Colony

/**

 * Determines a hexadecimal digit in ASCII code.

 *

 * @param value the value of the digit (0<=value<=15)

 * 

 * @return the hexadecimal digit in ASCII code, or '?'

 * if the input is invalid.

 **/

uint8_t hex_digit (uint8_t value)

{

    if (value>15) return '?';

    // Postcondition: 0<=x<=15

    return "0123456789ABCDEF"[value];

}

/**

 * Prints a fixed width hexadecimal representation of an unsigned

 * 16 bit integer in ASCII code to USB.

 * usb_init must be called before this function can be used.

 *

 * @param value the value to print

 * 

 * @see usb_init, usb_puti, usb_puts, usb_puth8, hex_digit

 **/

void usb_puth16 (uint16_t value)

{

    usb_putc (hex_digit((value >>12)&0xF));

    usb_putc (hex_digit((value >>8 )&0xF));

    usb_putc (hex_digit((value >>4 )&0xF));

    usb_putc (hex_digit( value      &0xF));

}

/**

 * Prints a fixed width hexadecimal representation of an unsigned

 * 8 bit integer in ASCII code to USB.

 * usb_init must be called before this function can be used.

 *

 * @param value the value to print

 * 

 * @see usb_init, usb_puti, usb_puts, usb_puth16, hex_digit

 **/

void usb_puth8(uint8_t value)

{

    usb_putc (hex_digit ((value)>>4 &0xF));

    usb_putc (hex_digit ( value     &0xF));

}