From dcba2c00fef8b38bd63df1f99edba9915e127b68 Mon Sep 17 00:00:00 2001
From: josh <josh@bd8a9e45-a331-0410-811e-c64571078777>
Date: Sun, 3 May 2009 20:50:34 +0000
Subject: [PATCH] added setPPLines(), sendNibble(), and sendByte() VFD
 functions

git-svn-id: svn://anubis/misc/parport-2x20vfd@111 bd8a9e45-a331-0410-811e-c64571078777
---
 VFD.cc | 28 ++++++++++++++++++++++++++++
 VFD.h  | 17 +++++++++++++----
 2 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/VFD.cc b/VFD.cc
index 1ea06a4..0d0ab29 100644
--- a/VFD.cc
+++ b/VFD.cc
@@ -69,3 +69,31 @@ void VFD::disconnect()
         m_ppfd = -1;
     }
 }
+
+void VFD::setPPLines(unsigned char bits)
+{
+    if (m_ppfd >= 0)
+    {
+        ioctl(m_ppfd, PPWDATA, &bits);
+    }
+}
+
+void VFD::sendNibble(unsigned char rs, unsigned char dat)
+{
+    setPPLines(  (rs << PP_OFFSET_RS)
+               | (E_DISABLE << PP_OFFSET_E)
+               | (RW_WRITE << PP_OFFSET_RW)
+               | ((dat & 0xF) << PP_OFFSET_DATA) );
+    usleep(1);
+    setPPLines(  (rs << PP_OFFSET_RS)
+               | (E_ENABLE << PP_OFFSET_E)
+               | (RW_WRITE << PP_OFFSET_RW)
+               | ((dat & 0xF) << PP_OFFSET_DATA) );
+    usleep(1);
+}
+
+void VFD::sendByte(unsigned char rs, unsigned char dat)
+{
+    sendNibble(rs, (dat >> 4) & 0xF);
+    sendNibble(rs, dat & 0xF);
+}
diff --git a/VFD.h b/VFD.h
index 6cde201..8d15bf4 100644
--- a/VFD.h
+++ b/VFD.h
@@ -32,17 +32,26 @@
 class VFD
 {
     public:
+        VFD();
+        bool connect(const std::string & parport = "/dev/parport0");
+        void disconnect();
+
+    protected:
         static const unsigned char RW_WRITE = 0;
         static const unsigned char RW_READ = 1;
         static const unsigned char E_ENABLE = 0;
         static const unsigned char E_DISABLE = 1;
         static const unsigned char RS_COMMAND = 0;
         static const unsigned char RS_DATA = 1;
-        VFD();
-        bool connect(const std::string & parport = "/dev/parport0");
-        void disconnect();
+        static const unsigned char PP_OFFSET_RS = 0;
+        static const unsigned char PP_OFFSET_RW = 1;
+        static const unsigned char PP_OFFSET_E = 2;
+        static const unsigned char PP_OFFSET_DATA = 3;
+
+        void sendByte(unsigned char rs, unsigned char dat);
+        void sendNibble(unsigned char rs, unsigned char dat);
+        void setPPLines(unsigned char bits);
 
-    protected:
         int m_ppfd;     /* parallel port file descriptor */
 };