From 2e87e5454bb48d71068fe44d2021e58788a315b8 Mon Sep 17 00:00:00 2001
From: Tom Nisbet <t.talk@nisbethome.com>
Date: Sat, 14 Nov 2020 14:53:55 -0500
Subject: [PATCH] Note the connection of the 74LS595 G/OE pin

---
 docs/hardware.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/docs/hardware.md b/docs/hardware.md
index 9b5088d..90326bf 100644
--- a/docs/hardware.md
+++ b/docs/hardware.md
@@ -51,6 +51,10 @@ larger chips like the 27C040.
 3. The D13 pin controls the output register on the '595 shift registers.  The code for
 this must be enabled in Configure.h.  This pin is not connected when using the 74LS164.
 
+Also note that the 74LS595 has an output enable pin, labeled as either G or OE
+in the datasheet.  This pin must be connected to ground for both chips or else
+they will not produce any signal on their output lines.
+
 The two shift registers can produce a sixteen bit address, although the 28C256 only needs
 15 addresses. Chips larger than 64K are supported by using the shift registers for A<sub>0</sub>..A<sub>15</sub>
 and connecting Arduino pins D10..D12 to the chip's A<sub>16</sub>..A<sub>18</sub>