add example (#7)

Added updateByte() + example + versie 1.3.1

I2C_eeprom.cpp

@@ -1,36 +1,37 @@
 //
 //    FILE: I2C_eeprom.cpp
 //  AUTHOR: Rob Tillaart
-// VERSION: 1.3.0
+// VERSION: 1.3.1
 // PURPOSE: Arduino Library for external I2C EEPROM 24LC256 et al.
 //     URL: https://github.com/RobTillaart/I2C_EEPROM.git
 //
 // HISTORY:
-// 0.1.00 - 2011-01-21 initial version
-// 0.1.01 - 2011-02-07 added setBlock function
-// 0.2.00 - 2011-02-11 fixed 64 bit boundary bug
-// 0.2.01 - 2011-08-13 _readBlock made more robust + return value
-// 1.0.00 - 2013-06-09 support for Arduino 1.0.x
-// 1.0.01 - 2013-11-01 fixed writeBlock bug, refactor
-// 1.0.02 - 2013-11-03 optimize internal buffers, refactor
-// 1.0.03 - 2013-11-03 refactor 5 millis() write-latency
-// 1.0.04 - 2013-11-03 fix bug in readBlock, moved waitEEReady()
-//                     -> more efficient.
-// 1.0.05 - 2013-11-06 improved waitEEReady(),
-//                     added determineSize()
-// 1.1.00 - 2013-11-13 added begin() function (Note breaking interface)
-//                     use faster block Wire.write()
-//                     int casting removed
-// 1.2.00 - 2014-05-21 Added support for Arduino DUE ( thanks to Tyler F.)
-// 1.2.01 - 2014-05-21 Refactoring
-// 1.2.02 - 2015-03-06 stricter interface
-// 1.2.03 - 2015-05-15 bugfix in _pageBlock & example (thanks ifreislich )
-// 1.2.4    2017-04-19 remove timeout - issue #63
-// 1.2.5    2017-04-20 refactor the removed timeout (Thanks to Koepel)
-// 1.2.6    2019-02-01 fix issue #121
-// 1.2.7    2019-09-03 fix issue #113 and #128
-// 1.3.0    2020-06-19 refactor; removed pre 1.0 support; added ESP32 support.
-//
+// 0.1.00 - 2011-01-21  initial version
+// 0.1.01 - 2011-02-07  added setBlock function
+// 0.2.00 - 2011-02-11  fixed 64 bit boundary bug
+// 0.2.01 - 2011-08-13  _readBlock made more robust + return value
+// 1.0.00 - 2013-06-09  support for Arduino 1.0.x
+// 1.0.01 - 2013-11-01  fixed writeBlock bug, refactor
+// 1.0.02 - 2013-11-03  optimize internal buffers, refactor
+// 1.0.03 - 2013-11-03  refactor 5 millis() write-latency
+// 1.0.04 - 2013-11-03  fix bug in readBlock, moved waitEEReady()
+//                      -> more efficient.
+// 1.0.05 - 2013-11-06  improved waitEEReady(),
+//                      added determineSize()
+// 1.1.00 - 2013-11-13  added begin() function (Note breaking interface)
+//                      use faster block Wire.write()
+//                      int casting removed
+// 1.2.00 - 2014-05-21  Added support for Arduino DUE ( thanks to Tyler F.)
+// 1.2.01 - 2014-05-21  Refactoring
+// 1.2.02 - 2015-03-06  stricter interface
+// 1.2.03 - 2015-05-15  bugfix in _pageBlock & example (thanks ifreislich )
+// 1.2.4    2017-04-19  remove timeout - issue #63
+// 1.2.5    2017-04-20  refactor the removed timeout (Thanks to Koepel)
+// 1.2.6    2019-02-01  fix issue #121
+// 1.2.7    2019-09-03  fix issue #113 and #128
+// 1.3.0    2020-06-19  refactor; removed pre 1.0 support; added ESP32 support.
+// 1.3.1    2020-12-22  arduino-ci + unit tests + updateByte()
+
 
 #include <I2C_eeprom.h>
 
@@ -124,6 +125,14 @@ uint16_t I2C_eeprom::readBlock(const uint16_t memoryAddress, uint8_t* buffer, co
   return rv;
 }
 
+
+int I2C_eeprom::updateByte(const uint16_t memoryAddress, const uint8_t data)
+{
+  if (data == readByte(memoryAddress)) return 0;
+  return writeByte(memoryAddress, data);
+}
+  
+  
 // returns 64, 32, 16, 8, 4, 2, 1, 0
 // 0 is smaller than 1K
 int I2C_eeprom::determineSize()

I2C_eeprom.h

@@ -2,17 +2,17 @@
 //
 //    FILE: I2C_eeprom.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 1.3.0
+// VERSION: 1.3.1
 // PURPOSE: Arduino Library for external I2C EEPROM 24LC256 et al.
 //     URL: https://github.com/RobTillaart/I2C_EEPROM.git
 //
 // HISTORY: See I2C_eeprom.cpp
 
 
-#include "Wire.h"
 #include "Arduino.h"
+#include "Wire.h"
 
-#define I2C_EEPROM_VERSION "1.3.0"
+#define I2C_EEPROM_VERSION "1.3.1"
 
 // The DEFAULT page size. This is overriden if you use the second constructor.
 // I2C_EEPROM_PAGESIZE must be multiple of 2 e.g. 16, 32 or 64
@@ -47,17 +47,21 @@ public:
   void begin();
 
   // writes a byte to memaddr
-  int writeByte(const uint16_t memoryAddress, const uint8_t value);
+  int      writeByte(const uint16_t memoryAddress, const uint8_t value);
   // writes length bytes from buffer to EEPROM
-  int writeBlock(const uint16_t memoryAddress, const uint8_t* buffer, const uint16_t length);
+  int      writeBlock(const uint16_t memoryAddress, const uint8_t* buffer, const uint16_t length);
   // set length bytes in the EEPROM to the same value.
-  int setBlock(const uint16_t memoryAddress, const uint8_t value, const uint16_t length);
+  int      setBlock(const uint16_t memoryAddress, const uint8_t value, const uint16_t length);
 
   // returns the value stored in memaddr
   uint8_t  readByte(const uint16_t memoryAddress);
   // reads length bytes into buffer
   uint16_t readBlock(const uint16_t memoryAddress, uint8_t* buffer, const uint16_t length);
 
+  // updates a byte at memory address, writes only if there is a new value.
+  // return 0 if data is same or written OK, error code otherwise.
+  int      updateByte(const uint16_t memoryAddress, const uint8_t value);
+
   int      determineSize();
 
 private:

README.md

@@ -20,14 +20,14 @@ The interface is pretty straightforward
 - **setBlock(address, value, length)** e.g. use to clear I2C EEPROM
 - **readByte(address)** - read a single byte from a given address
 - **readBlock(address, buffer, length)**
+- **updateByte(address, value)** write a single byte, but only if changed.
 - **determineSize()**
 
 
 ## Limitation
 
 The library does not offer multiple EEPROMS as one 
-continuous storage device. 
-
+continuous storage device.
 
 ## Operational
 

examples/I2C_eeprom_update/I2C_eeprom_update.ino

@@ -0,0 +1,77 @@
+//
+//    FILE: I2C_eeprom_update.ino
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.1.0
+// PURPOSE: demo I2C_EEPROM library - updateByte
+//
+
+#include <Wire.h>
+#include <I2C_eeprom.h>
+
+#define MEMORY_SIZE 0x2000 // total bytes can be accessed 24LC64 = 0x2000 (maximum address = 0x1FFF)
+
+I2C_eeprom ee(0x50, MEMORY_SIZE);
+
+uint32_t start, dur1, dur2;
+
+void setup() 
+{
+  ee.begin();
+  Serial.begin(115200); 
+  while (!Serial); // wait for SERIAL_OUT port to connect. Needed for Leonardo only
+
+  Serial.println(__FILE__);
+  Serial.print("VERSION: ");
+  Serial.println(I2C_EEPROM_VERSION);
+
+  Serial.println("\nTEST: determine size");
+  int size = ee.determineSize();
+  if (size > 0)
+  {
+    Serial.print("SIZE: ");
+    Serial.print(size);
+    Serial.println(" KB");
+  } 
+  else if (size == 0)
+  {
+    Serial.println("WARNING: Can't determine eeprom size");
+  }
+  else
+  {
+    Serial.println("ERROR: Can't find eeprom\nstopped...");
+    while(1);
+  }
+
+  Serial.println("\nTEST: 100x writebyte()");
+  delay(10);
+  ee.setBlock(0, 0, 100);  // clear first 100 bytes
+  start = micros();
+  for (int i = 0; i < 100; i++)
+  {
+    ee.writeByte(i, 0);
+  }
+  dur1 = micros() - start;
+  Serial.print("DUR1: ");
+  Serial.println(dur1);
+  delay(10);
+  
+  Serial.println("\nTEST: 100x updateByte()");
+  ee.setBlock(0, 0, 100);  // clear first 100 bytes
+  start = micros();
+  for (int i = 0; i < 100; i++)
+  {
+    ee.updateByte(i, 0);
+  }
+  dur2 = micros() - start;
+  Serial.print("DUR2: ");
+  Serial.println(dur2);
+  delay(10);
+  
+  Serial.println("done...");
+}
+
+void loop() 
+{
+}
+
+// -- END OF FILE

keywords.txt

@@ -10,5 +10,6 @@ setBlock	KEYWORD2
 readBlock	KEYWORD2
 writeBlock	KEYWORD2
 determineSize	KEYWORD2
+updateByte	KEYWORD2
 
 # Constants (LITERAL1)

library.json

@@ -15,7 +15,7 @@
     "type": "git",
     "url": "https://github.com/RobTillaart/I2C_EEPROM.git"
   },
-  "version":"1.3.0",
+  "version":"1.3.1",
   "frameworks": "arduino",
   "platforms": "*"
 }

library.properties

@@ -1,5 +1,5 @@
 name=I2C_EEPROM
-version=1.3.0
+version=1.3.1
 author=Rob Tillaart <rob.tillaart@gmail.com>
 maintainer=Rob Tillaart <rob.tillaart@gmail.com>
 sentence=Library for I2C EEPROMS. 
@@ -8,4 +8,4 @@ category=Data Storage
 url=https://github.com/RobTillaart/I2C_EEPROM.git
 architectures=*
 includes=I2C_eeprom.h
-depends=
+depends=

test/unit_test_001.cpp

@@ -56,7 +56,7 @@ unittest(test_new_operator)
 
 unittest(test_constructor)
 {
-  I2C_eeprom EE(48);
+  I2C_eeprom EE(0x50);
   EE.begin();