This example show how Seeeduino XIAO display on OLED screen, with ssd1306 driver using I2C interface, using ssd1306 library.
Connection between XIAO and OLED (ssd1306)
XIAO OLED (ssd1306 I2C)
3V3 VCC
GND GND
SDA SDA
SCL SCL
Make sure Seeed SAMD Boards is installed in Boards Manager, refer to the post Seeeduino XIAO for Install Seeeduino XIAO board to Arduino IDE.
HC-08 is a Bluetooth 4.0 low energy module. It provide TTL Serial interface. If we want to access it using PC, normal a USB-to-Serial adapter is used.
In this exercise, Seeeduino XIAO is programmed as a USB-to-Serial bridge to read/write HC-08 from Raspberry Pi using Arduino IDE's Serial Monitor.
Connection between Seeeduino XIAO and HC-08
XIAO HC-08
=====================
3V3 VCC
GND GND
TX RX
RX TX
For the code, simple foreward date from SerialUSB to Serial1, and foreward Serial1 to SerialUSB.
X_USBbridge.ino
/*
Xiao act as a bridge between USB and Serial device
It's assumed the device is running 3V3
Connection
Xiao Rx - device Tx
Xiao Tx - device Rx
XIAO GND - device GND
XIAO 3V3 - device VCC
*/
void setup()
{
pinMode(LED_BUILTIN, OUTPUT);
delay(1000);
SerialUSB.begin(9600);
Serial1.begin(9600);
//wait serial ports to device
//while(SerialUSB);
while(!Serial1);
//Blink the LED 3 times to indicate program started
for(int i=0; i<3; i++){
digitalWrite(LED_BUILTIN, HIGH);
delay(500);
digitalWrite(LED_BUILTIN, LOW);
delay(500);
}
}
void loop()
{
if(SerialUSB.available() > 0){
Serial1.write(SerialUSB.read());
}
if(Serial1.available() > 0){
SerialUSB.write(Serial1.read());
}
}
This video show how it work.
Before HC-08 connected (LED blinking), You can read/write HC-08 status with AT Command.
After HC-08 connected with test app on Android phone (LED on), you can send/receive text to/from the app.
To know where/how to download datasheet (with AT Command Set) and test app for HC-08, read the post "HC-08 Bluetooth Module (BLE 4.0)".
To install Seeeduino XIAO board to Arduino IDE, read the post "Seeeduino XIAO".
X_USBbridge_115200.ino
/*
Xiao act as a bridge between USB and Serial device
It's assumed the device is running 3V3
Connection
Xiao Rx - device Tx
Xiao Tx - device Rx
XIAO GND - device GND
XIAO 3V3 - device VCC
*/
void setup()
{
pinMode(LED_BUILTIN, OUTPUT);
delay(1000);
SerialUSB.begin(115200);
Serial1.begin(115200);
//wait serial ports to device
//while(SerialUSB);
while(!Serial1);
//Blink the LED 3 times to indicate program started
for(int i=0; i<3; i++){
digitalWrite(LED_BUILTIN, HIGH);
delay(500);
digitalWrite(LED_BUILTIN, LOW);
delay(500);
}
}
void loop()
{
if(SerialUSB.available() > 0){
Serial1.write(SerialUSB.read());
}
if(Serial1.available() > 0){
SerialUSB.write(Serial1.read());
}
}
The Seeeduino XIAO is a tiny microcontroller board with powerful cpu SAMD21G18, ARM® Cortex®-M0+ 32bit 48MHz microcontroller with 256KB Flash,32KB SRAM.
Seeeduino XIAO has 14 GPIO PINs, which can be used for 11 digital interfaces, 11 mock interfaces, 10 PWM interfaces (d1-d10), 1 DAC output pin D0, 1 SWD pad interface, 1 I2C interface, 1 SPI interface, 1 UART interface, Serial communication indicator (T/R), Blink light (L). The colors of LEDs(Power,L,RX,TX) are green, yellow, blue and blue. Moreover, Seeeduino XIAO has a Type-C interface which can supply power and download code. There are two reset pad, you can short connect them to reset the board.
Pinout:
HC-08 is a Bluetooth 4.0 low energy module, it can easily connect to iOS 5 and Android 4.3 or above by using a serial terminal app. You can use the Bluetooth communication up to 87 yards (80 meters) with this Bluetooth BLE module. It also runs on a 2.4GHz frequency. The chipset is CC2540 with 256K Byte space. You can change the role and serial baud rate and it supports AT commands for configuration.
It is very small in size, 1.1 x 0.5 in (26.9 x 13mm). The PCB thickness is 0.03 (0.7mm). Half-cut holes run along the lengths of the board, so it’s very easy to embed into your own project. It also has Tx and Rx 2.54 pin out, from which you can do a quick function test. Included are 90-degree male header pins.
HC-08 is a relatively new module made by an experienced Bluetooth design and manufacturing supplier in China. It’s mass produced and therefore well-tested. It can be incorporated into products or projects without worrying about being able to get it again. It’s already widely used in many Bluetooth projects.
Product page: http://www.hc01.com/products/6 (in Chinese)
It's a 0.96 inch 128x64 OLED displays with ssd1306 driver using I2C interface. This example show how to display text on it with pyboard using MicroPython ssd1306 library.
Connection between pyboard and OLED:
pyboard 3V3 connected to ssd1306 VCC
pyboard GND connected to ssd1306 GND
pyboard X12 connected to ssd1306 SCL
pyboard X11 connected to ssd1306 SDA
Download the MicroPython ssd1306 library HERE, ans save it to pyboard flash.
MicroPython script, pyb_i2c_ssd1306.py:
# Download ssd1306
# https://github.com/micropython/micropython/blob/master/drivers/display/ssd1306.py
# and save to pyboard flash
import ssd1306
import machine
import time
WIDTH = const(128)
HEIGHT = const(64)
ssd1306_scl = machine.Pin('X12', machine.Pin.OUT_PP)
ssd1306_sda = machine.Pin('X11', machine.Pin.OUT_PP)
i2c_ssd1306 = machine.I2C(scl=ssd1306_scl, sda=ssd1306_sda)
print(i2c_ssd1306.scan())
oled = ssd1306.SSD1306_I2C(WIDTH, HEIGHT, i2c_ssd1306)
oled.fill(0)
oled.text("MicroPython", 0, 0)
oled.text("OLED(ssd1306)", 0, 10)
oled.text("pyboard", 0, 20)
oled.show()
while True:
time.sleep(1)
oled.invert(1)
time.sleep(1)
oled.invert(0)
It's a MicroPython exercise running on pyboard, to scan I2C address of attached I2C device. Actually, the I2C device used is a OLED with I2C interface ssd1306 in next exercise.
i2c_scan.py
#I2C SCL connected to pyboard X12
#I2C SDA connected to pyboard X11
import machine
i2c_scl = machine.Pin('X12', machine.Pin.OUT_PP)
i2c_sda = machine.Pin('X11', machine.Pin.OUT_PP)
i2c = machine.I2C(scl=i2c_scl, sda=i2c_sda)
print(i2c.scan())
It's a modified version of MicroPython pyboard, PYBv1.1, with extra modification:
- BOOT0 button for enter DFU mode, such that you no need to use a wire to connect P1 and 3V3.
- SWD connetor
- PWR LED
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| MicroPython firmware updated |
SIPEED Maix Amigo is an all-in-one programmable AIoT development kit that can be used for AI and IoT learning. It has a built-in RV64GC RISC-V 64-bit 400Mhz dual-core high-performance processor with 8M on-chip SRAM and 16MiB FLASH storage. It is equipped with 2 cameras, TF card slot, user buttons, TFT capacitive touch screen, lithium battery, speaker, microphone, 2 USB ports, and an expansion interface.
Related links:
- Official MaixPy Documentation website: https://maixpy.sipeed.com/
- Download site: https://dl.sipeed.com/
- Sipeed programming guide: https://wiki.sipeed.com/
- Seeed Studio's Sipeed Maix Amigo page - Sipeed Maix Amigo - All-in-One AIoT Development Platform Based on RV64GC (RISC-V)