23 #define CDCACM_BUFFER 64
volatile uint8_t cdcacm_received
how many bytes available in the received buffer since last read
char cdcacm_getchar(void)
get character received over USB (blocking)
void cdcacm_putchar(char c)
send character over USB (non-blocking)
void cdcacm_setup(void)
setup USB CDC ACM peripheral