Save power by putting the module to sleep

lantern/main.c

@@ -10,23 +10,34 @@ This AVR library is distributed in the hope that it will be useful, but WITHOUT
 You should have received a copy of the GNU General Public License along with this AVR library. If not, see <https://www.gnu.org/licenses/>.
 */
 
-#include <dio.h>
-#include <sk9822.h>
-#include <rng.h>
 #include <animation.h>
-#include <display.h>
+#include <avr/interrupt.h>
 #include <avr/sleep.h>
+#include <dio.h>
+#include <display.h>
+#include <rng.h>
+#include <sk9822.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 
 #define FPS                 15
-#define FRAME_DELAY_MS      1000 / FPS
-// #define FRAME_DELAY_MS  1000
+#define TICKS_PER_SECOND    7812
+#define FPS_TIMEOUT         TICKS_PER_SECOND / FPS
 #define LIGHT_COUNT         3
 #define PULSE_OFF_COUNT     FPS * 5
 #define PULSE_ON_COUNT      5
 
+uint8_t status_light_value = 0;
+dio_t status_light = { .ddr = &DDRC, .port = &PORTC, .pin = &PINC, .addr = 7 };
+
+ISR(TIMER1_COMPA_vect) {
+    /*
+    status_light_value = !status_light_value;
+    dio_set(&status_light, status_light_value);
+    */
+}
+
 typedef enum {
     normal,
     spooky,
@@ -264,10 +275,27 @@ typedef struct {
     int timeout;
 } power_pulse_t;
 
+void setup_fps_timer(void) {
+    // WGM = 0100: CTC with OCR1nA top
+    // CS = 101: clock / 1024
+    TCCR1A = 0;
+    TCCR1B = _BV(3) | _BV(2) | _BV(0);
+
+    // Set the top for the counter
+    OCR1AH = FPS_TIMEOUT >> 8;
+    OCR1AL = FPS_TIMEOUT & 0xff;
+
+    // Enable compare on A match interrupt
+    TIMSK1 |= _BV(1);
+}
+
 int main(void) {
-    dio_t status_light = { .ddr = &DDRC, .port = &PORTC, .pin = &PINC, .addr = 7 };
     dio_set_direction(&status_light, LINE_OUT);
 
+    // Disable unneeded modules
+    PRR0 = _BV(7) | _BV(5) | _BV(2);
+    PRR1 = _BV(7) | _BV(4) | _BV(3) | _BV(0);
+
     dio_t power_pulse = { .ddr = &DDRF, .port = &PORTF, .pin = &PINF, .addr = 0 };
     dio_set_direction(&power_pulse, LINE_OUT);
 
@@ -306,12 +334,20 @@ int main(void) {
     lantern_step(&lantern, &display, &rng, colors);
     sk9822_send(&lights, colors, LIGHT_COUNT);
 
-    power_pulse_t timer = { .on = false, .timeout = PULSE_OFF_COUNT };
+    // power_pulse_t timer = { .on = false, .timeout = PULSE_OFF_COUNT };
 
+    setup_fps_timer();
+
+    set_sleep_mode(SLEEP_MODE_IDLE);
     while(1) {
         lantern_step(&lantern, &display, &rng, colors);
         sk9822_send(&lights, colors, LIGHT_COUNT);
 
+        sei();
+        sleep_mode();
+        cli();
+
+        /*
         if (timer.timeout > 0) {
             timer.timeout--;
         } else {
@@ -327,6 +363,7 @@ int main(void) {
         }
 
         _delay_ms(FRAME_DELAY_MS);
+        */
     }
 
     return 0;