From 04b297de20f370aa21ddcc7c82090e554fdd2250 Mon Sep 17 00:00:00 2001
From: Tony Corbett G0WFV <tonyc.uk@gmail.com>
Date: Mon, 27 Jun 2016 18:48:13 +0100
Subject: [PATCH] Support for HD44780 via PCF8574

---
 HD44780.cpp         | 36 +++++++++++++++++++++++++++++++++++-
 HD44780.h           | 33 ++++++++++++++++++++++++++-------
 Makefile.Pi.PCF8574 | 24 ++++++++++++++++++++++++
 3 files changed, 85 insertions(+), 8 deletions(-)
 create mode 100644 Makefile.Pi.PCF8574

diff --git a/HD44780.cpp b/HD44780.cpp
index d9ecad1..41abac3 100644
--- a/HD44780.cpp
+++ b/HD44780.cpp
@@ -206,12 +206,16 @@ bool CHD44780::open()
   adafruitLCDSetup();
 #endif
 
+#ifdef PCF8574_DISPLAY
+	pcf8574LCDSetup();
+#endif
+
 	m_fd = ::lcdInit(m_rows, m_cols, 4, m_rb, m_strb, m_d0, m_d1, m_d2, m_d3, 0, 0, 0, 0);
 	if (m_fd == -1) {
 		LogError("Unable to open the HD44780");
 		return false;
 	}
-
+	
 	::lcdDisplay(m_fd, 1);
 	::lcdCursor(m_fd, 0);
 	::lcdCursorBlink(m_fd, 0);
@@ -296,6 +300,36 @@ void CHD44780::adafruitLCDColour(ADAFRUIT_COLOUR colour)
 }
 #endif
 
+#ifdef PCF8574_DISPLAY
+void CHD44780::pcf8574LCDSetup()
+{
+	// Initalize PFC8574
+	::pcf8574Setup(AF_BASE, PCF8574);
+
+	// Initialise LCD
+	m_fd = ::lcdInit(m_rows, m_cols, 4, AF_RS, AF_E, AF_D1, AF_D2, AF_D3, AF_D4, 0, 0, 0, 0);
+	if (m_fd == -1) {
+		LogError("Unable to open the HD44780 via I2C");
+		return false;
+	}
+
+	m_rb   = AF_RS;
+	m_strb = AF_E;
+	m_d0   = AF_D1;
+	m_d1   = AF_D2;
+	m_d2   = AF_D3;
+	m_d3   = AF_D4;
+
+	// Turn on backlight
+	::pinMode (AF_BL, OUTPUT);
+	::digitalWrite (AF_BL, 1);
+
+	// Set LCD to write mode.
+	::pinMode (AF_RW, OUTPUT);
+	::digitalWrite (AF_RW, 0);
+}
+#endif
+
 void CHD44780::setIdleInt()
 {
 	m_dmrScrollTimer1.stop();                // Stop the scroll timer on slot 1
diff --git a/HD44780.h b/HD44780.h
index 7cd3805..d9cf276 100644
--- a/HD44780.h
+++ b/HD44780.h
@@ -26,6 +26,7 @@
 #include <vector>
 
 #include <mcp23017.h>
+#include <pcf8574.h>
 
 enum ADAFRUIT_COLOUR {
 	AC_OFF,
@@ -40,14 +41,28 @@ enum ADAFRUIT_COLOUR {
 
 // Defines for the Adafruit Pi LCD interface board
 #ifdef ADAFRUIT_DISPLAY
-#define AF_BASE         100
-#define AF_RED          (AF_BASE + 6)
-#define AF_GREEN        (AF_BASE + 7)
-#define AF_BLUE         (AF_BASE + 8)
-#define AF_RW           (AF_BASE + 14)
-#define AF_ON		LOW
+#define AF_BASE   100
+#define AF_RED    (AF_BASE + 6)
+#define AF_GREEN  (AF_BASE + 7)
+#define AF_BLUE   (AF_BASE + 8)
+#define AF_RW     (AF_BASE + 14)
+#define AF_ON		  LOW
 #define AF_OFF		HIGH
-#define MCP23017        0x20
+#define MCP23017  0x20
+#endif
+
+// Define for HD44780 connected via a PCF8574 GPIO extender
+#ifdef PCF8574_DISPLAY
+#define AF_BASE   100
+#define AF_RS     (AF_BASE + 0)
+#define AF_RW     (AF_BASE + 1)
+#define AF_E      (AF_BASE + 2)
+#define AF_BL     (AF_BASE + 3)
+#define AF_D1     (AF_BASE + 4)
+#define AF_D2     (AF_BASE + 5)
+#define AF_D3     (AF_BASE + 6)
+#define AF_D4     (AF_BASE + 7)
+#define PCF8547		0x27
 #endif
 
 class CHD44780 : public CDisplay
@@ -105,6 +120,10 @@ private:
   void adafruitLCDSetup();
   void adafruitLCDColour(ADAFRUIT_COLOUR colour);
 #endif
+
+#ifdef PCF8574_DISPLAY
+  void pcf8574LCDSetup();
+#endif
 };
 
 #endif
diff --git a/Makefile.Pi.PCF8574 b/Makefile.Pi.PCF8574
new file mode 100644
index 0000000..e597fa4
--- /dev/null
+++ b/Makefile.Pi.PCF8574
@@ -0,0 +1,24 @@
++# This makefile is for use with the Raspberry Pi when using an HD44780 compatible display. The wiringpi library is needed.
++# Support for the HD44780 connected via a PCF8574 8-bit GPIO expander IC
++CC      = gcc
++CXX     = g++
++CFLAGS  = -g -O3 -Wall -std=c++0x -pthread -DHD44780 -DPCF8574_DISPLAY -I/usr/local/include
++LIBS    = -lwiringPi -lwiringPiDev -lpthread
++LDFLAGS = -g -L/usr/local/lib
++
++OBJECTS = \
++		AMBEFEC.o BPTC19696.o Conf.o CRC.o Display.o DMRControl.o DMRCSBK.o DMRData.o DMRDataHeader.o DMREMB.o DMREmbeddedLC.o DMRFullLC.o DMRIPSC.o DMRLookup.o DMRLC.o \
++		DMRShortLC.o DMRSlot.o DMRSlotType.o DStarControl.o DStarHeader.o DStarNetwork.o DStarSlowData.o Golay2087.o Golay24128.o Hamming.o HD44780.o Log.o MMDVMHost.o \
++		Modem.o Nextion.o NullDisplay.o QR1676.o RS129.o SerialController.o SHA256.o StopWatch.o Sync.o TFTSerial.o Thread.o Timer.o UDPSocket.o Utils.o YSFControl.o \
++		YSFConvolution.o YSFFICH.o YSFNetwork.o YSFPayload.o
++
++all:		MMDVMHost
++
++MMDVMHost:	$(OBJECTS)
++		$(CXX) $(OBJECTS) $(CFLAGS) $(LIBS) -o MMDVMHost
++
++%.o: %.cpp
++		$(CXX) $(CFLAGS) -c -o $@ $<
++
++clean:
++		$(RM) MMDVMHost *.o *.d *.bak *~