add bugs.txt to kicad folder, in order to keep track of PCB design bugs

kicad/bugs.txt

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+Known bugs
+
+Revision Current (no date yet)
+------------------------------
+
+
+Revision 2022-06-07
+-------------------
+- The PCF8574 is not suitable for our needs, as it can't source enough current
+  (300 µA max). Also it has a too-high leakage current, so that the relays are
+  switched on permanently, when the pins are in input state.
+  Workaround: Replace the part with the pin compatible PCA9554D
+  Will be fixed upon redesign/cleanup.
+
+- The DMP3098 transistor is integrated backwards (swapped Source/Drain)
+  Workaround: Remove Q2 and the resistors, replace Q1 with a
+  suitable N-channel part like AO3422
+  Will be fixed upon redesign/cleanup.
+
+- The pulldown resistor for the TCS signal bus has a too small footprint for the
+  current it has to withstand, and the needed value isn't determined properly yet.
+  Workaround: Solder a 1x2 female header on the pcb pads of Q1 (or the nearby
+  desoldered resistor) and the tcs signal, for providing a swappable method (wired
+  resistor).
+  Will be fixed upon redesign/cleanup, utilising a 1x2 2.54mm tht footprint and a
+  1206 resistor footprint in parallel
+
+- ESP32 (azdelivery) has a wrong symbol where the "CMD" pin is labelled as GND, which
+  resulted in a short to GND on this pin.
+  Workaround: Remove the contacts from the pinheader that connects the PCB to the ESP.
+  Will be fixed upon redesign/cleanup.
+
+- ESP32 GPIO12 is not supposed to be pulled up HIGH during boot (the pin doubles as a
+  bootstrapping pin, and will result in a boot loop if set to HIGH)
+  Workaround: Cut trace at the GPIO12 pin, connect the signal to GPIO13
+  Will be fixed upon redesign/cleanup.