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#include "ace.h"
#include <avr/interrupt.h>
typedef struct {
uint8_t buffer[SERIAL_BUFFER_SIZE];
volatile uint16_t head;
volatile uint16_t tail;
} ring_buffer;
static ring_buffer tx_buffer0 = {{0}, 0, 0};
static framer framer0;
static arq arq0;
static uint32_t max_ticks0;
static uint32_t ticks0;
//initialize UART
static void init_s0(uint32_t baud) {
UCSR0A |= (1 << U2X0); //enable double speed transmission
uint16_t baud_setting = (F_CPU / 4 / baud - 1) / 2;
UBRR0H = baud_setting >> 8;
UBRR0L = baud_setting;
UCSR0B |= (1 << RXEN0) | (1 << TXEN0) | (1 << RXCIE0); // defaults to 8-bit, no parity, 1 stop bit
UCSR0B &= ~(1 << UDRIE0) | (1 << TXEN0) | (1 << RXCIE0);
}
static void send_to_s0(uint8_t byte) {
uint16_t i = (tx_buffer0.head + 1) % SERIAL_BUFFER_SIZE;
// If the output buffer is full, there's nothing for it other than to
// wait for the interrupt handler to empty it a bit
if (i == tx_buffer0.tail) return;
//while (i == tx_buffer0.tail) {};
tx_buffer0.buffer[tx_buffer0.head] = byte;
tx_buffer0.head = i;
//enable data register empty interrupt
UCSR0B |= (1 << UDRIE0);
}
static void send_to_framer0(int16_t size, const uint8_t* const data) {
send_frame(&framer0, size, data);
}
static void receive_from_framer0(int16_t size, uint8_t* data) {
receive_frame(&arq0, size, data);
}
//called when byte is received
ISR(USART0_RX_vect) {
uint8_t c = UDR0;
receive_byte(&framer0, c);
}
//called when data register is empty
ISR(USART0_UDRE_vect) {
if (tx_buffer0.head == tx_buffer0.tail) {
UCSR0B &= ~(1 << UDRIE0); //buffer empty, disable interruot
} else {
uint8_t c = tx_buffer0.buffer[tx_buffer0.tail];
tx_buffer0.tail = (tx_buffer0.tail + 1) % SERIAL_BUFFER_SIZE;
UDR0 = c; //write next byte
}
}
//initialize timer
static void init_t0(uint32_t ticks) {
cli();
TCCR1A = 0;
TCCR1B = 0;
TCCR1B |= (1 << WGM12); // turn on CTC mode:
TCCR1B |= (1 << CS11); // set CS31 for 64 prescaler
// set compare match register to desired timer count:
OCR1A = F_CPU / 1000 / 64; // should be 250 for F_CPU=16Mhz and f = 1000Hz
sei();
//the timer should now interrupt every ms
max_ticks0 = ticks;
ticks0 = 0;
}
inline static void start_t0() {
TIMSK1 |= (1 << OCIE1A);
}
inline static void stop_t0() {
TIMSK1 &= ~(1 << OCIE1A);
}
ISR(TIMER1_COMPA_vect) {
ticks0 += 1;
if (ticks0 > max_ticks0) {
timeout(&arq0);
ticks0 = 0;
}
}
void init_ace0(uint32_t baud, uint32_t extra_time) {
init_s0(baud);
init_framer(&framer0);
init_arq(&arq0);
framer0.sender = send_to_s0;
arq0.sender = send_to_framer0;
framer0.receiver = receive_from_framer0;
arq0.event_handler = ace_event0;
uint32_t bits = (MAX_FRAME_SIZE + 3) * 8 * 2;
uint32_t tx_time = bits * 1000 / baud; // transmission time in milliseconds
init_t0(tx_time + extra_time);
arq0.start_timer = start_t0;
arq0.stop_timer = stop_t0;
}
void ace_send0(uint8_t size, const uint8_t* const message) {
send_message(&arq0, size, message);
}
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