/* Simple access class for I2C EEPROM chips like Microchip 24LC * Copyright (c) 2015 Robin Hourahane * SPDX-License-Identifier: Apache-2.0 * * 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" #include "rtos/ThisThread.h" #include "mbed_wait_api.h" using namespace mbed; using namespace std::chrono_literals; #define I2CEE_TIMEOUT 10000 I2CEEBlockDevice::I2CEEBlockDevice( PinName sda, PinName scl, uint8_t addr, bd_size_t size, bd_size_t block, int freq, bool address_is_eight_bit) : _i2c_addr(addr) , _address_is_eight_bit(address_is_eight_bit) , _size(size) , _block(block) { _i2c = new (_i2c_buffer) I2C(sda, scl); _i2c->frequency(freq); } I2CEEBlockDevice::I2CEEBlockDevice( I2C *i2c_obj, uint8_t addr, bd_size_t size, bd_size_t block, bool address_is_eight_bit) : _i2c_addr(addr) , _address_is_eight_bit(address_is_eight_bit) , _size(size) , _block(block) { _i2c = i2c_obj; } I2CEEBlockDevice::~I2CEEBlockDevice() { if (_i2c == (I2C *)_i2c_buffer) { _i2c->~I2C(); } } 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)); auto *pBuffer = static_cast<char *>(buffer); _i2c->start(); if (I2C::ACK != _i2c->write_byte(get_paged_device_address(addr))) { _i2c->stop(); return BD_ERROR_DEVICE_ERROR; } if (!_address_is_eight_bit && I2C::ACK != _i2c->write_byte((char)(addr >> 8u))) { _i2c->stop(); return BD_ERROR_DEVICE_ERROR; } if (I2C::ACK != _i2c->write_byte((char)(addr & 0xffu))) { _i2c->stop(); return BD_ERROR_DEVICE_ERROR; } // Note: We do not send an I2C stop in this case, because we will do a repeated start in the next // call. if (I2C::ACK != _i2c->read(_i2c_addr | 1, pBuffer, static_cast<int>(size))) { return BD_ERROR_DEVICE_ERROR; } return BD_ERROR_OK; } 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)); const auto *pBuffer = static_cast<const char *>(buffer); // 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::ACK != _i2c->write_byte(get_paged_device_address(addr))) { _i2c->stop(); return BD_ERROR_DEVICE_ERROR; } if (!_address_is_eight_bit && I2C::ACK != _i2c->write_byte((char)(addr >> 8u))) { _i2c->stop(); return BD_ERROR_DEVICE_ERROR; } if (I2C::ACK != _i2c->write_byte((char)(addr & 0xffu))) { _i2c->stop(); return BD_ERROR_DEVICE_ERROR; } for (unsigned i = 0; i < chunk; i++) { if (I2C::ACK != _i2c->write_byte(pBuffer[i])) { _i2c->stop(); return BD_ERROR_DEVICE_ERROR; } } _i2c->stop(); int err = _sync(); if (err) { return err; } addr += chunk; size -= chunk; pBuffer += chunk; } return BD_ERROR_OK; } 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) == I2C::ACK) { return 0; } wait_us(100); } 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; } const char *I2CEEBlockDevice::get_type() const { return "I2CEE"; } uint8_t I2CEEBlockDevice::get_paged_device_address(bd_addr_t address) { if (!_address_is_eight_bit) { return _i2c_addr; } else { // Use the three least significant bits of the 2nd byte as the page // The page will be bits 2-4 of the user defined addresses. return _i2c_addr | ((address & 0x0700u) >> 7u); } }