# HG changeset patch
# User Mychaela Falconia <falcon@freecalypso.org>
# Date 1602571343 0
# Node ID db344818b323e605026ca1567bbc77a961d02021
# Parent  14b8e532c9666bdaa182d7337575f0d3b6f5a667
DUART28-with-FCDEV3B article written

diff -r 14b8e532c966 -r db344818b323 DUART28-with-FCDEV3B
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DUART28-with-FCDEV3B	Tue Oct 13 06:42:23 2020 +0000
@@ -0,0 +1,46 @@
+This article describes how to connect FreeCalypso DUART28 adapter to an FCDEV3B
+target board, both the main connection of dual UART and optional boot control
+connections.
+
+Main connection: dual UART
+==========================
+
+The main connection of two UARTs is made with a 10-wire ribbon cable.  You
+should have received the correct cable from Falconia Partners LLC together with
+your FCDEV3B+DUART28 board kit - it is a rainbow-colored 10-wire ribbon cable
+with two different end terminations: one end is terminated with a blue IDC
+connector, the other end is terminated with a black connector into which
+individual wires are inserted from the top.  The blue connector goes to the
+DUART28, the black connector goes to the FCDEV3B.
+
+The blue connector going to the DUART28 board is keyed such that it can be
+inserted in only one orientation, hence that one is expected to be always
+correct.  The black connector goes to the middle of the three headers on
+FCDEV3B (J301), and in this case you are responsible for ensuring the correct
+orientation.  If you are using the official DUART28 to FCDEV3B cable from
+Falconia Partners LLC, then the side with brown and red wires needs to be
+facing toward JTAG and power input connectors.
+
+Optional boot control provision
+===============================
+
+If you wish to connect the optional boot control signals, connect two
+individual jumper wires as follows:
+
+* For PWON control, connect DUART28 CTL1 to the top pin of 2-pin header JP1 on
+  FCDEV3B, namely the pin that is closer to the adjacent PWON button.  (The
+  other pin on JP1 is ground.)
+
+* For RESET control, connect DUART28 CTL2 to JTAG connector J310 pin 2 on
+  FCDEV3B, which is the XDS_RESET signal.  Naturally one cannot connect both
+  DUART28 CTL2 and JTAG at the same time.
+
+* Ground connection between the two boards will normally be provided by the
+  main dual UART cable.
+
+If you are going to connect these boot control signals, you MUST reprogram the
+EEPROM on your DUART28 board to the DUART28C configuration and apply the
+necessary DUART28C support patch to your Linux kernel ftdi_sio driver -
+otherwise your hardware setup will be inoperable, with FCDEV3B getting held
+down in reset whenever the second serial port is opened for regular serial
+communication.