Revision 0:45d514e74be4, committed 2018-07-23

Comitter:

JackB

Date:

Mon Jul 23 12:23:08 2018 +0000

Commit message:

I2CEE

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/I2CEEBlockDevice.cpp	Mon Jul 23 12:23:08 2018 +0000
@@ -0,0 +1,134 @@
+/* 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 "I2CEEBlockDevice.h"
+
+#define I2CEE_TIMEOUT 10000
+ 
+
+I2CEEBlockDevice::I2CEEBlockDevice(
+        PinName sda, PinName scl, uint8_t addr,
+        bd_size_t size, bd_size_t block, int freq)
+    : _i2c(sda, scl), _i2c_addr(addr), _size(size), _block(block)
+{
+    _i2c.frequency(freq);
+}
+
+int I2CEEBlockDevice::init()
+{
+    return _sync();
+}
+
+int I2CEEBlockDevice::deinit()
+{
+    return 0;
+}
+
+int I2CEEBlockDevice::read(void *buffer, bd_addr_t addr, bd_size_t size)
+{
+    // Check the address and size fit onto the chip.
+    MBED_ASSERT(is_valid_read(addr, size));
+
+    _i2c.start();
+    if (!_i2c.write(_i2c_addr | 0) ||
+        !_i2c.write((char)(addr >> 8)) ||
+        !_i2c.write((char)(addr & 0xff))) {
+        return BD_ERROR_DEVICE_ERROR;
+    }
+    _i2c.stop();
+
+    if (_i2c.read(_i2c_addr, static_cast<char*>(buffer), size) < 0) {
+        return BD_ERROR_DEVICE_ERROR;
+    }
+
+    return 0;
+}
+ 
+int I2CEEBlockDevice::program(const void *buffer, bd_addr_t addr, bd_size_t size)
+{
+    // Check the addr and size fit onto the chip.
+    MBED_ASSERT(is_valid_program(addr, size));
+        
+    // While we have some more data to write.
+    while (size > 0) {
+        uint32_t off = addr % _block;
+        uint32_t chunk = (off + size < _block) ? size : (_block - off);
+
+        _i2c.start();
+        if (!_i2c.write(_i2c_addr | 0) ||
+            !_i2c.write((char)(addr >> 8)) ||
+            !_i2c.write((char)(addr & 0xff))) {
+            return BD_ERROR_DEVICE_ERROR;
+        }
+
+        for (unsigned i = 0; i < chunk; i++) {
+            _i2c.write(static_cast<const char*>(buffer)[i]);
+        }
+        _i2c.stop();
+
+        int err = _sync();
+        if (err) {
+            return err;
+        }
+
+        addr += chunk;
+        size -= chunk;
+        buffer = static_cast<const char*>(buffer) + chunk;
+    }
+
+    return 0;
+}
+
+int I2CEEBlockDevice::erase(bd_addr_t addr, bd_size_t size)
+{
+    // No erase needed
+    return 0;
+}
+
+int I2CEEBlockDevice::_sync()
+{
+    // 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.
+    for (int i = 0; i < I2CEE_TIMEOUT; i++) {
+        if (_i2c.write(_i2c_addr | 0, 0, 0) < 1) {
+            return 0;
+        }
+
+        wait_ms(1);
+    }
+
+    return BD_ERROR_DEVICE_ERROR;
+}
+ 
+bd_size_t I2CEEBlockDevice::get_read_size() const
+{
+    return 1;
+}
+
+bd_size_t I2CEEBlockDevice::get_program_size() const
+{
+    return 1;
+}
+
+bd_size_t I2CEEBlockDevice::get_erase_size() const
+{
+    return 1;
+}
+
+bd_size_t I2CEEBlockDevice::size() const
+{
+    return _size;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/I2CEEBlockDevice.h	Mon Jul 23 12:23:08 2018 +0000
@@ -0,0 +1,153 @@
+/* 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 MBED_I2CEEPROM_BLOCK_DEVICE_H
+#define MBED_I2CEEPROM_BLOCK_DEVICE_H
+ 
+#include <mbed.h>
+#include "BlockDevice.h"
+
+ 
+/** BlockDevice for I2C based flash device such as
+ *  Microchip's 24LC or ATMEL's AT24C ranges
+ *
+ *  @code
+ *  // Here's an example using a 24LC256 on a GR PEACH
+ *  #include "mbed.h"
+ *  #include "I2CEEBlockDevice.h"
+ *  
+ *  // Create EEPROM device on I2C bus with 32kbytes of memory
+ *  I2CEEBlockDevice i2cee(D14, D15, 0xa0, 32*1024);
+ *  
+ *  int main() {
+ *      printf("i2cee test\n");
+ *  
+ *      // Initialize the device and print the memory layout
+ *      i2cee.init();
+ *      printf("i2cee size: %llu\n",         i2cee.size());
+ *      printf("i2cee read size: %llu\n",    i2cee.get_read_size());
+ *      printf("i2cee program size: %llu\n", i2cee.get_program_size());
+ *      printf("i2cee erase size: %llu\n",   i2cee.get_erase_size());
+ *  
+ *      // Write "Hello World!" to the first block
+ *      char *buffer = (char*)malloc(i2cee.get_erase_size());
+ *      sprintf(buffer, "Hello World!\n");
+ *      i2cee.erase(0, i2cee.get_erase_size());
+ *      i2cee.program(buffer, 0, i2cee.get_erase_size());
+ *  
+ *      // Read back what was stored
+ *      i2cee.read(buffer, 0, i2cee.get_erase_size());
+ *      printf("%s", buffer);
+ *  
+ *      // Deinitialize the device
+ *      i2cee.deinit();
+ *  }
+ *  @endcode
+ */
+class I2CEEBlockDevice : public BlockDevice {
+public:
+    /** Constructor to create an I2CEEBlockDevice on I2C pins
+     *
+     *  @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 addr     The 8bit I2C address of the chip, common range 0xa0 - 0xae.
+     *  @param size     The size of the device in bytes
+     *  @param block    The page size of the device in bytes, defaults to 32bytes
+     *  @param freq     The frequency of the I2C bus, defaults to 400K.
+     */
+    I2CEEBlockDevice(
+            PinName sda, PinName scl, uint8_t address,
+            bd_size_t size, bd_size_t block=32,
+            int bus_speed=400000);
+
+    /** Initialize a block device
+     *
+     *  @return         0 on success or a negative error code on failure
+     */
+    virtual int init();
+
+    /** Deinitialize a block device
+     *
+     *  @return         0 on success or a negative error code on failure
+     */
+    virtual int deinit();
+
+    /** Read blocks from a block device
+     *
+     *  @param buffer   Buffer to write blocks to
+     *  @param addr     Address of block to begin reading from
+     *  @param size     Size to read in bytes, must be a multiple of read block size
+     *  @return         0 on success, negative error code on failure
+     */
+    virtual int read(void *buffer, bd_addr_t addr, bd_size_t size);
+
+    /** Program blocks to a block device
+     *
+     *  The blocks must have been erased prior to being programmed
+     *
+     *  @param buffer   Buffer of data to write to blocks
+     *  @param addr     Address of block to begin writing to
+     *  @param size     Size to write in bytes, must be a multiple of program block size
+     *  @return         0 on success, negative error code on failure
+     */
+    virtual int program(const void *buffer, bd_addr_t addr, bd_size_t size);
+
+    /** Erase blocks on a block device
+     *
+     *  The state of an erased block is undefined until it has been programmed
+     *
+     *  @param addr     Address of block to begin erasing
+     *  @param size     Size to erase in bytes, must be a multiple of erase block size
+     *  @return         0 on success, negative error code on failure
+     */
+    virtual int erase(bd_addr_t addr, bd_size_t size);
+
+    /** Get the size of a readable block
+     *
+     *  @return         Size of a readable block in bytes
+     */
+    virtual bd_size_t get_read_size() const;
+
+    /** Get the size of a programable block
+     *
+     *  @return         Size of a programable block in bytes
+     *  @note Must be a multiple of the read size
+     */
+    virtual bd_size_t get_program_size() const;
+
+    /** Get the size of a eraseable block
+     *
+     *  @return         Size of a eraseable block in bytes
+     *  @note Must be a multiple of the program size
+     */
+    virtual bd_size_t get_erase_size() const;
+
+    /** Get the total size of the underlying device
+     *
+     *  @return         Size of the underlying device in bytes
+     */
+    virtual bd_size_t size() const;
+    
+private:
+    I2C _i2c;
+    uint8_t _i2c_addr;
+    uint32_t _size;
+    uint32_t _block;
+
+    int _sync();
+};
+ 
+
+#endif  /* MBED_I2CEEPROM_BLOCK_DEVICE_H */