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 #if DEVICE_SPI
00022 
00023 #include "spi_api.h"
00024 
00025 #if DEVICE_SPI_ASYNCH
00026 #include "CThunk.h"
00027 #include "dma_api.h"
00028 #include "CircularBuffer.h"
00029 #include "FunctionPointer.h"
00030 #include "Transaction.h"
00031 #endif
00032 
00033 namespace mbed {
00034 
00035 /** A SPI Master, used for communicating with SPI slave devices
00036  *
00037  * The default format is set to 8-bits, mode 0, and a clock frequency of 1MHz
00038  *
00039  * Most SPI devices will also require Chip Select and Reset signals. These
00040  * can be controlled using <DigitalOut> pins
00041  *
00042  * Example:
00043  * @code
00044  * // Send a byte to a SPI slave, and record the response
00045  *
00046  * #include "mbed.h"
00047  *
00048  * // hardware ssel (where applicable)
00049  * //SPI device(p5, p6, p7, p8); // mosi, miso, sclk, ssel
00050  *
00051  * // software ssel
00052  * SPI device(p5, p6, p7); // mosi, miso, sclk
00053  * DigitalOut cs(p8); // ssel
00054  *
00055  * int main() {
00056  *     // hardware ssel (where applicable)
00057  *     //int response = device.write(0xFF);
00058  *
00059  *     // software ssel
00060  *     cs = 0;
00061  *     int response = device.write(0xFF);
00062  *     cs = 1;
00063  * }
00064  * @endcode
00065  */
00066 class SPI {
00067 
00068 public:
00069 
00070     /** Create a SPI master connected to the specified pins
00071      *
00072      *  mosi or miso can be specfied as NC if not used
00073      *
00074      *  @param mosi SPI Master Out, Slave In pin
00075      *  @param miso SPI Master In, Slave Out pin
00076      *  @param sclk SPI Clock pin
00077      *  @param ssel SPI chip select pin
00078      */
00079     SPI(PinName mosi, PinName miso, PinName sclk, PinName ssel=NC);
00080 
00081     /** Configure the data transmission format
00082      *
00083      *  @param bits Number of bits per SPI frame (4 - 16)
00084      *  @param mode Clock polarity and phase mode (0 - 3)
00085      *
00086      * @code
00087      * mode | POL PHA
00088      * -----+--------
00089      *   0  |  0   0
00090      *   1  |  0   1
00091      *   2  |  1   0
00092      *   3  |  1   1
00093      * @endcode
00094      */
00095     void format(int bits, int mode = 0);
00096 
00097     /** Set the spi bus clock frequency
00098      *
00099      *  @param hz SCLK frequency in hz (default = 1MHz)
00100      */
00101     void frequency(int hz = 1000000);
00102 
00103     /** Write to the SPI Slave and return the response
00104      *
00105      *  @param value Data to be sent to the SPI slave
00106      *
00107      *  @returns
00108      *    Response from the SPI slave
00109     */
00110     virtual int write(int value);
00111 
00112 #if DEVICE_SPI_ASYNCH
00113 
00114     /** Start non-blocking SPI transfer using 8bit buffers.
00115      *
00116      * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
00117      *                  the default SPI value is sent
00118      * @param tx_length The length of TX buffer
00119      * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
00120      *                  received data are ignored
00121      * @param rx_length The length of RX buffer
00122      * @param callback  The event callback function
00123      * @param event     The logical OR of events to modify
00124      * @return Zero if the transfer has started, or -1 if SPI peripheral is busy
00125      */
00126     virtual int transfer(uint8_t *tx_buffer, int tx_length, uint8_t *rx_buffer, int rx_length, const event_callback_t & callback, int event = SPI_EVENT_COMPLETE) {
00127         return transfer(tx_buffer, tx_length, rx_buffer, rx_length, 8, callback, event);
00128     }
00129 
00130     /** Start non-blocking SPI transfer using 16bit buffers.
00131      *
00132      * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
00133      *                  the default SPI value is sent
00134      * @param tx_length The length of TX buffer
00135      * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
00136      *                  received data are ignored
00137      * @param rx_length The length of RX buffer
00138      * @param callback  The event callback function
00139      * @param event     The logical OR of events to modify
00140      * @return Zero if the transfer has started, or -1 if SPI peripheral is busy
00141      */
00142     virtual int transfer(uint16_t *tx_buffer, int tx_length, uint16_t *rx_buffer, int rx_length, const event_callback_t & callback, int event = SPI_EVENT_COMPLETE) {
00143         return transfer(tx_buffer, tx_length, rx_buffer, rx_length, 16, callback, event);
00144     }
00145 
00146     /** Start non-blocking SPI transfer using 32bit buffers.
00147      *
00148      * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
00149      *                  the default SPI value is sent
00150      * @param tx_length The length of TX buffer
00151      * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
00152      *                  received data are ignored
00153      * @param rx_length The length of RX buffer
00154      * @param callback  The event callback function
00155      * @param event     The logical OR of events to modify
00156      * @return Zero if the transfer has started, or -1 if SPI peripheral is busy
00157      */
00158     virtual int transfer(uint32_t *tx_buffer, int tx_length, uint32_t *rx_buffer, int rx_length, const event_callback_t & callback, int event = SPI_EVENT_COMPLETE)  {
00159         return transfer((void *)tx_buffer, tx_length, (void *)rx_buffer, rx_length, 32, callback, event);
00160     }
00161 
00162     /** Abort the on-going SPI transfer, and continue with transfer's in the queue if any.
00163      */
00164     void abort_transfer();
00165 
00166     /** Clear the transaction buffer
00167      */
00168     void clear_transfer_buffer();
00169 
00170     /** Clear the transaction buffer and abort on-going transfer.
00171      */
00172     void abort_all_transfers();
00173 
00174     /** Configure DMA usage suggestion for non-blocking transfers
00175      *
00176      *  @param usage The usage DMA hint for peripheral
00177      *  @return Zero if the usage was set, -1 if a transaction is on-going
00178     */
00179     int set_dma_usage(DMAUsage usage);
00180 
00181 protected:
00182     /** SPI IRQ handler
00183      *
00184     */
00185     void irq_handler_asynch(void);
00186 
00187     /** Common transfer method
00188      *
00189      * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
00190      *                  the default SPI value is sent
00191      * @param tx_length The length of TX buffer
00192      * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
00193      *                  received data are ignored
00194      * @param rx_length The length of RX buffer
00195      * @param bit_width The buffers element width
00196      * @param callback  The event callback function
00197      * @param event     The logical OR of events to modify
00198      * @return Zero if the transfer has started or was added to the queue, or -1 if SPI peripheral is busy/buffer is full
00199     */
00200     int transfer(void *tx_buffer, int tx_length, void *rx_buffer, int rx_length, unsigned char bit_width, const event_callback_t & callback, int event);
00201 
00202     /**
00203      *
00204      * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
00205      *                  the default SPI value is sent
00206      * @param tx_length The length of TX buffer
00207      * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
00208      *                  received data are ignored
00209      * @param rx_length The length of RX buffer
00210      * @param bit_width The buffers element width
00211      * @param callback  The event callback function
00212      * @param event     The logical OR of events to modify
00213      * @return Zero if a transfer was added to the queue, or -1 if the queue is full
00214     */
00215     int queue_transfer (void *tx_buffer, int tx_length, void *rx_buffer, int rx_length, unsigned char bit_width, const event_callback_t & callback, int event);
00216 
00217     /** Configures a callback, spi peripheral and initiate a new transfer
00218      *
00219      * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
00220      *                  the default SPI value is sent
00221      * @param tx_length The length of TX buffer
00222      * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
00223      *                  received data are ignored
00224      * @param rx_length The length of RX buffer
00225      * @param bit_width The buffers element width
00226      * @param callback  The event callback function
00227      * @param event     The logical OR of events to modify
00228     */
00229     void start_transfer(void *tx_buffer, int tx_length, void *rx_buffer, int rx_length, unsigned char bit_width, const event_callback_t & callback, int event);
00230 
00231 #if TRANSACTION_QUEUE_SIZE_SPI
00232 
00233     /** Start a new transaction
00234      *
00235      *  @param data Transaction data
00236     */
00237     void start_transaction(transaction_t *data);
00238 
00239     /** Dequeue a transaction
00240      *
00241     */
00242     void dequeue_transaction();
00243     static CircularBuffer<Transaction<SPI>, TRANSACTION_QUEUE_SIZE_SPI> _transaction_buffer;
00244 #endif
00245 
00246 #endif
00247 
00248 public:
00249     virtual ~SPI() {
00250     }
00251 
00252 protected:
00253     spi_t _spi;
00254 
00255 #if DEVICE_SPI_ASYNCH
00256     CThunk<SPI> _irq;
00257     event_callback_t _callback;
00258     DMAUsage _usage;
00259 #endif
00260 
00261     void aquire(void);
00262     static SPI *_owner;
00263     int _bits;
00264     int _mode;
00265     int _hz;
00266 };
00267 
00268 } // namespace mbed
00269 
00270 #endif
00271 
00272 #endif