7seg/fw/led.c

70 lines
2.3 KiB
C

/* Megumin LED display firmware
* Copyright (C) 2018 Sebastian Götte <code@jaseg.net>
*
* 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 "global.h"
#include "led.h"
/* Status LED control */
#define LED_STRETCHING_MS 50
static volatile int error_led_timeout = 0;
static volatile int comm_led_timeout = 0;
static volatile int id_led_timeout = 0;
volatile int led_state = 0;
void trigger_error_led() {
error_led_timeout = LED_STRETCHING_MS;
}
void trigger_comm_led() {
comm_led_timeout = LED_STRETCHING_MS;
}
void trigger_id_led() {
id_led_timeout = LED_STRETCHING_MS;
}
void led_task() {
static int last_time = 0;
/* Crude LED logic. The comm, id and error LEDs each have a timeout counter
* that is reset to the LED_STRETCHING_MS constant on an event (either a
* frame received correctly or some uart, framing or protocol error). These
* timeout counters count down in milliseconds and the LEDs are set while
* they are non-zero. This means a train of several very brief events will
* make the LED lit permanently.
*/
int time_now = sys_time; /* Latch sys_time here to avoid race conditions */
if (last_time != time_now) {
int diff = (time_now - last_time);
error_led_timeout -= diff;
if (error_led_timeout < 0)
error_led_timeout = 0;
comm_led_timeout -= diff;
if (comm_led_timeout < 0)
comm_led_timeout = 0;
id_led_timeout -= diff;
if (id_led_timeout < 0)
id_led_timeout = 0;
led_state = (led_state & ~7) | (!!id_led_timeout)<<2 | (!!error_led_timeout)<<1 | (!!comm_led_timeout)<<0;
last_time = time_now;
}
}