SPI.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2015 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 #ifndef MBED_SPI_H
00017 #define MBED_SPI_H
00018 
00019 #include "platform.h"
00020 
00021 // for 100F6 not implemented (N.S.)
00022 #undef DEVICE_SPI_ASYNCH
00023 
00024 
00025 #if DEVICE_SPI
00026 
00027 #include "spi_api.h"
00028 
00029 #if DEVICE_SPI_ASYNCH
00030 #include "CThunk.h"
00031 #include "dma_api.h"
00032 #include "CircularBuffer.h"
00033 #include "FunctionPointer.h"
00034 #include "Transaction.h"
00035 #endif
00036 
00037 namespace mbed {
00038 
00039 /** A SPI Master, used for communicating with SPI slave devices
00040  *
00041  * The default format is set to 8-bits, mode 0, and a clock frequency of 1MHz
00042  *
00043  * Most SPI devices will also require Chip Select and Reset signals. These
00044  * can be controlled using <DigitalOut> pins
00045  *
00046  * Example:
00047  * @code
00048  * // Send a byte to a SPI slave, and record the response
00049  *
00050  * #include "mbed.h"
00051  *
00052  * // hardware ssel (where applicable)
00053  * //SPI device(p5, p6, p7, p8); // mosi, miso, sclk, ssel
00054  *
00055  * // software ssel
00056  * SPI device(p5, p6, p7); // mosi, miso, sclk
00057  * DigitalOut cs(p8); // ssel
00058  *
00059  * int main() {
00060  *     // hardware ssel (where applicable)
00061  *     //int response = device.write(0xFF);
00062  *
00063  *     // software ssel
00064  *     cs = 0;
00065  *     int response = device.write(0xFF);
00066  *     cs = 1;
00067  * }
00068  * @endcode
00069  */
00070 class SPI {
00071 
00072 public:
00073 
00074     /** Create a SPI master connected to the specified pins
00075      *
00076      *  mosi or miso can be specfied as NC if not used
00077      *
00078      *  @param mosi SPI Master Out, Slave In pin
00079      *  @param miso SPI Master In, Slave Out pin
00080      *  @param sclk SPI Clock pin
00081      *  @param ssel SPI chip select pin
00082      */
00083     SPI(PinName mosi, PinName miso, PinName sclk, PinName ssel=NC);
00084 
00085     /** Configure the data transmission format
00086      *
00087      *  @param bits Number of bits per SPI frame (4 - 16)
00088      *  @param mode Clock polarity and phase mode (0 - 3)
00089      *
00090      * @code
00091      * mode | POL PHA
00092      * -----+--------
00093      *   0  |  0   0
00094      *   1  |  0   1
00095      *   2  |  1   0
00096      *   3  |  1   1
00097      * @endcode
00098      */
00099     void format(int bits, int mode = 0);
00100 
00101     /** Set the spi bus clock frequency
00102      *
00103      *  @param hz SCLK frequency in hz (default = 1MHz)
00104      */
00105     void frequency(int hz = 1000000);
00106 
00107     /** Write to the SPI Slave and return the response
00108      *
00109      *  @param value Data to be sent to the SPI slave
00110      *
00111      *  @returns
00112      *    Response from the SPI slave
00113     */
00114     virtual int write(int value);
00115 
00116 #if DEVICE_SPI_ASYNCH
00117 
00118     /** Start non-blocking SPI transfer using 8bit buffers.
00119      *
00120      * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
00121      *                  the default SPI value is sent
00122      * @param tx_length The length of TX buffer in bytes
00123      * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
00124      *                  received data are ignored
00125      * @param rx_length The length of RX buffer in bytes
00126      * @param callback  The event callback function
00127      * @param event     The logical OR of events to modify. Look at spi hal header file for SPI events.
00128      * @return Zero if the transfer has started, or -1 if SPI peripheral is busy
00129      */
00130     template<typename Type>
00131     int transfer(const Type *tx_buffer, int tx_length, Type *rx_buffer, int rx_length, const event_callback_t & callback, int event = SPI_EVENT_COMPLETE) {
00132         if (spi_active(&_spi)) {
00133             return queue_transfer (tx_buffer, tx_length, rx_buffer, rx_length, sizeof(Type)*8, callback, event);
00134         }
00135         start_transfer(tx_buffer, tx_length, rx_buffer, rx_length, sizeof(Type)*8, callback, event);
00136         return 0;
00137     }
00138 
00139     /** Abort the on-going SPI transfer, and continue with transfer's in the queue if any.
00140      */
00141     void abort_transfer();
00142 
00143     /** Clear the transaction buffer
00144      */
00145     void clear_transfer_buffer();
00146 
00147     /** Clear the transaction buffer and abort on-going transfer.
00148      */
00149     void abort_all_transfers();
00150 
00151     /** Configure DMA usage suggestion for non-blocking transfers
00152      *
00153      *  @param usage The usage DMA hint for peripheral
00154      *  @return Zero if the usage was set, -1 if a transaction is on-going
00155     */
00156     int set_dma_usage(DMAUsage usage);
00157 
00158 protected:
00159     /** SPI IRQ handler
00160      *
00161     */
00162     void irq_handler_asynch(void);
00163 
00164     /** Common transfer method
00165      *
00166      * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
00167      *                  the default SPI value is sent
00168      * @param tx_length The length of TX buffer in bytes
00169      * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
00170      *                  received data are ignored
00171      * @param rx_length The length of RX buffer in bytes
00172      * @param bit_width The buffers element width
00173      * @param callback  The event callback function
00174      * @param event     The logical OR of events to modify
00175      * @return Zero if the transfer has started or was added to the queue, or -1 if SPI peripheral is busy/buffer is full
00176     */
00177     int transfer(const void *tx_buffer, int tx_length, void *rx_buffer, int rx_length, unsigned char bit_width, const event_callback_t & callback, int event);
00178 
00179     /**
00180      *
00181      * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
00182      *                  the default SPI value is sent
00183      * @param tx_length The length of TX buffer in bytes
00184      * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
00185      *                  received data are ignored
00186      * @param rx_length The length of RX buffer in bytes
00187      * @param bit_width The buffers element width
00188      * @param callback  The event callback function
00189      * @param event     The logical OR of events to modify
00190      * @return Zero if a transfer was added to the queue, or -1 if the queue is full
00191     */
00192     int queue_transfer (const void *tx_buffer, int tx_length, void *rx_buffer, int rx_length, unsigned char bit_width, const event_callback_t & callback, int event);
00193 
00194     /** Configures a callback, spi peripheral and initiate a new transfer
00195      *
00196      * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
00197      *                  the default SPI value is sent
00198      * @param tx_length The length of TX buffer in bytes
00199      * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
00200      *                  received data are ignored
00201      * @param rx_length The length of RX buffer in bytes
00202      * @param bit_width The buffers element width
00203      * @param callback  The event callback function
00204      * @param event     The logical OR of events to modify
00205     */
00206     void start_transfer(const void *tx_buffer, int tx_length, void *rx_buffer, int rx_length, unsigned char bit_width, const event_callback_t & callback, int event);
00207 
00208 #if TRANSACTION_QUEUE_SIZE_SPI
00209 
00210     /** Start a new transaction
00211      *
00212      *  @param data Transaction data
00213     */
00214     void start_transaction(transaction_t *data);
00215 
00216     /** Dequeue a transaction
00217      *
00218     */
00219     void dequeue_transaction();
00220     static CircularBuffer<Transaction<SPI>, TRANSACTION_QUEUE_SIZE_SPI> _transaction_buffer;
00221 #endif
00222 
00223 #endif
00224 
00225 public:
00226     virtual ~SPI() {
00227     }
00228 
00229 protected:
00230     spi_t _spi;
00231 
00232 #if DEVICE_SPI_ASYNCH
00233     CThunk<SPI> _irq;
00234     event_callback_t _callback;
00235     DMAUsage _usage;
00236 #endif
00237 
00238     void aquire(void);
00239     static SPI *_owner;
00240     int _bits;
00241     int _mode;
00242     int _hz;
00243 };
00244 
00245 } // namespace mbed
00246 
00247 #endif
00248 
00249 #endif