Diff: MBED_ControlBus.cpp

Revision:

0:2467aed99127

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MBED_ControlBus.cpp	Wed Aug 31 19:45:31 2011 +0000
@@ -0,0 +1,136 @@
+/* MBED_ControlBus - Use MBED Port Pins for controlling the external Bus
+ * Copyright (c) 2011 Wim Huiskamp
+ *
+ * Released under the MIT License: http://mbed.org/license/mit
+ *
+ * version 0.2 Initial Release
+*/
+#include "mbed.h"
+#include "MBED_ControlBus.h"
+
+
+/** Create an MBED_ControlBus object connected to the specified Pins
+ *
+ * @param PinName WR the Write pin 
+ * @param PinName RD the Read pin 
+ * @param PinName DTR the databuffer Transmit/Receive direction pin 
+ * @param PinName CDBUF the databuffer enable pin
+ * @param PinName CDINT the Keyboard interrupt pin  
+*/
+MBED_ControlBus::MBED_ControlBus(PinName WR, PinName RD, PinName DTR, PinName CDBUF, PinName CDINT) :
+   _WR(WR),        // WR pin
+   _RD(RD),        // RD pin
+   _DTR(DTR),      // DTR pin
+   _CDBUF(CDBUF),  // CDBUF pin   
+   _CDINT(CDINT){  // CDINT pin      
+   _init();
+}
+
+
+/** Set or Clear the WR pin on Control Bus
+ *
+ * @param Bit_Level wr_level
+*/
+void MBED_ControlBus::WR (Bit_Level wr_level) {
+
+    if (wr_level == LOW) {
+        // Make sure that databus buffer is enabled for Write
+        //busctrl(ENABLE, WRITE);        
+             
+        _RD = 1;                    // RD Pin High, make sure there is no collision    
+        _WR = 0;                    // WR Pin Low
+      }               
+    else {
+        _WR = 1;                    // WR Pin High
+    }      
+}
+ 
+
+/** Set or Clear the RD pin on Control Bus
+ *
+ * @param Bit_Level rd_level
+*/
+void MBED_ControlBus::RD (Bit_Level rd_level) {
+
+    if (rd_level == LOW) {
+        // Make sure that databus buffer is enabled for Read
+        //busctrl(ENABLE, READ);
+
+        _WR = 1;                    // WR Pin High, make sure there is no collision    
+        _RD = 0;                    // RD Pin Low
+      }               
+    else {
+        _RD = 1;                    // RD Pin High
+    }      
+}
+               
+
+/** Enable databus buffer for Write or Read
+ *
+ * @param Bus_Dir buf_dir
+*/
+void MBED_ControlBus::busdir (Bus_Dir buf_dir) {
+
+    if (buf_dir == READ) {
+        // Make sure that databus buffer is enabled for READ
+        _DTR   = 0;                 // DTR Pin Low, Read Direction            
+        _CDBUF = 0;                 // CDBUF Pin Low, Enable Buffer                
+      }                
+    else {
+        // Make sure that databus buffer is enabled for Write   
+        _DTR   = 1;                 // DTR Pin High, Write Direction            
+        _CDBUF = 0;                 // CDBUF Pin Low, Enable Buffer
+    }      
+}
+
+
+/** Enable/Disable databus buffer and control Write or Read Direction
+ *
+ * @param Bus_Ena buf_ena
+ * @param Bus_Dir buf_dir
+*/
+void MBED_ControlBus::busctrl (Bus_Ena buf_ena, Bus_Dir buf_dir) {
+
+    if (buf_ena == ENABLE) {
+        _CDBUF = 0;                 // CDBUF Pin Low, Enable Buffer
+      }                
+    else {
+        _CDBUF = 1;                 // CDBUF Pin High, Disable Buffer                
+    }      
+
+    if (buf_dir == READ) {
+        _DTR   = 0;                 // DTR Pin Low, Read Direction            
+      }                
+    else {
+        _DTR   = 1;                 // DTR Pin High, Write Direction            
+    }      
+}
+
+
+/** Get the CDINT pin value from Control Bus
+ *
+ * @returns Bit_Level CDINT_level
+*/
+Bit_Level MBED_ControlBus::CDINT () {
+    
+    // CDINT Pin value, used as regular Pin rather than as interrupt
+    if (_CDINT == 0)
+      return LOW;
+    else 
+      return HIGH;      
+}
+
+
+/** Init MBED_ControlBus
+ * @param
+ * @returns 
+ */
+void MBED_ControlBus::_init() {
+    // Make sure that all Control pins are disabled
+    _RD    = 1;                        // RD Pin High    
+    _WR    = 1;                        // WR Pin High        
+    
+    // Make sure that databus buffer is enabled for Write
+    busctrl(ENABLE, WRITE);
+    
+}
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