Version 4
SHEET 1 916 680
WIRE 16 48 -32 48
WIRE 128 48 96 48
WIRE 144 48 128 48
WIRE -32 64 -32 48
WIRE 144 64 144 48
WIRE -32 160 -32 144
WIRE -32 160 -64 160
WIRE 144 160 144 128
WIRE 144 160 -32 160
WIRE -64 176 -64 160
FLAG -64 176 0
FLAG -32 48 DC3v3
FLAG 128 48 vpin
SYMBOL voltage -32 48 R0
WINDOW 3 -66 80 Left 2
WINDOW 39 0 0 Left 2
WINDOW 0 -64 17 Left 2
SYMATTR Value 3.3
SYMATTR Value2 AC 0 0
SYMATTR InstName V1
SYMBOL res 112 32 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 10k
SYMBOL cap 128 64 R0
SYMATTR InstName C1
SYMATTR Value 125p
TEXT -8 176 Left 2 !.tran 4u
TEXT 136 176 Left 2 !.ic V(vpin)=0
TEXT -104 224 Left 2 ;From http://forums.parallax.com/discussion/comment/1463938/#Comment_1463938\nTarget 1us and 1.80V appx as rise time to match, by varying C1\nGuess 33pF ->  263.8106n  33*1u/263.8106n = 125pF\nModify 125pF -> 999ns & 1.81V