Ring buffer fixes and spark time compute

STM32/CM7/Core/Src/tasks/crank.c

@@ -8,6 +8,7 @@
 #include "main.h"
 #include "ring_buffer.h"
 #include "tasks.h"
+#include <stdint.h>
 
 void crankHandler(void *argument) {
   for (;;) {
@@ -60,6 +61,13 @@ void crankHandler(void *argument) {
     if (state_g.crank_state == CYCLE_COMPRESSION &&
         state_g.sync_state == SYNC_OK) {
       DEBUG_LOG("Spark schedule reached, congrats\n\r");
+      uint32_t t_now = ringBufferRead(&state_g.crank_RB, 0);
+      uint32_t t_prev = ringBufferRead(&state_g.crank_RB, 1);
+
+      uint32_t d1a = t_now - t_prev;
+      // TODO: Map interpolation rather than SPARK_ADVANCE CONSTANT
+      uint32_t d_spark = d1a * (45 - SPARK_ADVANCE) / 180;
+      uint32_t t_spark = t_now + d_spark;
       // TODO: schedule spark
     }
   }