Reading and Writing Text over USB A Colony Project Tutorial

2 Differences between Windows and Linux On Windows, the robot is connected to a com port, usually com1 – com4 – This can be found in the device manager On Linux, the robot is connected to /dev/ttyUSB0 or higher numbers – Guess the number until you get it right

Tera Term Serial input and output program Lets you view stuff that the robot has printed to USB Can also write responses to robot 3

Open a Serial Connection In Tera Term, use Setup->Serial Port to start a session Use File->Disconnect to end a session The Baud rate should be

Basic USB Write Functions usb_putc(char c) – ex: usb_putc(‘a’); usb_puts(char* s) – ex: usb_puts(“testing”); usb_puti(int i) – ex: usb_puti(12); 5

Advanced USB Write Functions usb_puth8(int i) – print 8 bit hex value – ex: usb_puth8(0xA6); usb_puth16(int i) – also named usb_puth(int i) – print 16 bit hex value – ex: usb_puth16(0x5D2F); 6

USB Read Functions int usb_getc() – returns a character – ex: c = usb_getc(); int usb_getc_nb() – nonblocking form of usb_getc – returns -1 if no character present in input buffer – ex: c = usb_getc_nb(); 7

Example – test_usb.c usb_init(); usb_puts("usb turned on, test starting:\r\n"); usb_puts("\r\n\n"); delay_ms(1000); // print some values to usb usb_puts("Testing...\r\n"); usb_puti(1); usb_putc(','); usb_putc(' '); usb_puti(2); usb_putc(','); usb_putc(' '); usb_puti(3); usb_putc('\r'); usb_putc('\n'); usb_puth8(0x2A); usb_putc(','); usb_putc(' '); usb_puth16(0xF4); usb_putc(','); usb_putc(' '); usb_puth(0xC8E1); usb_putc('\r'); usb_putc('\n'); usb_puts("enter an 'a':"); if (usb_getc() == 'a') usb_puts("\r\ngetc() works\r\n"); else usb_puts("\r\ngetc() fails\r\n"); usb_puts("done.\r\n\r\n"); 8