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  * SPI device(p5, p6, p7); // mosi, miso, sclk
00049  *
00050  * int main() {
00051  *     int response = device.write(0xFF);
00052  * }
00053  * @endcode
00054  */
00055 class SPI {
00056 
00057 public:
00058 
00059     /** Create a SPI master connected to the specified pins
00060      *
00061      * Pin Options:
00062      *  (5, 6, 7) or (11, 12, 13)
00063      *
00064      *  mosi or miso can be specfied as NC if not used
00065      *
00066      *  @param mosi SPI Master Out, Slave In pin
00067      *  @param miso SPI Master In, Slave Out pin
00068      *  @param sclk SPI Clock pin
00069      */
00070     SPI(PinName mosi, PinName miso, PinName sclk, PinName _unused=NC);
00071 
00072     /** Configure the data transmission format
00073      *
00074      *  @param bits Number of bits per SPI frame (4 - 16)
00075      *  @param mode Clock polarity and phase mode (0 - 3)
00076      *
00077      * @code
00078      * mode | POL PHA
00079      * -----+--------
00080      *   0  |  0   0
00081      *   1  |  0   1
00082      *   2  |  1   0
00083      *   3  |  1   1
00084      * @endcode
00085      */
00086     void format(int bits, int mode = 0);
00087 
00088     /** Set the spi bus clock frequency
00089      *
00090      *  @param hz SCLK frequency in hz (default = 1MHz)
00091      */
00092     void frequency(int hz = 1000000);
00093 
00094     /** Write to the SPI Slave and return the response
00095      *
00096      *  @param value Data to be sent to the SPI slave
00097      *
00098      *  @returns
00099      *    Response from the SPI slave
00100     */
00101     virtual int write(int value);
00102 
00103 #if DEVICE_SPI_ASYNCH
00104 
00105     /** Start non-blocking SPI transfer using 8bit buffers.
00106      *
00107      * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
00108      *                  the default SPI value is sent
00109      * @param tx_length The length of TX buffer
00110      * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
00111      *                  received data are ignored
00112      * @param rx_length The length of RX buffer
00113      * @param callback  The event callback function
00114      * @param event     The logical OR of events to modify
00115      * @return Zero if the transfer has started, or -1 if SPI peripheral is busy
00116      */
00117     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) {
00118         return transfer(tx_buffer, tx_length, rx_buffer, rx_length, 8, callback, event);
00119     }
00120 
00121     /** Start non-blocking SPI transfer using 16bit buffers.
00122      *
00123      * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
00124      *                  the default SPI value is sent
00125      * @param tx_length The length of TX buffer
00126      * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
00127      *                  received data are ignored
00128      * @param rx_length The length of RX buffer
00129      * @param callback  The event callback function
00130      * @param event     The logical OR of events to modify
00131      * @return Zero if the transfer has started, or -1 if SPI peripheral is busy
00132      */
00133     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) {
00134         return transfer(tx_buffer, tx_length, rx_buffer, rx_length, 16, callback, event);
00135     }
00136 
00137     /** Start non-blocking SPI transfer using 32bit buffers.
00138      *
00139      * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
00140      *                  the default SPI value is sent
00141      * @param tx_length The length of TX buffer
00142      * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
00143      *                  received data are ignored
00144      * @param rx_length The length of RX buffer
00145      * @param callback  The event callback function
00146      * @param event     The logical OR of events to modify
00147      * @return Zero if the transfer has started, or -1 if SPI peripheral is busy
00148      */
00149     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)  {
00150         return transfer((void *)tx_buffer, tx_length, (void *)rx_buffer, rx_length, 32, callback, event);
00151     }
00152 
00153     /** Abort the on-going SPI transfer, and continue with transfer's in the queue if any.
00154      */
00155     void abort_transfer();
00156 
00157     /** Clear the transaction buffer
00158      */
00159     void clear_transfer_buffer();
00160 
00161     /** Clear the transaction buffer and abort on-going transfer.
00162      */
00163     void abort_all_transfers();
00164 
00165     /** Configure DMA usage suggestion for non-blocking transfers
00166      *
00167      *  @param usage The usage DMA hint for peripheral
00168      *  @return Zero if the usage was set, -1 if a transaction is on-going
00169     */
00170     int set_dma_usage(DMAUsage usage);
00171 
00172 protected:
00173     /** SPI IRQ handler
00174      *
00175     */
00176     void irq_handler_asynch(void);
00177 
00178     /** Common transfer method
00179      *
00180      * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
00181      *                  the default SPI value is sent
00182      * @param tx_length The length of TX buffer
00183      * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
00184      *                  received data are ignored
00185      * @param rx_length The length of RX buffer
00186      * @param bit_width The buffers element width
00187      * @param callback  The event callback function
00188      * @param event     The logical OR of events to modify
00189      * @return Zero if the transfer has started or was added to the queue, or -1 if SPI peripheral is busy/buffer is full
00190     */
00191     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);
00192 
00193     /**
00194      *
00195      * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
00196      *                  the default SPI value is sent
00197      * @param tx_length The length of TX buffer
00198      * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
00199      *                  received data are ignored
00200      * @param rx_length The length of RX buffer
00201      * @param bit_width The buffers element width
00202      * @param callback  The event callback function
00203      * @param event     The logical OR of events to modify
00204      * @return Zero if a transfer was added to the queue, or -1 if the queue is full
00205     */
00206     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);
00207 
00208     /** Configures a callback, spi peripheral and initiate a new transfer
00209      *
00210      * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
00211      *                  the default SPI value is sent
00212      * @param tx_length The length of TX buffer
00213      * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
00214      *                  received data are ignored
00215      * @param rx_length The length of RX buffer
00216      * @param bit_width The buffers element width
00217      * @param callback  The event callback function
00218      * @param event     The logical OR of events to modify
00219     */
00220     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);
00221 
00222 #if TRANSACTION_QUEUE_SIZE_SPI
00223 
00224     /** Start a new transaction
00225      *
00226      *  @param data Transaction data
00227     */
00228     void start_transaction(transaction_t *data);
00229 
00230     /** Dequeue a transaction
00231      *
00232     */
00233     void dequeue_transaction();
00234     static CircularBuffer<Transaction<SPI>, TRANSACTION_QUEUE_SIZE_SPI> _transaction_buffer;
00235 #endif
00236 
00237 #endif
00238 
00239 public:
00240     virtual ~SPI() {
00241     }
00242 
00243 protected:
00244     spi_t _spi;
00245 
00246 #if DEVICE_SPI_ASYNCH
00247     CThunk<SPI> _irq;
00248     event_callback_t _callback;
00249     DMAUsage _usage;
00250 #endif
00251 
00252     void aquire(void);
00253     static SPI *_owner;
00254     int _bits;
00255     int _mode;
00256     int _hz;
00257 };
00258 
00259 } // namespace mbed
00260 
00261 #endif
00262 
00263 #endif