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#include "usart.h"
static uint16_t usart_baudrate;
static uint16_t usart_baud_prescale;
void usart_init(uint16_t baudrate)
{
// enable RX and TX
UCSR0B |= _BV(RXEN0) | _BV(TXEN0);
// set 8 bit size char
UCSR0C |= _BV(UCSZ01) | _BV(UCSZ00);
// set baudrate
usart_baudrate = baudrate;
usart_baud_prescale = (F_CPU / (usart_baudrate * 16)) -1;
UBRR0L = usart_baud_prescale;
UBRR0H = usart_baud_prescale >> 8;
}
void usart_send_byte(uint8_t data)
{
while (!(UCSR0A & _BV(UDRE0)));
UDR0 = data;
}
void usart_send(uint8_t *data, size_t len)
{
uint8_t *p = data;
while (len--) {
usart_send_byte(*(p++));
}
}
void usart_print(char *str)
{
char *p = str;
size_t len = 0;
while (*p++ != '\0') {
len++;
}
usart_send((uint8_t *) str, len);
}
int usart_read_byte(uint8_t *byte)
{
uint16_t timeout = USART_TIMEOUT;
do {
if (UCSR0A & _BV(RXC0)) {
*byte = UDR0;
return 0;
}
} while (timeout--);
return -1;
}
uint8_t usart_read_byte_nt(void)
{
while ((UCSR0A & _BV(RXC0)) == 0);
return UDR0;
}
size_t usart_read(uint8_t *buffer, size_t len)
{
size_t read = 0;
uint8_t *p = buffer;
while (len--) {
if (usart_read_byte(p) == 0) {
p++;
read++;
}
}
return read;
}
int usart_read_line(uint8_t *buffer, size_t len)
{
uint8_t ch;
uint8_t *p = buffer;
size_t read = 0;
while (len--) {
if (usart_read_byte(&ch) != 0)
continue;
else
read++;
if (ch == '\n')
break;
else
*(p++) = ch;
}
if (ch != '\n')
return -1;
return 0;
}
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