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I2CEEBlockDevice.cpp
- Committer:
- JackB
- Date:
- 2018-07-23
- Revision:
- 0:45d514e74be4
File content as of revision 0:45d514e74be4:
/* 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; }