forked from labitat/blipduino
/
blipduino.c
173 lines (139 loc) · 2.88 KB
/
blipduino.c
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/*
* This file is part of blipduino.
*
* blipduino 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.
*
* blipduino 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 blipduino. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdint.h>
#include <arduino/pins.h>
#include <arduino/sleep.h>
#include <arduino/serial.h>
#include <arduino/timer2.h>
#include <arduino/adc.h>
#define BOUND_LOW 10
#define BOUND_HIGH 350
static volatile uint8_t new_value;
static volatile struct {
char *str;
uint8_t printing;
} output;
serial_interrupt_dre()
{
char *str = output.str;
uint8_t c = *str;
if (c == '\0') {
serial_interrupt_dre_disable();
output.printing = 0;
} else {
serial_write(c);
output.str = str + 1;
}
}
static void
serial_puts(char *str)
{
again:
cli();
if (output.printing) {
sleep_enable();
sei();
sleep_cpu();
sleep_disable();
goto again;
}
sei();
output.str = str;
output.printing = 1;
serial_interrupt_dre_enable();
}
static char *
sprint_uint16_b10(char *p, uint16_t n)
{
if (n >= 10000)
*p++ = '0' + (n / 10000);
if (n >= 1000)
*p++ = '0' + (n / 1000) % 10;
if (n >= 100)
*p++ = '0' + (n / 100) % 10;
if (n >= 10)
*p++ = '0' + (n / 10) % 10;
*p++ = '0' + n % 10;
return p;
}
static volatile uint16_t time;
static char buf[16] __attribute__ ((section (".noinit")));
timer2_interrupt_a()
{
time++;
}
adc_interrupt()
{
new_value = 1;
}
int __attribute__((noreturn))
main()
{
uint8_t state = 0;
serial_baud_9600();
serial_mode_8e1();
serial_transmitter_enable();
sleep_mode_idle();
pin13_mode_output();
pin13_low();
/* setup timer2 to trigger interrupt a
* once every millisecond
* 128 * (124 + 1) / 16MHz = 1ms */
timer2_mode_ctc();
timer2_clock_d128();
timer2_compare_a_set(124);
timer2_interrupt_a_enable();
adc_reference_internal_5v();
adc_pin_select(5);
adc_clock_d128();
adc_trigger_freerunning();
adc_trigger_enable();
adc_interrupt_enable();
adc_enable();
sei();
while (1) {
uint16_t value;
cli();
if (!new_value) {
sleep_enable();
sei();
sleep_cpu();
sleep_disable();
continue;
}
sei();
value = adc_data();
new_value = 0;
if (state && value < BOUND_LOW) {
uint16_t now = time;
char *p;
timer2_clock_reset();
time = 0;
pin13_low();
p = sprint_uint16_b10(buf, now);
*p++ = '\n';
*p = '\0';
serial_puts(buf);
state = 0;
continue;
}
if (value > BOUND_HIGH) {
pin13_high();
state = 1;
}
}
}