Revision 1:b23f5561266c, committed 2015-07-19

Comitter:

rhourahane

Date:

Sun Jul 19 09:34:04 2015 +0000

Parent:

0:f275a33797f1

Commit message:

Updates to make library more generic to allow support for more I2C EEPROM chips.

Changed in this revision

diff -r f275a33797f1 -r b23f5561266c I2CEeprom.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/I2CEeprom.cpp	Sun Jul 19 09:34:04 2015 +0000
@@ -0,0 +1,198 @@
+/* Simple access class for I2C EEPROM chips like Microchip 24LC
+ * Copyright (c) 2015 Robin Hourahane
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "I2CEeprom.h"
+
+I2CEeprom::I2CEeprom(PinName sda, PinName scl, int address, size_t pageSize, size_t chipSize, int busSpeed):
+    m_i2c(sda, scl),
+    m_i2cAddress(address),
+    m_chipSize(chipSize),
+    m_pageSize(pageSize)
+{
+    m_i2c.frequency(busSpeed);
+}
+
+size_t I2CEeprom::read(size_t address, char &value) {
+    // Check the address and size fit onto the chip.
+    if (!checkSpace(address, 1))
+        return 0;
+        
+    char values[] = { (address >> 8), (address & 0xFF) };
+    if (m_i2c.write(m_i2cAddress, values, 2) == 0) {
+        if (m_i2c.read(m_i2cAddress, &value, 1) == 0) {
+            return 1;
+        }
+    }
+    
+    return 0;
+}
+
+size_t I2CEeprom::read(size_t address, char *buffer, size_t size) {
+    // Check the address and size fit onto the chip.
+    if (!checkSpace(address, size))
+        return 0;
+        
+    char values[] = { (address >> 8), (address & 0xFF) };
+    if (m_i2c.write(m_i2cAddress, values, 2) == 0) {
+        if (m_i2c.read(m_i2cAddress, buffer, size) == 0) {
+            return size;
+        }
+    }
+    
+    return 0;
+}
+
+size_t I2CEeprom::write(size_t address, char value) {
+    // Check the address and size fit onto the chip.
+    if (!checkSpace(address, 1))
+        return 0;
+        
+    char values[] = { (address >> 8), (address & 0xFF), value };
+    if (m_i2c.write(m_i2cAddress, values, 3) != 0) {
+        return 0;
+    }
+    
+    waitForWrite();
+    
+    return 1;
+}
+
+size_t I2CEeprom::write(size_t address, const char *buffer, size_t size) {
+    // Check the address and size fit onto the chip.
+    if (!checkSpace(address, size))
+        return 0;
+        
+    const char *page = buffer;
+    size_t left = size;
+    
+    // Whle we have some more data to write.
+    while (left != 0) {
+        // Calculate the number of bytes we can write in the current page.
+        // If the address is not page aligned then write enough to page 
+        // align it.
+        size_t toWrite;
+        if ((address % m_pageSize) != 0) {
+            toWrite = (((address / m_pageSize) + 1) * m_pageSize) - address;
+            if (toWrite > size) {
+                toWrite = size;
+            }
+        } else {
+            if (left <= m_pageSize) {
+                toWrite = left;
+            } else {
+                toWrite = m_pageSize;
+            }
+        }
+        
+        //printf("Writing [%.*s] at %d size %d\n\r", toWrite, page, address, toWrite);
+        // Start the page write with the addres ine one write call.
+        char values[] = { (address >> 8), (address & 0xFF) };
+        if (m_i2c.write(m_i2cAddress, values, 2, true) != 0) {
+            // Write failed to return bytes written so far.
+            return size - left;
+        }
+
+        // Write the bytes out one at a time to avoid having to copy them to
+        // another buffer.        
+        for (int count = 0; count != toWrite; ++count) {
+            if (m_i2c.write(*page) == 0) {
+            // Write failed to return bytes written so far.
+                return size - left;
+            }
+            ++page;
+        }
+        
+        // Stop the transaction now we've completed the page
+        // write.
+        m_i2c.stop();
+        
+        waitForWrite();
+        
+        // Update the counters with the amount we've just written
+        left -= toWrite;
+        address += toWrite;
+    }
+    
+    return size;
+}
+
+size_t I2CEeprom::fill(size_t address, char value, size_t size) {
+    // Check the address and size fit onto the chip.
+    if (!checkSpace(address, size))
+        return 0;
+        
+    size_t left = size;
+    
+    while (left != 0) {
+        size_t toWrite;
+        if ((address % m_pageSize) != 0) {
+            toWrite = (((address / m_pageSize) + 1) * 64) - address;
+            if (toWrite > size) {
+                toWrite = size;
+            }
+        } else {
+            if (left <= m_pageSize) {
+                toWrite = left;
+            } else {
+                toWrite = m_pageSize;
+            }
+        }
+        
+        //printf("Writing %d at %d size %d\n\r", value, address, toWrite);
+        char values[] = { (address >> 8), (address & 0xFF) };
+        if (m_i2c.write(m_i2cAddress, values, 2, true) != 0) {
+            return size - left;
+        }
+        
+        for (int count = 0; count != toWrite; ++count) {
+            if (m_i2c.write(value) == 0)
+                return size - left;
+        }
+        
+        m_i2c.stop();
+        
+        waitForWrite();
+        
+        left -= toWrite;
+        address += toWrite;
+    }
+    
+    return size;
+}
+
+void I2CEeprom::waitForWrite() {
+    // The chip doesn't ACK while writing to the actual EEPROM
+    // so loop trying to do a zero byte write until it is ACKed
+    // by the chip.
+    while (m_i2c.write(m_i2cAddress, 0, 0) != 0) {
+        // Wait for ack.
+        wait_ms(1);
+    }
+}
+
+bool I2CEeprom::checkSpace(size_t address, size_t size) {
+    // Only check if chip size is non-zero.
+    if (m_chipSize != 0) {
+        // Check that the address start in the chip and doesn't
+        // extend past.
+        if ((address >= m_chipSize) || ((address + size) >= m_chipSize))
+            return false;
+        else
+            return true;
+    }
+    
+    return true;
+}
+

diff -r f275a33797f1 -r b23f5561266c I2CEeprom.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/I2CEeprom.h	Sun Jul 19 09:34:04 2015 +0000
@@ -0,0 +1,108 @@
+/* Simple access class for I2C EEPROM chips like Microchip 24LC
+ * Copyright (c) 2015 Robin Hourahane
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef __I2CEEPROM_H__
+#define __I2CEEPROM_H__
+
+#include <mbed.h>
+
+/// Class to provide simple access to I2C EEPROM chiles like Microchip's 24LC range
+/// or AMTELS AT24C range.
+/// Chips up to 64Kb in size are directly supported.
+/// The class handles multiple page writes so any amount of data can be written in
+/// a single call to write. The writes are not buffered so additional memory use 
+/// is kept to a minimum.
+///
+/// Although not tested it should work with the MAC versions of Microchip range
+/// as well but the chipSize will need to be set to include the ROM area as well.
+class I2CEeprom {
+public:
+    /// Constructor to create a new instance of the class.
+    /// @param sda The pin name for the sda line of the I2C bus.
+    /// @param scl The pin name for the scl line of the I2C bus.
+    /// @param address The 8bit I2C address of the chip in the range 0xA0 - 0xAE.
+    /// @param pageSize The size of the page used in writing to the chip.
+    /// @param chipSize The size of the memory in the chip to allow range checkng. Set to
+    /// 0 to disable checks.
+    /// @param busSpeed The frequency of the I2C bus defaults to 400K.
+    I2CEeprom(PinName sda, PinName scl, int address, size_t pageSize, size_t chipSize, int busSpeed = 400000);
+    
+    /// Read a single byte from the address in memory.
+    /// @param address Memory address to read from.
+    /// @param value Variable to receive value read.
+    /// @returns Number of bytes read from memory.
+    size_t read(size_t address, char &value);
+    
+    /// Read multiple bytes starting from the address in memory.
+    /// @param address Memory address to start reading from.
+    /// @param buffer Pointer to buffer to hold bytes read from memory.
+    /// @param size Number of bytes to be read from memory.
+    /// @returns Number of bytes read from memory.
+    size_t read(size_t address, char *buffer, size_t size);
+    
+    /// Read either an instance or an array of a POD type from memory.
+    /// Note the value of the type can't contain pointers.
+    /// @param address Start address for reading memory.
+    /// @param value Object to be read from memory.
+    /// @returns Number of bytes read from memory.
+    template<typename T> size_t read(size_t address, T &value) {
+        return read(address, reinterpret_cast<char *>(&value), sizeof(T));
+    }
+    
+    /// Write a single byte to the address in memory.
+    /// @param address Memory address to write to.
+    /// @param value Value to be written to memory.
+    /// @returns Number of bytes written to memory.
+    size_t write(size_t address, char value);
+
+    /// Write multiple bytes starting from the address in memory.
+    /// @param address Memory address to start writting to.
+    /// @param buffer Pointer to buffer holding the bytes to write to memory.
+    /// @param size Number of bytes to be written to memory.
+    /// @returns Number of bytes written to memory.
+    size_t write(size_t address, const char *buffer, size_t size);
+    
+    /// Write either an instance or an array of a POD type to memory.
+    /// Note the value of the type can't contain pointers.
+    /// @param address Start address to write to memory.
+    /// @returns Number of bytes written to memory.
+    template<typename T> size_t write(size_t address, const T &value) {
+        return write(address, reinterpret_cast<const char *>(&value), sizeof(T));
+    }
+    
+    /// Fill a range of memory with a single value. No memory is allocated
+    /// so large areas can be filled with minimal memory usage.
+    /// @param address Starting address to write to.
+    /// @param value Value to be written to memory.
+    /// @Param size Number of bytes to be written.
+    /// @returns Number of bytes written to memory.
+    size_t fill(size_t address, char value, size_t size);
+    
+private:
+    // Wait for a write cycle to complete using polling and small waits.
+    void waitForWrite();
+    
+    // Validate that the proposed opperation will fit in the size of
+    // the chip.
+    bool checkSpace(size_t address, size_t size);
+    
+private:
+    I2C m_i2c;
+    int m_i2cAddress;
+    size_t m_chipSize;
+    size_t m_pageSize;
+};
+
+#endif
\ No newline at end of file

diff -r f275a33797f1 -r b23f5561266c Mem24LCXX.cpp
--- a/Mem24LCXX.cpp	Sat Jun 27 13:03:49 2015 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,170 +0,0 @@
-/* Simple access class for Microchip 24LC EEPROM chips library
- * Copyright (c) 2015 Robin Hourahane
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-#include "Mem24LCXX.h"
-
-const int PageSize = 64;
-
-Mem24LCXX::Mem24LCXX(PinName sda, PinName scl, int address, size_t chipSize, int busSpeed):
-    m_i2c(sda, scl),
-    m_i2cAddress(address),
-    m_chipSize(chipSize)
-{
-    m_i2c.frequency(busSpeed);
-}
-
-size_t Mem24LCXX::read(size_t address, char &value) {
-    if (!checkSpace(address, 1))
-        return 0;
-        
-    char values[] = { (address >> 8), (address & 0xFF) };
-    if (m_i2c.write(m_i2cAddress, values, 2) == 0) {
-        if (m_i2c.read(m_i2cAddress, &value, 1) == 0) {
-            return 1;
-        }
-    }
-    
-    return 0;
-}
-
-size_t Mem24LCXX::read(size_t address, char *buffer, size_t size) {
-    if (!checkSpace(address, size))
-        return 0;
-        
-    char values[] = { (address >> 8), (address & 0xFF) };
-    if (m_i2c.write(m_i2cAddress, values, 2) == 0) {
-        if (m_i2c.read(m_i2cAddress, buffer, size) == 0) {
-            return size;
-        }
-    }
-    
-    return 0;
-}
-
-size_t Mem24LCXX::write(size_t address, char value) {
-    if (!checkSpace(address, 1))
-        return 0;
-        
-    char values[] = { (address >> 8), (address & 0xFF), value };
-    if (m_i2c.write(m_i2cAddress, values, 3) != 0) {
-        return 0;
-    }
-    
-    waitForWrite();
-    
-    return 1;
-}
-
-size_t Mem24LCXX::write(size_t address, const char *buffer, size_t size) {
-    if (!checkSpace(address, size))
-        return 0;
-        
-    const char *page = buffer;
-    size_t left = size;
-    
-    while (left != 0) {
-        size_t toWrite;
-        if ((address % PageSize) != 0) {
-            toWrite = (((address / PageSize) + 1) * 64) - address;
-            if (toWrite > size) {
-                toWrite = size;
-            }
-        } else {
-            if (left <= PageSize) {
-                toWrite = left;
-            } else {
-                toWrite = PageSize;
-            }
-        }
-        
-        printf("Writing [%.*s] at %d size %d\n\r", toWrite, page, address, toWrite);
-        char values[] = { (address >> 8), (address & 0xFF) };
-        if (m_i2c.write(m_i2cAddress, values, 2, true) != 0) {
-            return size - left;
-        }
-        
-        for (int count = 0; count != toWrite; ++count) {
-            if (m_i2c.write(*page) == 0) {
-                return size - left;
-            }
-            ++page;
-        }
-        
-        m_i2c.stop();
-        
-        waitForWrite();
-        
-        left -= toWrite;
-        address += toWrite;
-    }
-    return size;
-}
-
-size_t Mem24LCXX::fill(size_t address, char value, size_t size) {
-    if (!checkSpace(address, size))
-        return 0;
-        
-    size_t left = size;
-    
-    while (left != 0) {
-        size_t toWrite;
-        if ((address % PageSize) != 0) {
-            toWrite = (((address / PageSize) + 1) * 64) - address;
-            if (toWrite > size) {
-                toWrite = size;
-            }
-        } else {
-            if (left <= PageSize) {
-                toWrite = left;
-            } else {
-                toWrite = PageSize;
-            }
-        }
-        
-        printf("Writing %d at %d size %d\n\r", value, address, toWrite);
-        char values[] = { (address >> 8), (address & 0xFF) };
-        if (m_i2c.write(m_i2cAddress, values, 2, true) != 0) {
-            return size - left;
-        }
-        
-        for (int count = 0; count != toWrite; ++count) {
-            if (m_i2c.write(value) == 0)
-                return size - left;
-        }
-        
-        m_i2c.stop();
-        
-        waitForWrite();
-        
-        left -= toWrite;
-        address += toWrite;
-    }
-    return true;
-}
-
-void Mem24LCXX::waitForWrite() {
-    while (m_i2c.write(m_i2cAddress, 0, 0) != 0) {
-        // Wait for ack.
-        wait_ms(1);
-    }
-}
-
-bool Mem24LCXX::checkSpace(size_t address, size_t size) {
-    if ((address >= m_chipSize) || ((address + size) >= m_chipSize))
-        return false;
-    else
-        return true;
-}
-

diff -r f275a33797f1 -r b23f5561266c Mem24LCXX.h
--- a/Mem24LCXX.h	Sat Jun 27 13:03:49 2015 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,105 +0,0 @@
-/* Simple access class for Microchip 24LC EEPROM chips library
- * Copyright (c) 2015 Robin Hourahane
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-#ifndef __MEM24LCXX_H__
-#define __MEM24LCXX_H__
-
-#include <mbed.h>
-
-/// Class to provide simple access to Microchip's 24LC range of I2C EEPROM memory chips.
-/// Chips up to 64Kb in size are directly supported, the bank selected 128Kb chips
-/// can be handled by creating to instances of the class one for each bank.
-/// The class handles multiple page writes so any amount of data can be written in
-/// a single call to write. The writes are not buffered so additional memory use 
-/// is kept to a minimum.
-///
-/// Although not tested it should work with the MAC versions as well but the chipSize will
-/// need to be set to include the ROM area as well.
-class Mem24LCXX {
-public:
-    /// Constructor to create a new instance of the class.
-    /// @param sda The pin name for the sda line of the I2C bus.
-    /// @param scl The pin name for the scl line of the I2C bus.
-    /// @param address The 8bit I2C address of the chip in the range 0xA0 - 0xAE.
-    /// @param chipSize The size of the memory in the chip to allow range checkng.
-    /// @param busSpeed The frequency of the I2C bus defaults to 400K.
-    Mem24LCXX(PinName sda, PinName scl, int address, size_t chipSize, int busSpeed = 400000);
-    
-    /// Read a single byte from the address in memory.
-    /// @param address Memory address to read from.
-    /// @param value Variable to receive value read.
-    /// @returns Number of bytes read from memory.
-    size_t read(size_t address, char &value);
-    
-    /// Read multiple bytes starting from the address in memory.
-    /// @param address Memory address to start reading from.
-    /// @param buffer Pointer to buffer to hold bytes read from memory.
-    /// @param size Number of bytes to be read from memory.
-    /// @returns Number of bytes read from memory.
-    size_t read(size_t address, char *buffer, size_t size);
-    
-    /// Read either an instance or an array of a POD type from memory.
-    /// Note the value of the type can't contain pointers.
-    /// @param address Start address for reading memory.
-    /// @param value Object to be read from memory.
-    /// @returns Number of bytes read from memory.
-    template<typename T> size_t read(size_t address, T &value) {
-        return read(address, reinterpret_cast<char *>(&value), sizeof(T));
-    }
-    
-    /// Write a single byte to the address in memory.
-    /// @param address Memory address to write to.
-    /// @param value Value to be written to memory.
-    /// @returns Number of bytes written to memory.
-    size_t write(size_t address, char value);
-
-    /// Write multiple bytes starting from the address in memory.
-    /// @param address Memory address to start writting to.
-    /// @param buffer Pointer to buffer holding the bytes to write to memory.
-    /// @param size Number of bytes to be written to memory.
-    /// @returns Number of bytes written to memory.
-    size_t write(size_t address, const char *buffer, size_t size);
-    
-    /// Write either an instance or an array of a POD type to memory.
-    /// Note the value of the type can't contain pointers.
-    /// @param address Start address to write to memory.
-    /// @returns Number of bytes written to memory.
-    template<typename T> size_t write(size_t address, const T &value) {
-        return write(address, reinterpret_cast<const char *>(&value), sizeof(T));
-    }
-    
-    /// Fill a range of memory with a single value. No memory is allocated
-    /// so large areas can be filled with minimal memory usage.
-    /// @param address Starting address to write to.
-    /// @param value Value to be written to memory.
-    /// @Param size Number of bytes to be written.
-    /// @returns Number of bytes written to memory.
-    size_t fill(size_t address, char value, size_t size);
-    
-private:
-    // Wait for a write cycle to complete using polling and small waits.
-    void waitForWrite();
-    
-    // Validate that the proposed opperation will fit in the size of
-    // the chip.
-    bool checkSpace(size_t address, size_t size);
-    
-private:
-    I2C m_i2c;
-    int m_i2cAddress;
-    size_t m_chipSize;
-};
-
-#endif
\ No newline at end of file