main.cpp

00001 /* Testing the overflow of Timer
00002 LCD on I2C bus, PCF8574
00003  */
00004 #include "mbed.h"
00005 #include "TextLCD.h"
00006 
00007 Timer t;
00008 
00009 I2C i2c_lcd(I2C_SDA,I2C_SCL); // SDA, SCL
00010 
00011 TextLCD_I2C lcd(&i2c_lcd, 0x40, TextLCD::LCD16x2); // I2C bus, PCF8574 Slaveaddress, LCD Type
00012 
00013 // Trick to change baudrate of stdout, SFord
00014 void baud(int baudrate)
00015 {
00016     Serial s(USBTX, USBRX);
00017     s.baud(baudrate);
00018 }
00019 
00020 int main()
00021 {
00022     uint32_t    Millis, LastMillis;
00023     baud(921600);   // see function above
00024     i2c_lcd.frequency(400000);  // 400KHz
00025     lcd.setCursor(lcd.CurOff_BlkOff); // Cursor off, Blink off
00026     lcd.cls();
00027     lcd.setBacklight(TextLCD::LightOn);
00028     lcd.locate(0,0);  // Goto beginning of line = second par.
00029     lcd.printf("Testing Timer...\n");
00030     lcd.locate(0,1);  // Goto beginning of line = second par.
00031     lcd.printf("...us overflow  \n");
00032     printf("\nTesting Timer us overflow..\n");
00033 
00034     t.reset();
00035     t.start();
00036 
00037 #define TIMER_MASK (0x1000uL - 1)
00038 
00039     Millis = t.read_ms() & TIMER_MASK;
00040     lcd.locate(0,1);  // Goto beginning of line = second par.
00041     lcd.printf("Start M: %08d",Millis);
00042 
00043     do {
00044         LastMillis = Millis;
00045         Millis = t.read_ms() & TIMER_MASK;
00046     } while(LastMillis <= Millis);
00047 
00048     lcd.locate(0,0);  // Goto beginning of line = second par.
00049     lcd.printf("Last M: %08d",LastMillis);
00050     lcd.locate(0,1);
00051     lcd.printf("Act. M: %08d",Millis);
00052 
00053     printf("Last Millis: %08d\n",LastMillis);
00054     printf("Act. Millis: %08d\n",Millis);
00055 }