SPI.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2013 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 namespace mbed {
00026 
00027 /** A SPI Master, used for communicating with SPI slave devices
00028  *
00029  * The default format is set to 8-bits, mode 0, and a clock frequency of 1MHz
00030  *
00031  * Most SPI devices will also require Chip Select and Reset signals. These
00032  * can be controlled using <DigitalOut> pins
00033  *
00034  * Example:
00035  * @code
00036  * // Send a byte to a SPI slave, and record the response
00037  *
00038  * #include "mbed.h"
00039  *
00040  * SPI device(p5, p6, p7); // mosi, miso, sclk
00041  *
00042  * int main() {
00043  *     int response = device.write(0xFF);
00044  * }
00045  * @endcode
00046  */
00047 class SPI {
00048 
00049 public:
00050 
00051     /** Create a SPI master connected to the specified pins
00052      *
00053      * Pin Options:
00054      *  (5, 6, 7) or (11, 12, 13)
00055      *
00056      *  mosi or miso can be specfied as NC if not used
00057      *
00058      *  @param mosi SPI Master Out, Slave In pin
00059      *  @param miso SPI Master In, Slave Out pin
00060      *  @param sclk SPI Clock pin
00061      */
00062     SPI(PinName mosi, PinName miso, PinName sclk, PinName _unused=NC);
00063 
00064     /** Configure the data transmission format
00065      *
00066      *  @param bits Number of bits per SPI frame (4 - 16)
00067      *  @param mode Clock polarity and phase mode (0 - 3)
00068      *
00069      * @code
00070      * mode | POL PHA
00071      * -----+--------
00072      *   0  |  0   0
00073      *   1  |  0   1
00074      *   2  |  1   0
00075      *   3  |  1   1
00076      * @endcode
00077      */
00078     void format(int bits, int mode = 0);
00079 
00080     /** Set the spi bus clock frequency
00081      *
00082      *  @param hz SCLK frequency in hz (default = 1MHz)
00083      */
00084     void frequency(int hz = 1000000);
00085 
00086     /** Write to the SPI Slave and return the response
00087      *
00088      *  @param value Data to be sent to the SPI slave
00089      *
00090      *  @returns
00091      *    Response from the SPI slave
00092     */
00093     virtual int write(int value);
00094 
00095 protected:
00096     spi_t _spi;
00097 
00098     void aquire(void);
00099     static SPI *_owner;
00100     int _bits;
00101     int _mode;
00102     int _hz;
00103 };
00104 
00105 } // namespace mbed
00106 
00107 #endif
00108 
00109 #endif