This is a fork of the Arduino core for GD32 MCUs (https://github.com/CommunityGD32Cores/ArduinoCore-GD32) with support for BIGTREE_GD_TFT35_E3_V3_0 board (https://github.com/bigtreetech/BTT-TFT35-E3-V3.0) which is based on GD32F205 MCU.
Additional resources:
To compile for this core with the Arduino IDE, add the following URL to the boards manager.
https://raw.githubusercontent.com/vovan888/ArduinoCore-GD32/main/package_gd32_index.json
This will install the core and compiler toolchain against the 'main' git branch.
Original description: https://github.com/bigtreetech/BTT-TFT35-E3-V3.0/tree/master/Hardware Pins that can be used in projects can be found in BTT TFT35-E3 V3.0PIN.pdf. (Please note that all connectors are displayed on the LCD side)
Some board hardware pins can be found on board connectors (EXP1, EXP2, EXP3), so if you us them as digital outputs you can't use board hardware connected to them.
Board supports flashing over ST-LINK debugger and programmer over SWD interface.
(https://www.st.com/en/development-tools/st-link-v2.html)
Driver (https://www.st.com/en/development-tools/stsw-link009.html)
ST-LINK utility (https://www.st.com/en/development-tools/stsw-link004.html)
You need to connect ST-LINK programmer (pins GND, SWDIO, SWCLK, 3.3V) to SWD connector on the board. Board can be powered from ST-LINK programmer via 3.3V pin without external power adapter for programming purposes. When using external power adapter you should disconnect 3.3V pin.
Warning! Before flashing board with Arduino backup your board flash with ST-LINK utility. After flashing sketches you will not be able to restore board's original firmware from SD card because original board's bootloader will be overwritten. Use ST-LINK to restore it if you need to go back to the original firmware.
How to backup board's flash:
1. Connect board to ST-LINK programmer and run ST-LINK utility.
2. Click "Target" -> "Connect"
3. In field "Address" you should see "0x08000000" . In field "Size" paste "0x40000" and press enter.
4. After that ST-LINK reads controller flash memory to ST-LINK Utility.
5. Now save memory to file. Click "File" -> "Save file as..". Paste filename and press "Save" button.
Board has 4 hardware serial outputs. Default Arduino's 'Serial' output is configured to UART4(RX4,TX4) connector on the board. This default can be changed, for example, to the RS232 port by changing "#define SERIAL_UART_INSTANCE 4" to “#define SERIAL_UART_INSTANCE 2” in the variant.h file (i.e. On Windows 10 this file is locate at %AppData%\Local\Arduino15\packages\STM32\hardware\stm32\1.9.0\variants\BIGTREE_F207VCT6 directory).
| Arduino instance | MCU interface | Board connector | Board pins |
|---|---|---|---|
| Serial1 | USART0 | WIFI | RX1 and TX1 |
| Serial2 and Serial | USART1 | RS232 | RX2 and TX2 (pins may be labelled wrongly, if this port does not work - try to switch RX2 and TX2 pins around) |
| Serial3 | USART2 | UART3 | RX3 and TX3 |
| Serial4 | UART3 | UART4 | RX4 and TX4 |
Pins:
PA10 SERIAL_RX1
PA9 SERIAL_TX1
PA3 SERIAL_RX2
PA2 SERIAL_TX2
PB11 SERIAL_RX3
PB10 SERIAL_TX3
PC11 SERIAL_RX4
PC10 SERIAL_TX4
Can be used as standard Arduino serial ports:
Serial.begin(115200);
Serial.println("Test");
//for other serial outputs use instance Serial1 .. Serial4:
// Serial1.begin(115200);
// Serial1.print("Test");
I2C interface uses the same pins as Serial3. So both USART2 and I2C1 cannot be used at the same time.
PIN_WIRE_SDA PB11
PIN_WIRE_SCL PB10
Use builtin library Wire.
Pin:
PD13 BUZZER_PIN
Standard Arduino function tone() can be used:
tone(PD13, Note, noteDuration);
Example:
tone(PD13, 440, 500); // play 440Hz for 500ms
LCD is connected to 16-bit parallel port in EXMC (External Memory Controller) mode. For more details see "GD32F20x User Manual"
Pins:
PD12 LED_BUILTIN # LCD backlight brightness control
Brightness can be controlled by :
int brightness = xx; where xx from 0 to 255
pinMode(PD12, OUTPUT);
analogWrite(PD12, brightness);
or
digitalwrite(PD12, HIGH); for 100% brightness
Board is supported by modified Adafruit_TFTLCD_16bit_GD32 (embedded into the platform, no installation needed). Adafruit_TFTLCD_16bit_GD32 library uses Adafruit GFX Library (This is the core graphics library for all Adafruit displays, providing a common set of graphics primitives (points, lines, circles, etc.). So you can easy migrate your sketches with Adafruit displays to this board.
Original library: Adafruit_TFTLCD_16bit_STM32
Install "Adafruit GFX" and "Adafruit BusIO" libraries from Arduino Library Manager. And use Adafruit_TFTLCD_16bit_GD32 library.
Example:
TFT35-E3-graphicstest.ino
The following pins are already configured in libraries and they can`t be used in sketches:
PE2 ------> FSMC_A23
PE7 ------> FSMC_D4
PE8 ------> FSMC_D5
PE9 ------> FSMC_D6
PE10 ------> FSMC_D7
PE11 ------> FSMC_D8
PE12 ------> FSMC_D9
PE13 ------> FSMC_D10
PE14 ------> FSMC_D11
PE15 ------> FSMC_D12
PD8 ------> FSMC_D13
PD9 ------> FSMC_D14
PD10 ------> FSMC_D15
PD14 ------> FSMC_D0
PD15 ------> FSMC_D1
PD0 ------> FSMC_D2
PD1 ------> FSMC_D3
PD4 ------> FSMC_NOE
PD5 ------> FSMC_NWE
PD7 ------> FSMC_NE1
Touchscreen is connected to XPT2046 chip via software SPI interface.
Install library SoftSPIB from Arduino Library Manager. Use library XPT2046_Touchscreen_SWSPI (fork of XPT2046_Touchscreen library by Paul Stoffregen https://github.com/PaulStoffregen/XPT2046_Touchscreen). This library is embedded into the platform, no additional installation needed.
Example:
TouchTest.ino
Pins: (can be used in other libraries or sketches if touchscreen is not used)
PC13 XPT2046_TPEN
PE3 XPT2046_MOSI
PE4 XPT2046_MISO
PE5 XPT2046_SCK
PE6 XPT2046_CS
Install library 'Adafruit_SPIFlash' from Arduino Library Manager ("SdFat_-_Adafruit_Fork" library will also be installed). SD card can work with standard Arduino library "SD" via default "SPI" interface.
Note: Card must be formatted in FAT16 or FAT32 filesystem. Use SDcard formatter from utilites SDCardFormatterv5_WinEN
Pins:
PC4 CARD DETECT PIN
PA4 SPI CS_PIN
PA5 SPI SCK_PIN
PA6 SPI MISO_PIN
PA7 SPI MOSI_PIN
Using SPI interface in Adafruit_SPIFlash library:
SdFat sd(&SPI);
#define SD_CS PA4
...
//some code
...
sd.begin(SD_CS, SD_SCK_MHZ(50));
Flash chip is connected via hardware SPI3 interface.
The chip is BoyaMicro BY25Q64AS 8MByte SPI flash. Use Adafruit_SPIFlash library which is embedded into this platform, no additional installation needed.
Pins:
PB6 PIN_SPI_SS
PB5 PIN_SPI_MOSI
PB4 PIN_SPI_MISO
PB3 PIN_SPI_SCK
Using SPI interface in Adafruit_SPIFlash library:
//define spi interface and flash transport
SPIClass mflashSPI(PB5, PB4, PB3);
Adafruit_FlashTransport_SPI flashTransport(PB6, &mflashSPI);
// now you can use flash
Adafruit_SPIFlash flash(&flashTransport);
Examples:
Pins:
PC8 Button
PA8 ENCA
PC9 ENCB
Example: encoder_test.ino
Core supports GD32 as a USB host, with FatFs support. Just use embedded FatFs library.
To use USB as default 'Serial' port:
- Select Tools -> USB Support -> USB Host
Example: FatFsTest.ino
Board has 2 NEOPIXEL RGB LEDs located under the rotary encoder's knob.
Pin:
PC7
Use embedded "Adafruit_NeoPixel" library, no additional installation needed. Define pin and number of neopixels.
// Which pin on the Arduino is connected to the NeoPixels?
#define PIN PC7 // On Trinket or Gemma, suggest changing this to 1
// How many NeoPixels are attached to the Arduino?
#define NUMPIXELS 4 // Popular NeoPixel ring size
Example: neopixel-simple.ino