document v1 in changelog

CHANGELOG.md

@@ -1,3 +1,24 @@
+v1
+--
+
+second prototype built.
+
+needs a couple of small fixes, but works much better.
+
+fixes (from v0):
+- an LDO replaces the zener diode as voltage reference
+- the voltage reference (2.1V) is below common-mode input-voltage range
+- USB-C plug tab mounting holes made larger
+
+additions:
+- quad op-amp instead of dual op-amp is used
+- other 2 op-amp circuits are used to indicate over-voltage using an LED
+- more compact dual common-cathode diodes are used
+
+errors:
+- no decoupling caps around LDO
+- no clearance around USB-C receptacle mount holes, causing the non-plated hole to be fabbed plated, and shorting ground to internal layers
+
 v0
 --