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/*
* Copyright 2012 (C) Christian Franke <nobody at nowhere dot ws>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with This program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <avr/interrupt.h>
#include <avr/io.h>
#include <stdint.h>
#include <string.h>
char output_buffer[512];
uint16_t output_offset = 0;
uint16_t output_end = 0;
char input_buffer[512];
uint16_t input_end = 0;
volatile uint16_t value_red = 3072;
volatile uint16_t value_green = 2048;
volatile uint16_t value_blue = 1024;
uint8_t verbose = 0;
static void send(const char *buffer, uint16_t len)
{
cli();
if (sizeof(output_buffer) - output_end < len) {
memmove(output_buffer, output_buffer + output_offset, output_end -
output_offset);
output_end -= output_offset;
output_offset = 0;
}
uint16_t size = len;
if (size > sizeof(output_buffer) - output_end)
size = sizeof(output_buffer) - output_end;
memcpy(&output_buffer[output_end], buffer, size);
uint8_t send_needed = output_end == output_offset;
output_end += size;
sei();
if (send_needed) {
output_offset++;
UDR1 = output_buffer[output_offset - 1];
}
}
ISR(USART1_TX_vect)
{
if (output_end == output_offset)
return;
UDR1 = output_buffer[output_offset];
output_offset++;
}
static void send_confusion(void)
{
send("?\r\n", 3);
}
static void send_success(void)
{
if (verbose) {
send(":)\r\n", 4);
}
}
static uint8_t parse_hex(char *buffer, uint8_t *target)
{
if (buffer[0] >= '0' && buffer[0] <= '9') {
*target = 16 * (buffer[0] - '0');
} else if (buffer[0] >= 'A' && buffer[0] <= 'F') {
*target = 16 * (buffer[0] - 'A' + 10);
} else if (buffer[0] >= 'a' && buffer[0] <= 'f') {
*target = 16 * (buffer[0] - 'a' + 10);
} else {
return 1;
}
if (buffer[1] >= '0' && buffer[1] <= '9') {
*target += buffer[1] - '0';
} else if (buffer[1] >= 'A' && buffer[1] <= 'F') {
*target += buffer[1] - 'A' + 10;
} else if (buffer[1] >= 'a' && buffer[1] <= 'f') {
*target += buffer[1] - 'a' + 10;
} else {
return 1;
}
return 0;
}
static void handle_immediate(void)
{
if (input_end < sizeof("irrggbb\r") - 1) {
send_confusion();
return;
}
uint8_t new_red, new_blue, new_green;
if (parse_hex(&input_buffer[1], &new_red)
|| parse_hex(&input_buffer[3], &new_green)
|| parse_hex(&input_buffer[5], &new_blue)) {
send_confusion();
return;
}
value_red = (uint16_t)new_red << 4;
value_green = (uint16_t)new_green << 4;
value_blue = (uint16_t)new_blue << 4;
send_success();
}
static void parse_buffer(void)
{
switch (input_buffer[input_end - 1]) {
case '\r':
case '\n':
if (verbose)
send("\r\n", 2);
break;
default:
if (verbose)
send(input_buffer + input_end - 1, 1);
return;
}
switch (input_buffer[0]) {
case 'i':
case 'I':
handle_immediate();
break;
case 'q':
case 'Q':
verbose = 1 - verbose;
send_success();
break;
default:
send_confusion();
}
input_end = 0;
}
ISR(USART1_RX_vect)
{
if (input_end == sizeof(input_buffer))
input_end = 0;
input_buffer[input_end++] = UDR1;
parse_buffer();
}
int main(void)
{
UBRR1 = 4; /* Set baud rate to 230400 */
UCSR1A = 0x00;
UCSR1B = (1 << RXCIE1) | (1 << TXCIE1) | (1 << RXEN1) | (1 << TXEN1);
UCSR1C = (1 << UCSZ11) | (1 << UCSZ10);
sei(); /* Enable interrupts */
PORTA = 0x00;
DDRA = (1 << PA0) | (1 << PA1) | (1 << PA2);
for (;;) {
if (value_red)
PORTA |= (1 << PA0);
if (value_green)
PORTA |= (1 << PA1);
if (value_blue)
PORTA |= (1 << PA2);
for (uint16_t i = 0; i < 4096; i++) {
if (value_red < i)
PORTA &= ~(1 << PA0);
if (value_green < i)
PORTA &= ~(1 << PA1);
if (value_blue < i)
PORTA &= ~(1 << PA2);
}
}
}
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