Diff: I2CEEPROM.cpp

Revision:

0:5fa232ee5fdf

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/I2CEEPROM.cpp	Tue Jun 04 20:16:33 2013 +0000
@@ -0,0 +1,191 @@
+/*
+ * SOURCE FILE : I2CEEPROM.cpp
+ *
+ * Definition of class I2CEEPROM.
+ * Rountines for communicating with a serial EEPROM over an I2C link.
+ * EEPROM in question is a Microchip 24AA512.
+ * Remember you need pullup resistors on the SCL, SDA and WP lines.
+ *
+ */
+
+#include "I2CEEPROM.h"
+
+/***************/
+/* CONSTRUCTOR */
+/***************/
+I2CEEPROM::I2CEEPROM() :
+    isOpen( false ),
+    // wire( (TwoWire*)NULL ),
+    wp( 8 )
+{
+}
+
+/**************/
+/* DESTRUCTOR */
+/**************/
+I2CEEPROM::~I2CEEPROM() {
+}
+
+/**************************************/
+/* PREPARE TO COMMUNICATE WITH EEPROM */
+/**************************************/
+// Pass pointer to TwoWire object to use for I2C communications
+// which should have been initialised and opened before calling this.
+// Pass 3 bit address of EEPROM (as set by A0, A1 and A2 pins) in ea.
+// Pass pin number to use for write protect in wp.
+#if 0
+void I2CEEPROM::Open( TwoWire *wire, UInt8 ea, UInt8 wp ) {
+    if( ! isOpen ) {
+        // Save pointer to TwoWire object.
+        this->wire = wire;
+        // Calculate slave address.
+        slaveAddress = (UInt8)( ( ea & 0x7 ) | 0x50 );
+        // Save write protect pin number.
+        this->wp = wp;
+        // Configure write protect pin as open drain output.
+        pinMode( wp, OUTPUT_OPEN_DRAIN );
+        // Write protect EEPROM.
+        digitalWrite( wp, HIGH );
+        isOpen = true;
+    }
+}
+#endif
+
+/*********************************************/
+/* SHUT DOWN COMMUNICATIONS LINK WITH EEPROM */
+/*********************************************/
+void I2CEEPROM::Close( void ) {
+    isOpen = false;
+}
+
+// Size of each chunk read or written.
+#define CHUNK_SIZE ( WIRE_BUFSIZ - 2 )
+
+/************************************/
+/* ATTEMPT TO READ A CHUNK OF BYTES */
+/************************************/
+// Pass address within EEPROM in address.
+// Pass pointer to buffer for bytes read in buffer.
+// Returns false if a failure occurred whilst reading EEPROM.
+// Pass number of bytes to read in count.
+// Returns true if successful, false if not.
+// The number of bytes read must not exceed CHUNK_SIZE.
+bool I2CEEPROM::ReadChunk( UInt16 address, UInt8 *buffer, UInt8 count ) {
+#if 0
+  // First send address you want to read from.
+  wire->beginTransmission( slaveAddress );
+  // Add high byte of EEPROM address to read from.
+  wire->send( ( address >> 8 ) & 0xFF );
+  // Add low byte of EEPROM address to read from.
+  wire->send( address & 0xFF );
+  // Send the packet and return false on failure.
+  if( wire->endTransmission() != SUCCESS ) {
+        return false;
+    }
+  // Now read back data.
+  wire->requestFrom( slaveAddress, count );
+    UInt16 readCount = 0;
+  while( ( wire->available() > 0 ) && ( readCount < count ) ) {
+        *buffer++ = wire->receive();
+        readCount++;
+  }
+    return true;
+#else
+  return false;
+#endif
+}
+
+/*************************************/
+/* ATTEMPT TO READ A NUMBER OF BYTES */
+/*************************************/
+// Pass address within EEPROM in address.
+// Pass pointer to buffer for bytes read in buffer.
+// Returns false if a failure occurred whilst reading EEPROM.
+// Pass number of bytes to read in count.
+// Returns true if successful, false if not.
+bool I2CEEPROM::ReadBytes( UInt16 address, UInt8 *buffer, UInt16 count ) {
+#if 0
+    bool ok = true;
+    // Keep reading chunks until all bytes read.
+    while( ( count > 0 ) && ok ) {
+        if( count > CHUNK_SIZE ) {
+            ok = ReadChunk( address, buffer, (UInt8)CHUNK_SIZE );
+            address += CHUNK_SIZE;
+            buffer += CHUNK_SIZE;
+            count -= CHUNK_SIZE;
+        }
+        else {
+            ok = ReadChunk( address, buffer, (UInt8)count );
+            count = 0;
+        }
+    }
+    // Return true on success.
+    return ok;
+#else
+  return false;
+#endif
+}
+
+/**************************************/
+/* ATTEMPT TO WRITE A CHUNK TO EEPROM */
+/**************************************/
+// Pass address within EEPROM in address.
+// Pass pointer to buffer of bytes to write in buffer.
+// Pass number of bytes to write in count.
+// Returns true if successful, false if not.
+// The number of bytes written must not exceed CHUNK_SIZE.
+bool I2CEEPROM::WriteChunk( UInt16 address, const UInt8 *buffer, UInt8 count ) {
+#if 0
+  // First send address you want to write to.
+  wire->beginTransmission( slaveAddress );
+  // Add high byte of EEPROM address to write to.
+  wire->send( ( address >> 8 ) & 0xFF );
+  // Add low byte of EEPROM address to write to.
+  wire->send( address & 0xFF );
+    // Add buffer bytes.
+    wire->send( (uint8*)buffer, count );
+  // Send the packet.
+    // Return true if successful.
+  return ( wire->endTransmission() == SUCCESS );
+#else
+  return false;
+#endif
+}
+
+/**************************************/
+/* ATTEMPT TO WRITE A NUMBER OF BYTES */
+/**************************************/
+// Pass address within EEPROM in address.
+// Pass pointer to buffer of bytes to write in buffer.
+// Pass number of bytes to write in count.
+// Returns true if successful, false if not.
+bool I2CEEPROM::WriteBytes( UInt16 address, const UInt8 *buffer, UInt16 count ) {
+#if 0
+    bool ok = true;
+    // Write enable EEPROM and wait a bit.
+    digitalWrite( wp, LOW );
+    delay( 1 );
+    // Keep writing chunks until all bytes written.
+    while( ( count > 0 ) && ok ) {
+        if( count > CHUNK_SIZE ) {
+            ok = WriteChunk( address, buffer, (UInt8)CHUNK_SIZE );
+            address += CHUNK_SIZE;
+            buffer += CHUNK_SIZE;
+            count -= CHUNK_SIZE;
+        }
+        else {
+            ok = WriteChunk( address, buffer, (UInt8)count );
+            count = 0;
+        }
+        // Wait a lot to allow page to be written.
+        delay( 6 );
+    }
+    // Write protect EEPROM.
+    digitalWrite( wp, HIGH );
+    // Return true on success.
+    return ok;
+#else
+  return false;
+#endif
+}
+