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serial.c
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serial.c
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#include "globals.h"
#include "serial.h"
#include "flash.h"
#include "commands.h"
#include <avr/interrupt.h>
#include <util/delay.h>
#define SOH 1
#define EOT 4
#define ACK 6
#define NAK 21
#define CAN 24
typedef enum {LOW, HIGH} lowhigh_t;
volatile char serial_in[64];
char serial_out[132];
volatile uint8_t serial_in_ctr;
volatile uint8_t serial_out_ctr;
static uint8_t packet_number = 1;
static lowhigh_t lowhigh;
static void prepare_packet(void);
inline void usart_init(void) {
UBRR0 = BAUD_VALUE;
UCSR0C = _BV(UCSZ00) | _BV(UCSZ01); // 8-bit, 1 stop bit, no parity
UCSR0B = _BV(TXEN0) | _BV(TXCIE0) | _BV(RXEN0) | _BV(RXCIE0); // Turn on TX and RX and their interrupts
//UCSR0A = _BV(U2X0); // Double serial clock
flag_xmodem_sending = flag_xmodem_finalizing = flag_xmodem_next_packet = false;
}
void usart_send_next_byte(void) {
bool_t length_ok = serial_out_ctr < 132;
bool_t notnull = serial_out[serial_out_ctr] != '\0';
if (length_ok && ((flag_xmodem_sending && !flag_xmodem_finalizing) || notnull)) {
while (!(UCSR0A & _BV(UDRE0))); // Ensure empty transmit buffer
UDR0 = serial_out[serial_out_ctr];
serial_out_ctr++;
} else {
flag_serial_sending = false;
if (flag_xmodem_finalizing) {
flash_scan();
flag_xmodem_sending = false;
flag_xmodem_finalizing = false;
}
}
}
void usart_dostuff() {
if (flag_command_ready)
handle_command();
if (flag_read_flash) {
bool_t verified = false;
while (!verified) {
flash_read(flash_addr);
verified = flash_verify(flash_addr);
}
while (!verified) {
_delay_ms(25);
flash_read(flash_addr);
verified = flash_verify(flash_addr);
}
flash_addr++;
flag_read_flash = false;
}
if (flag_xmodem_next_packet) {
prepare_packet();
usart_send();
}
}
static void prepare_packet(void) {
uint8_t start = 0;
if (lowhigh == HIGH) {
start = 128;
}
if (flash_buf[2] == 0xFF || flash_full()) {
serial_out[0] = EOT;
serial_out[1] = '\0';
} else {
int i;
uint8_t sum = 0;
serial_out[0] = SOH;
serial_out[1] = packet_number;
serial_out[2] = ~packet_number;
packet_number++;
for(i=0; i<128; i++) {
serial_out[i+3] = flash_buf[start+i];
sum += flash_buf[start+i];
}
serial_out[131] = sum;
if (lowhigh == LOW) {
lowhigh = HIGH;
} else {
lowhigh = LOW;
flag_read_flash = true;
}
}
flag_xmodem_next_packet = false;
}
void usart_reset_output(void) {
int i;
for(i=0; i<132; i++)
serial_out[i] = 0;
}
ISR(USART_TX_vect) {
usart_send_next_byte();
}
ISR(USART_RX_vect) {
char chr = UDR0;
//flag_user_active = true;
//last_activity = clock_ticks;
if (flag_xmodem_sending) {
if (chr == NAK) {
if (serial_out[0] == EOT) {
flag_xmodem_finalizing = true;
}
serial_out[0] = EOT;
serial_out[1] = '\0';
usart_send();
} else if (chr == ACK) {
if (flash_buf[2] == 0xFF) {
//if (packet_number > 1) {
serial_out[0] = EOT;
serial_out[1] = '\0';
usart_send();
} else {
flag_xmodem_next_packet = true;
}
} else if (chr == CAN) {
flag_xmodem_sending = false;
flag_xmodem_finalizing = false;
flash_scan();
}
} else {
if (chr == '\r' || chr == '\n') {
flag_command_ready = true;
} else if (chr == NAK) {
flag_xmodem_next_packet = true;
flag_xmodem_sending = true;
flag_read_flash = true;
flag_xmodem_finalizing = false;
flash_addr = 0;
lowhigh = LOW;
packet_number = 1;
} else if (chr == CAN || chr == ACK) {
// Ignore
} else {
while (!(UCSR0A & _BV(UDRE0))); // Ensure empty transmit buffer
if (chr == 8) { // backspace
if (serial_in_ctr > 0) {
serial_in_ctr--;
UDR0 = chr; // echo
while (!(UCSR0A & _BV(UDRE0))); // Ensure empty transmit buffer
UDR0 = ' ';
while (!(UCSR0A & _BV(UDRE0))); // Ensure empty transmit buffer
UDR0 = 8;
}
} else if (serial_in_ctr < 63) {
UDR0 = chr; // echo
serial_in[serial_in_ctr] = chr;
serial_in_ctr++;
} else {
UDR0 = '*';
}
}
}
}