Use buffer to protect SCS from software faults when reading from uC

To satisfy rule EV 4.11.5

Resolves #4
Resolves #12

sdcl-hardware/npl.kicad_sch

@@ -903,71 +903,6 @@
         )
       )
     )
-    (symbol "Device:D_Schottky" (pin_numbers hide) (pin_names (offset 1.016) hide) (in_bom yes) (on_board yes)
-      (property "Reference" "D" (id 0) (at 0 2.54 0)
-        (effects (font (size 1.27 1.27)))
-      )
-      (property "Value" "D_Schottky" (id 1) (at 0 -2.54 0)
-        (effects (font (size 1.27 1.27)))
-      )
-      (property "Footprint" "" (id 2) (at 0 0 0)
-        (effects (font (size 1.27 1.27)) hide)
-      )
-      (property "Datasheet" "~" (id 3) (at 0 0 0)
-        (effects (font (size 1.27 1.27)) hide)
-      )
-      (property "ki_keywords" "diode Schottky" (id 4) (at 0 0 0)
-        (effects (font (size 1.27 1.27)) hide)
-      )
-      (property "ki_description" "Schottky diode" (id 5) (at 0 0 0)
-        (effects (font (size 1.27 1.27)) hide)
-      )
-      (property "ki_fp_filters" "TO-???* *_Diode_* *SingleDiode* D_*" (id 6) (at 0 0 0)
-        (effects (font (size 1.27 1.27)) hide)
-      )
-      (symbol "D_Schottky_0_1"
-        (polyline
-          (pts
-            (xy 1.27 0)
-            (xy -1.27 0)
-          )
-          (stroke (width 0) (type default) (color 0 0 0 0))
-          (fill (type none))
-        )
-        (polyline
-          (pts
-            (xy 1.27 1.27)
-            (xy 1.27 -1.27)
-            (xy -1.27 0)
-            (xy 1.27 1.27)
-          )
-          (stroke (width 0.254) (type default) (color 0 0 0 0))
-          (fill (type none))
-        )
-        (polyline
-          (pts
-            (xy -1.905 0.635)
-            (xy -1.905 1.27)
-            (xy -1.27 1.27)
-            (xy -1.27 -1.27)
-            (xy -0.635 -1.27)
-            (xy -0.635 -0.635)
-          )
-          (stroke (width 0.254) (type default) (color 0 0 0 0))
-          (fill (type none))
-        )
-      )
-      (symbol "D_Schottky_1_1"
-        (pin passive line (at -3.81 0 0) (length 2.54)
-          (name "K" (effects (font (size 1.27 1.27))))
-          (number "1" (effects (font (size 1.27 1.27))))
-        )
-        (pin passive line (at 3.81 0 180) (length 2.54)
-          (name "A" (effects (font (size 1.27 1.27))))
-          (number "2" (effects (font (size 1.27 1.27))))
-        )
-      )
-    )
     (symbol "Device:LED" (pin_numbers hide) (pin_names (offset 1.016) hide) (in_bom yes) (on_board yes)
       (property "Reference" "D" (id 0) (at 0 2.54 0)
         (effects (font (size 1.27 1.27)))
@@ -1190,6 +1125,9 @@
   (junction (at 114.3 105.41) (diameter 0) (color 0 0 0 0)
     (uuid 17205334-8d6e-4ec9-afee-5485d66bfdb1)
   )
+  (junction (at 125.73 121.92) (diameter 0) (color 0 0 0 0)
+    (uuid 20616256-d2d6-4aa9-b999-a31d29a24f36)
+  )
   (junction (at 224.79 93.98) (diameter 0) (color 0 0 0 0)
     (uuid 27373484-7b88-483b-87bb-dc98c4baecb2)
   )
@@ -1199,6 +1137,9 @@
   (junction (at 129.54 63.5) (diameter 0) (color 0 0 0 0)
     (uuid 30cba68f-1f49-47e1-afe6-fcad563e9252)
   )
+  (junction (at 220.98 116.84) (diameter 0) (color 0 0 0 0)
+    (uuid 412423e0-14df-4ad6-98a0-a216e4ef65f5)
+  )
   (junction (at 168.91 90.17) (diameter 0) (color 0 0 0 0)
     (uuid 4828c262-84aa-441d-8dad-6ae63025bf61)
   )
@@ -1238,6 +1179,9 @@
   (junction (at 76.2 46.99) (diameter 0) (color 0 0 0 0)
     (uuid d3d4329e-fd16-40b2-9537-230d42c119d0)
   )
+  (junction (at 168.91 98.425) (diameter 0) (color 0 0 0 0)
+    (uuid e53eafba-f419-4375-9d66-034a950d86f6)
+  )
   (junction (at 87.63 40.64) (diameter 0) (color 0 0 0 0)
     (uuid eb432c68-9e96-480c-b1e5-cac6fcf77253)
   )
@@ -1256,6 +1200,10 @@
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid 05090b39-e3ad-4c4b-b667-1484694735e5)
   )
+  (wire (pts (xy 168.91 98.425) (xy 168.91 119.38))
+    (stroke (width 0) (type default) (color 0 0 0 0))
+    (uuid 0f8e12d8-66f0-4d01-9807-8a1bf48fe430)
+  )
   (wire (pts (xy 140.335 127) (xy 144.78 127))
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid 0fbee36c-e54d-4ba5-aca6-4f76858c0774)
@@ -1276,6 +1224,10 @@
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid 19c2ede5-9c92-4af2-afa8-cbd2dca5a3d3)
   )
+  (wire (pts (xy 133.985 135.255) (xy 125.73 135.255))
+    (stroke (width 0) (type default) (color 0 0 0 0))
+    (uuid 19e11f7f-d84d-46e7-a9a1-1cc9ce02617a)
+  )
   (wire (pts (xy 113.03 50.8) (xy 138.43 50.8))
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid 1b76406f-deff-4733-b380-a3e992efb328)
@@ -1300,6 +1252,10 @@
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid 3c4020e3-b3cb-4314-8d0f-95cd0ed22d76)
   )
+  (wire (pts (xy 250.825 67.31) (xy 248.92 67.31))
+    (stroke (width 0) (type default) (color 0 0 0 0))
+    (uuid 48f03ae6-7d4c-4418-9300-a7f9176570d2)
+  )
   (wire (pts (xy 224.79 93.98) (xy 224.79 77.47))
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid 50350130-8969-45f0-84a1-27eef7283e87)
@@ -1312,6 +1268,10 @@
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid 53a11451-75f6-4a8c-b089-ac1759590fc8)
   )
+  (wire (pts (xy 125.73 121.92) (xy 144.78 121.92))
+    (stroke (width 0) (type default) (color 0 0 0 0))
+    (uuid 59ccc5e0-ead4-46cb-a92d-b288a63e97a5)
+  )
   (wire (pts (xy 63.5 46.99) (xy 76.2 46.99))
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid 5e14ed83-cb91-4a52-b75f-195ad28299e2)
@@ -1340,7 +1300,7 @@
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid 798b3f16-4531-441c-89da-319760a102d2)
   )
-  (wire (pts (xy 168.91 90.17) (xy 168.91 119.38))
+  (wire (pts (xy 168.91 90.17) (xy 168.91 98.425))
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid 834893da-9bd7-4ccf-b48f-918695a09d89)
   )
@@ -1380,14 +1340,22 @@
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid 8fdd753c-282e-47fd-84e0-cf25336ec51e)
   )
-  (wire (pts (xy 123.19 121.92) (xy 144.78 121.92))
+  (wire (pts (xy 123.19 121.92) (xy 125.73 121.92))
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid 8ff35611-d820-4a7b-9f74-8173965c57cd)
   )
+  (wire (pts (xy 220.98 116.84) (xy 233.045 116.84))
+    (stroke (width 0) (type default) (color 0 0 0 0))
+    (uuid 90d24c11-8da1-48c2-8fdd-ed65993fe450)
+  )
   (wire (pts (xy 129.54 63.5) (xy 129.54 64.77))
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid 92d43fc1-53cf-4c84-97ae-85cfaeb4353f)
   )
+  (wire (pts (xy 125.73 135.255) (xy 125.73 121.92))
+    (stroke (width 0) (type default) (color 0 0 0 0))
+    (uuid 9b7b419d-ae12-4ffc-a880-b780c656af78)
+  )
   (wire (pts (xy 220.98 111.76) (xy 224.79 111.76))
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid a0d362b0-8870-491f-97aa-c192ca1f0a79)
@@ -1412,10 +1380,6 @@
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid b0a9ee0c-a43c-4980-9af8-05fa92f4c675)
   )
-  (wire (pts (xy 113.03 40.64) (xy 113.03 39.37))
-    (stroke (width 0) (type default) (color 0 0 0 0))
-    (uuid ba57455a-506f-471f-989d-ffc8c3839471)
-  )
   (wire (pts (xy 63.5 52.07) (xy 80.01 52.07))
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid bb804471-b8a1-4a1e-a2aa-ce2cc0c88d66)
@@ -1428,6 +1392,10 @@
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid bce75bc7-1857-406e-af4c-2e3cbcb1af9e)
   )
+  (wire (pts (xy 248.92 67.31) (xy 248.92 74.93))
+    (stroke (width 0) (type default) (color 0 0 0 0))
+    (uuid bd834248-7ebf-464c-88a8-9711f9a204eb)
+  )
   (wire (pts (xy 146.05 85.09) (xy 146.05 87.63))
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid c1ee9d6e-edb3-4215-8476-f4f4f983ade2)
@@ -1436,7 +1404,7 @@
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid cdcf458d-bc94-4ad2-9d3f-2b27d18039d3)
   )
-  (wire (pts (xy 113.03 48.26) (xy 113.03 50.8))
+  (wire (pts (xy 113.03 39.37) (xy 113.03 50.8))
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid ce2745ea-4de5-40af-be0d-1cda790fd766)
   )
@@ -1456,6 +1424,10 @@
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid ea2888dc-1327-4dbc-95ac-5387b69ddb0e)
   )
+  (wire (pts (xy 168.91 98.425) (xy 170.815 98.425))
+    (stroke (width 0) (type default) (color 0 0 0 0))
+    (uuid ebb68e3b-94ef-4c66-b9d9-8c16f69a8ed3)
+  )
   (wire (pts (xy 245.11 74.93) (xy 248.92 74.93))
     (stroke (width 0) (type default) (color 0 0 0 0))
     (uuid eea94b83-b2c4-46ba-8e8e-160b87d3711a)
@@ -1489,10 +1461,6 @@
     (effects (font (size 1.27 1.27)) (justify right bottom))
     (uuid 6fcc41f5-86b4-4f8d-ba55-add28542e773)
   )
-  (text "Diode to satisfy EV 4.11.4" (at 110.49 36.83 0)
-    (effects (font (size 1.27 1.27)) (justify left bottom))
-    (uuid 802128a1-9fdf-483d-94de-a9edea35dd2a)
-  )
 
   (label "~{reopen}" (at 196.85 121.92 0)
     (effects (font (size 1.27 1.27)) (justify left bottom))
@@ -1534,7 +1502,7 @@
     (effects (font (size 1.27 1.27)) (justify left bottom))
     (uuid c0be3071-206a-4603-94a7-5f4204d90b0c)
   )
-  (label "closed" (at 247.65 74.93 0)
+  (label "closed" (at 248.92 74.93 0)
     (effects (font (size 1.27 1.27)) (justify left bottom))
     (uuid d7acfe44-757c-413d-9db3-ea2b40789eee)
   )
@@ -1547,6 +1515,35 @@
     (uuid fd862b97-bc59-43ae-97c9-bf49c97ff6b4)
   )
 
+  (global_label "WD_OK" (shape output) (at 133.985 135.255 0) (fields_autoplaced)
+    (effects (font (size 1.27 1.27)) (justify left))
+    (uuid 077b02f1-82d7-4802-996a-c7579c511d19)
+    (property "Intersheet References" "${INTERSHEET_REFS}" (id 0) (at 142.5987 135.1756 0)
+      (effects (font (size 1.27 1.27)) (justify left) hide)
+    )
+  )
+  (global_label "CLOSED" (shape output) (at 250.825 67.31 0) (fields_autoplaced)
+    (effects (font (size 1.27 1.27)) (justify left))
+    (uuid 5d453815-6eff-4db2-b235-d886052dd4d3)
+    (property "Intersheet References" "${INTERSHEET_REFS}" (id 0) (at 260.4063 67.2306 0)
+      (effects (font (size 1.27 1.27)) (justify left) hide)
+    )
+  )
+  (global_label "INITIAL_OPEN" (shape output) (at 170.815 98.425 0) (fields_autoplaced)
+    (effects (font (size 1.27 1.27)) (justify left))
+    (uuid 89a1a742-37a0-470f-bfe0-1c3376976868)
+    (property "Intersheet References" "${INTERSHEET_REFS}" (id 0) (at 185.4159 98.3456 0)
+      (effects (font (size 1.27 1.27)) (justify left) hide)
+    )
+  )
+  (global_label "REOPENED" (shape output) (at 233.045 116.84 0) (fields_autoplaced)
+    (effects (font (size 1.27 1.27)) (justify left))
+    (uuid c0141437-606f-44f1-bbd0-f6d707c26aed)
+    (property "Intersheet References" "${INTERSHEET_REFS}" (id 0) (at 245.2873 116.7606 0)
+      (effects (font (size 1.27 1.27)) (justify left) hide)
+    )
+  )
+
   (hierarchical_label "SDC_in_3V3" (shape input) (at 140.335 127 180)
     (effects (font (size 1.27 1.27)) (justify right))
     (uuid 1e5effb6-4427-4d83-9020-853fc3da73e7)
@@ -2106,25 +2103,6 @@
     (pin "1" (uuid c21eb1fa-0372-4017-8f6c-7827580739f0))
   )
 
-  (symbol (lib_id "Device:D_Schottky") (at 113.03 44.45 90) (mirror x) (unit 1)
-    (in_bom yes) (on_board yes)
-    (uuid 00000000-0000-0000-0000-000061b65c4f)
-    (property "Reference" "D4" (id 0) (at 115.062 45.6184 90)
-      (effects (font (size 1.27 1.27)) (justify right))
-    )
-    (property "Value" "BAT54HMFH" (id 1) (at 115.062 43.307 90)
-      (effects (font (size 1.27 1.27)) (justify right))
-    )
-    (property "Footprint" "Diode_SMD:D_SOT-23_ANK" (id 2) (at 113.03 44.45 0)
-      (effects (font (size 1.27 1.27)) hide)
-    )
-    (property "Datasheet" "~" (id 3) (at 113.03 44.45 0)
-      (effects (font (size 1.27 1.27)) hide)
-    )
-    (pin "1" (uuid 6b1220fa-2d6c-4ee2-8346-2501515fe8da))
-    (pin "2" (uuid a49892d8-ca7b-4941-91dc-126e230fd897))
-  )
-
   (symbol (lib_id "power:GND") (at 69.85 120.65 0) (unit 1)
     (in_bom yes) (on_board yes)
     (uuid 00000000-0000-0000-0000-000061b66f8c)
@@ -2490,19 +2468,19 @@
     (pin "1" (uuid 32fdb824-89c9-4364-af28-f8c01f9521cd))
   )
 
-  (symbol (lib_id "Device:LED") (at 176.53 93.98 90) (unit 1)
+  (symbol (lib_id "Device:LED") (at 180.34 90.17 180) (unit 1)
     (in_bom yes) (on_board yes)
     (uuid 00000000-0000-0000-0000-000061bbdc01)
-    (property "Reference" "D9" (id 0) (at 179.5272 92.9894 90)
+    (property "Reference" "D9" (id 0) (at 179.3494 87.1728 90)
       (effects (font (size 1.27 1.27)) (justify right))
     )
-    (property "Value" "Green LED" (id 1) (at 179.5272 95.3008 90)
+    (property "Value" "Green LED" (id 1) (at 181.6608 87.1728 90)
       (effects (font (size 1.27 1.27)) (justify right))
     )
-    (property "Footprint" "Diode_SMD:D_0603_1608Metric_Pad1.05x0.95mm_HandSolder" (id 2) (at 176.53 93.98 0)
+    (property "Footprint" "Diode_SMD:D_0603_1608Metric_Pad1.05x0.95mm_HandSolder" (id 2) (at 180.34 90.17 0)
       (effects (font (size 1.27 1.27)) hide)
     )
-    (property "Datasheet" "~" (id 3) (at 176.53 93.98 0)
+    (property "Datasheet" "~" (id 3) (at 180.34 90.17 0)
       (effects (font (size 1.27 1.27)) hide)
     )
     (pin "1" (uuid ceabe1bb-8df8-49a1-90f1-73b9472dab04))
@@ -2524,17 +2502,17 @@
     (pin "2" (uuid b290b50a-0351-4f05-84f0-c2ddb0a1eacb))
   )
 
-  (symbol (lib_id "power:GND") (at 176.53 97.79 0) (unit 1)
+  (symbol (lib_id "power:GND") (at 184.15 90.17 0) (unit 1)
     (in_bom yes) (on_board yes)
     (uuid 00000000-0000-0000-0000-000061bbdc0d)
-    (property "Reference" "#PWR0158" (id 0) (at 176.53 104.14 0)
+    (property "Reference" "#PWR0158" (id 0) (at 184.15 96.52 0)
       (effects (font (size 1.27 1.27)) hide)
     )
-    (property "Value" "GND" (id 1) (at 176.657 102.1842 0))
-    (property "Footprint" "" (id 2) (at 176.53 97.79 0)
+    (property "Value" "GND" (id 1) (at 184.277 94.5642 0))
+    (property "Footprint" "" (id 2) (at 184.15 90.17 0)
       (effects (font (size 1.27 1.27)) hide)
     )
-    (property "Datasheet" "" (id 3) (at 176.53 97.79 0)
+    (property "Datasheet" "" (id 3) (at 184.15 90.17 0)
       (effects (font (size 1.27 1.27)) hide)
     )
     (pin "1" (uuid f1d1d377-4311-4d50-9258-b734b717fa0b))