The device shows up on your phone as a bluetooth device called "M5StickC", and once you've connected from your device you can use an app like Serial Bluetooth Terminal communicate with your device.
Messages coming from USB serial port are printed as white text and messages coming from bluetooth are printed as blue text.
#include "bluetoothserial.h"
#include "m5stickc.h"
// M5StickC screen parameters
#define TEXT_HEIGHT 16 // Height of text to be printed and scrolled
#define TOP_FIXED_AREA 14 // Number of lines in top fixed area (lines counted from top of screen)
#define BOTTOM_FIXED_AREA 0 // Number of lines in bottom fixed area (lines counted from bottom of screen)
#define YMAX 80 // Bottom of screen area
#define XMAX 160 // Bottom of screen area
uint16_t yStart = 0; // The initial y coordinate of the top of the scrolling area
uint16_t yArea = YMAX-TOP_FIXED_AREA-BOTTOM_FIXED_AREA; // yArea must be a integral multiple of TEXT_HEIGHT
uint16_t yDraw = 0; // The initial y coordinate of the top of the bottom text line
uint16_t xPos = 0; // Keep track of the drawing x coordinate
byte data = 0;
int blank[19]; // We keep all the strings pixel lengths to optimise the speed of the top line blanking
BluetoothSerial SerialBT;
void setup() {
// Setup the TFT display
M5.begin();
M5.Lcd.setRotation(3); // Must be setRotation(0) for this sketch to work correctly
M5.Lcd.fillScreen(TFT_BLACK);
M5.Lcd.setTextColor(TFT_WHITE, TFT_BLUE);
M5.Lcd.fillRect(0, 0, XMAX, TEXT_HEIGHT, TFT_BLUE);
M5.Lcd.drawCentreString("Serial Term - 115200", XMAX/2, 0, 2);
M5.Lcd.setTextColor(TFT_WHITE, TFT_BLACK); // Change colour for scrolling zone text
setupScrollArea(TOP_FIXED_AREA, BOTTOM_FIXED_AREA); // Setup scroll area
for (byte i = 0; i<18; i++) blank[i]=0; // Zero the array
Serial.begin(115200); // Initialise the serial ports
SerialBT.begin("M5StickC"); // Bluetooth device name
Serial.println("\n# Bluetooth started #\n"); // Let the user know via usb serial port the device is ready
}
void loop() {
// Check the Serial buffer for a new message
while(Serial.available()) {
data = Serial.read(); // Read the character from the serial port
SerialBT.write(data); // Write the message to the Bluetooth serial port
M5.Lcd.setTextColor(TFT_WHITE, TFT_BLACK);
writeToScreen(data); // Also write to the M5StickC screen
}
// Check the bluetooth buffer for a new message
while(SerialBT.available()) {
data = SerialBT.read(); // Read the character from the bluetooth port
Serial.write(data); // Write the message to the serial port
M5.Lcd.setTextColor(TFT_BLUE, TFT_BLACK);
writeToScreen(data); // Also write to the M5StickC screen
}
delay(20);
}
void writeToScreen(byte data) {
// If it is a CR or we are near end of line then scroll one line
if (data == '\r' || xPos > XMAX) {
xPos = 0;
yDraw = scroll_line(); // It can take 13ms to scroll and blank 16 pixel lines
}
if (data > 31 && data < 128) {
xPos += M5.Lcd.drawChar(data,xPos,yDraw,2);
}
}
/**
* Scroll the display one text line
*/
int scroll_line() {
// Store the old yStart, this is where we draw the next line
int yTemp = yStart;
// Use the record of line lengths to optimise the rectangle size we need to erase the top line
M5.Lcd.fillRect(0,yStart,XMAX,TEXT_HEIGHT,TFT_BLACK);
// Change the top of the scroll area
yStart += TEXT_HEIGHT;
// The value must wrap around as the screen memory is a circular buffer
if (yStart >= YMAX)
yStart = 0;
// Now we can scroll the display
scrollAddress(yStart);
return yTemp;
}
/**
* Setup the vertical scrolling start address pointer
*/
void scrollAddress(uint16_t vsp) {
M5.Lcd.writecommand(ST7735_VSCRDEF); // Vertical scrolling pointer
M5.Lcd.writedata(vsp>>8);
M5.Lcd.writedata(vsp);
}
/**
* Setup a portion of the screen for vertical scrolling
* We are using a hardware feature of the display, so we can only scroll in portrait orientation
*/
void setupScrollArea(uint16_t tfa, uint16_t bfa) {
M5.Lcd.writecommand(ST7735_VSCRDEF); // Vertical scroll definition
M5.Lcd.writedata(tfa >> 8); // Top Fixed Area line count
M5.Lcd.writedata(tfa);
M5.Lcd.writedata((YMAX-tfa-bfa)>>8); // Vertical Scrolling Area line count
M5.Lcd.writedata(YMAX-tfa-bfa);
M5.Lcd.writedata(bfa >> 8); // Bottom Fixed Area line count
M5.Lcd.writedata(bfa);
}
