoiding packet loss issues seen with CH340 and CP2102 at 4M. 2. **Battery Information** Ensure the positive and negative are not reversed, and take care during soldering. There is no onboard lithium battery over-discharge protection, so the battery will still discharge below 3V. When selecting a battery, choose one with protection to avoid over-discharge. The static current in the off state is below 1µA, so there’s no concern about rapid battery depletion when not in use. 3. **TF Card Compatibility** The TF card has been tested with 1G, 2G, and 32G with no issues; choose branded cards for better reliability. The factory can provide versions with a 2G TF card or without one. If you need a TF card, please purchase the appropriate version. 4. **Battery Voltage Detection** For battery voltage detection, the battery passes through a Schottky diode, followed by a 20K resistor and a 10K pull-down resistor for measurement, so consider the Schottky voltage drop (about 0.4V). The precision is not very high; hence, high-precision detection of battery level is not recommended. 5. **Wireless Performance** Due to the compact size of the product, significant sacrifices were made in the wireless section, without standard spacious areas for clear signals. Testing showed WiFi range indoors is about 20 meters (faster speeds result in shorter ranges). It has not been tested in open areas. Users can switch jumper resistors to use an external IPEX antenna, which greatly enhances signal quality. 6. **Power Switch** The power switch button is off by default on power-up, allowing battery charging but not serial recognition; ESP32, TFT screen, and TF card power are off. Users can switch to power-on operation using the J1 jumper pad, but button functions will be disabled. 7. **Extended IO Function Reference Diagram** ## 5. Size Description These dimensions are for the PCB board only and do not account for components outside the board outline. ## 6. Functional Block Diagram The product is not open-source. Detailed circuit diagrams are not provided, but connection diagrams for various functional blocks are included. These diagrams are sufficient for secondary development of the product; detailed diagrams can be found in the PDF document. ## 7. Precautions 1. The product has a small size and high integration, which results in considerable heat generation; this is normal and does not affect functionality. 2. The M2 copper pillar height is 4.5mm; ensure screws used do not exceed this height. 3. Regarding the external PFC interface, the provided 3.3V output port is connected to the ESP32 operating power. When using external power from the extension port, avoid connecting high-power devices, especially inductive devices like motors, as they can negatively affect or even damage the ESP32. 4. The provided examples can test the main functions; more improvements will be made gradually. If you have further suggestions, please share them with us to enhance the product. Thank you for your support.