Diff: I2CEEBlockDevice.cpp

Revision:

0:45d514e74be4

--- /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;
+}