complete the switch to SS49E hall sensor

ss49e.c

@@ -0,0 +1,38 @@
+#include "ss49e.h"
+
+void ss49e_init(SS49E_State *self, enum MagnetPolarityType magnetPolarityType, ss49e_tick_callback_t tickCallback) {
+  self->workingPhase = SS49E_WORKING_PHASE_NORMAL;
+  self->tickCallback = tickCallback;
+
+  self->magnetPolType = magnetPolarityType;
+  const float level0 = 2445.0f / 4095.0f;
+  const float deviation = 380.0f / 4095.0f;
+  if (magnetPolarityType == MAGNET_POLTYPE_BIPOLAR) {
+    // self->threshold01 = level0 + deviation * 0.75;
+    // self->threshold10 = level0 - deviation * 0.75;
+    self->threshold01 = (2447.0 + 520.0 * 2.0 / 3.0) / 4095.0;
+    self->threshold10 = (2447.0 - 800.0 * 2.0 / 3.0) / 4095.0;
+  } else {
+    float activeLevel = level0 + (magnetPolarityType == MAGNET_POLTYPE_UNIPOLAR_POSITIVE ? deviation : -deviation);
+    self->threshold01 = level0 * 1 / 3 + activeLevel * 2 / 3;
+    self->threshold10 = activeLevel * 1 / 3 + level0 * 2 / 3;
+  }
+  self->currentLevel = 0;
+}
+
+void ss49e_process_sample(SS49E_State *self, uint16_t sample) {
+  float normalized = (float)sample / 4095.0f;
+  if (self->currentLevel == 0) {
+    if (normalized >= self->threshold01) {
+      self->currentLevel = 1;
+      if (self->magnetPolType == MAGNET_POLTYPE_BIPOLAR || self->magnetPolType == MAGNET_POLTYPE_UNIPOLAR_POSITIVE)
+        self->tickCallback();
+    }
+  } else {
+    if (normalized <= self->threshold10) {
+      self->currentLevel = 0;
+      if (self->magnetPolType == MAGNET_POLTYPE_BIPOLAR || self->magnetPolType == MAGNET_POLTYPE_UNIPOLAR_NEGATIVE)
+        self->tickCallback();
+    }
+  }
+}