NFCEEPROM.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2018 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 
00017 #ifndef MBED_NFC_EEPROM_H
00018 #define MBED_NFC_EEPROM_H
00019 
00020 #include <stdint.h>
00021 #include "events/EventQueue.h"
00022 
00023 #include "NFCDefinitions.h"
00024 #include "NFCTarget.h"
00025 #include "NFCEEPROMDriver.h"
00026 
00027 namespace mbed {
00028 namespace nfc {
00029 
00030 /** @addtogroup nfc
00031  * @{
00032  */
00033 
00034 /**
00035  * The NFC EEPROM class represents a NFC target device connected using a wired
00036  * link (I2C, SPI, etc).
00037  *
00038  * These EEPROMs essentially provide addressable memory that can be accessed
00039  * using either a wired or NFC interface.
00040  *
00041  * In NFC mode these most often conform to one of the NFC tag types defined
00042  * by the NFC Forum, therefore encoding NDEF data in these EEPROMs will
00043  * ensure that it is understandable by a NFC reader.
00044  */
00045 class NFCEEPROM : public NFCTarget, public NFCEEPROMDriver::Delegate {
00046 public:
00047     /**
00048      * Construct a NFCEEPROM instance.
00049      *
00050      * @param[in] driver a pointer to a NFCEEPROMDriver instance
00051      * @param[in] queue a pointer to the events queue to use
00052      * @param[in] ndef_buffer a bytes array used to store NDEF messages
00053      */
00054     NFCEEPROM(NFCEEPROMDriver *driver, events::EventQueue *queue, const Span<uint8_t>  &ndef_buffer);
00055 
00056     /**
00057      * The NFCEEPROM delegate. Users of the NFCEEPROM class need to implement this delegate's methods to receive events.
00058      */
00059     struct Delegate : NFCTarget::Delegate {
00060         /**
00061          * The NDEF message erasing request completed.
00062          *
00063          * @param[in] result NFC_OK or an error code on failure
00064          */
00065         virtual void on_ndef_message_erased(nfc_err_t result) {}
00066 
00067         /**
00068          * The NDEF message writing request completed.
00069          *
00070          * @param[in] result NFC_OK or an error code on failure
00071          */
00072         virtual void on_ndef_message_written(nfc_err_t result) {}
00073 
00074         /**
00075          * The NDEF message reading request completed.
00076          *
00077          * @param[in] result NFC_OK or an error code on failure
00078          */
00079         virtual void on_ndef_message_read(nfc_err_t result) {}
00080 
00081     protected:
00082         ~Delegate() {}
00083     };
00084 
00085     /**
00086      * Initialize the NFC EEPROM
00087      *
00088      * This method must be called before any other method call.
00089      *
00090      * @return NFC_OK, or an error.
00091      */
00092     nfc_err_t initialize();
00093 
00094     /**
00095      * Set the delegate that will receive events generated by this EEPROM.
00096      *
00097      * @param[in] delegate the delegate instance to use
00098      */
00099     void set_delegate(Delegate *delegate);
00100 
00101     // Implementation of NFCTarget
00102     virtual void write_ndef_message();
00103     virtual void read_ndef_message();
00104     virtual void erase_ndef_message();
00105 
00106 private:
00107     // Implementation of NFCEEPROMDriver::Delegate
00108     virtual void on_session_started(bool success);
00109     virtual void on_session_ended(bool success);
00110     virtual void on_bytes_read(size_t count);
00111     virtual void on_bytes_written(size_t count);
00112     virtual void on_size_written(bool success);
00113     virtual void on_size_read(bool success, size_t size);
00114     virtual void on_bytes_erased(size_t count);
00115 
00116     void handle_error(nfc_err_t ret);
00117     void continue_write();
00118     void continue_read();
00119     void continue_erase();
00120 
00121     // NFCNDEFCapable implementation
00122     virtual NFCNDEFCapable::Delegate *ndef_capable_delegate();
00123 
00124     enum nfc_eeprom_operation_t {
00125         nfc_eeprom_idle,
00126 
00127         nfc_eeprom_write_start_session,
00128         nfc_eeprom_write_write_size,
00129         nfc_eeprom_write_write_bytes,
00130         nfc_eeprom_write_end_session,
00131 
00132         nfc_eeprom_read_start_session,
00133         nfc_eeprom_read_read_size,
00134         nfc_eeprom_read_read_bytes,
00135         nfc_eeprom_read_end_session,
00136 
00137         nfc_eeprom_erase_start_session,
00138         nfc_eeprom_erase_write_max_size,
00139         nfc_eeprom_erase_erase_bytes,
00140         nfc_eeprom_erase_write_0_size,
00141         nfc_eeprom_erase_end_session
00142     };
00143 
00144     Delegate *_delegate;
00145     NFCEEPROMDriver *_driver;
00146     events::EventQueue *_event_queue;
00147     bool _initialized;
00148 
00149     nfc_eeprom_operation_t _current_op;
00150     ac_buffer_t _ndef_buffer_reader;
00151     size_t _ndef_buffer_read_sz;
00152     uint32_t _eeprom_address;
00153     nfc_err_t _operation_result;
00154 };
00155 /** @}*/
00156 } // namespace nfc
00157 } // namespace mbed
00158 
00159 #endif