To start using Waspmote USB library, an object from class 'WaspUSB' must be created. This object, called USB, is created inside the Waspmote USB library and it is public to all libraries. It is used through the guide to show how the Waspmote USB library works.
When creating this constructor, one variable is initialized. This variable specifies the number of the UART that USB is going to use (UART0 in this case).
Pre-Defined Constants
There are some constants defined in 'WaspUSB .h' related with the different kind of numbers that can be printed on the screen.
Initialization
Two functions have been created to open and close the UART used to communicate via USB.
Example of use:
{
USB.ON(); // Opens the UART at 115200 bps by default
USB.OFF(); // Closes the UART
}
Reading data
Two functions have been developed for reading data or checking if data is available in the UART. One more function has been developed to free the UART buffer.
Example of use:
{
int data_read=0;
if(USB.available())
{
// If data is available '1' is returned
data_read=USB.read(); // Reads data from UART0
}
USB.flush(); // Frees the UART buffer. All the data unread are lost.
}
Printing data
Some functions have been created to write data to the UART.
Example of use:
Print a character
{
char charac='a';
USB.print(charac); // Writes the char 'a' to the UART
USB.println(charac); // Writes the char 'a' to the UART adding an EOL
USB.println(); // Writes an EOL
}
Print a string
{
char string[] = "Hello";
USB.print(string); // Writes a string to the UART
USB.println(string); // Writes a string to the UART adding an EOL
}
Print uint8_t (1 byte)
{
uint8_t unsigned=3;
USB.print(unsigned); // Writes the number '3' to the UART
USB.println(unsigned); // Writes the number '3' to the UART adding an EOL
}
Print int (2 bytes)
{
int integer=54345;
USB.print(integer); // Writes the number '54345' to the UART
USB.println(integer); // Writes the number '54345' to the UART adding an EOL
}
Print long (4 bytes)
{
long long_int=1234567;
USB.print(long_int); //Writes the number '1234567' to the UART
USB.println(long_int); //Writes the number '1234567' to the UART adding an EOL
}
Print float (4 bytes)
{
float float_num=1.23456;
USB.print(float_num); //Writes the number '1.23456' to the UART
USB.println(float_num); //Writes the number '1.23456' to the UART adding an EOL
}
Print hexadecimal number (1 byte)
{
uint8_t num = 0x14;
USB.printHex(num); // Writes the number 0x14 in base 16
}
{
USB.println(78); // Writes 78 in integer format: \'78\'
USB.println(78, BIN); // Writes 78 in binary format: \'1001110\'
USB.println(78, OCT); // Writes 78 in octal format: \'116\'
USB.println(78, DEC); // Writes 78 in integer format: \'78\'
USB.println(78, HEX); // Writes 78 in hexadecimal format: \'4E\'
}
Print formatted data
{
int var1=0xABCD;
int var2=3.1416;
int var3=32767; //max signed int
int var4=32768; //overflows signed int range
long var5=2147483647; //max signed long int
long var6=2147483648; //overflows signed long range
unsigned long var7=4294967295; //max unsigned long
USB.printf(\"%s\n\", \"Hello world\"); // Writes "Hello World" with EOL
USB.printf(\"millis: %lu\n\",millis()); // Writes "millis: 356" with EOL
USB.printf(\"hexadecimal: %x\n\", var1); // Writes "hexadecimal: abcd" with EOL
USB.printf(\"decimal: %d\n\", var1); // Writes "decimal: -21555" with EOL
USB.printf(\"unsigned int: %u\n\", var1);// Writes "unsigned int: 43981" with EOL
USB.printf(\"float: %f\n\", var2); // It is not possible to print floats this way
USB.printf(\"int: %d\n\", var3); // Writes "int: 32767" with EOL
USB.printf(\"\'32768\' overflows: %d\n\", var4); // Writes "\'32768\' overflows: -32768"
USB.printf(\"signed long: %ld\n\", var5);// Writes "signed long: 2147483647" with EOL
USB.printf(\"\'2147483648\' overflows: %ld\n\", var6);Writes "\'2147483648\' overflows: -2147483648"
USB.printf(\"unsigned long: %lu\n\", var7); // Writes "unsigned long: 4294967295"
}
