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SPISlave.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_SPISLAVE_H 00017 #define MBED_SPISLAVE_H 00018 00019 #include "platform.h" 00020 00021 #if DEVICE_SPISLAVE 00022 00023 #include "spi_api.h" 00024 00025 namespace mbed { 00026 00027 /** A SPI slave, used for communicating with a SPI Master device 00028 * 00029 * The default format is set to 8-bits, mode 0, and a clock frequency of 1MHz 00030 * 00031 * Example: 00032 * @code 00033 * // Reply to a SPI master as slave 00034 * 00035 * #include "mbed.h" 00036 * 00037 * SPISlave device(p5, p6, p7, p8); // mosi, miso, sclk, ssel 00038 * 00039 * int main() { 00040 * device.reply(0x00); // Prime SPI with first reply 00041 * while(1) { 00042 * if(device.receive()) { 00043 * int v = device.read(); // Read byte from master 00044 * v = (v + 1) % 0x100; // Add one to it, modulo 256 00045 * device.reply(v); // Make this the next reply 00046 * } 00047 * } 00048 * } 00049 * @endcode 00050 */ 00051 class SPISlave { 00052 00053 public: 00054 00055 /** Create a SPI slave connected to the specified pins 00056 * 00057 * mosi or miso can be specfied as NC if not used 00058 * 00059 * @param mosi SPI Master Out, Slave In pin 00060 * @param miso SPI Master In, Slave Out pin 00061 * @param sclk SPI Clock pin 00062 * @param ssel SPI chip select pin 00063 */ 00064 SPISlave(PinName mosi, PinName miso, PinName sclk, PinName ssel); 00065 00066 /** Configure the data transmission format 00067 * 00068 * @param bits Number of bits per SPI frame (4 - 16) 00069 * @param mode Clock polarity and phase mode (0 - 3) 00070 * 00071 * @code 00072 * mode | POL PHA 00073 * -----+-------- 00074 * 0 | 0 0 00075 * 1 | 0 1 00076 * 2 | 1 0 00077 * 3 | 1 1 00078 * @endcode 00079 */ 00080 void format(int bits, int mode = 0); 00081 00082 /** Set the spi bus clock frequency 00083 * 00084 * @param hz SCLK frequency in hz (default = 1MHz) 00085 */ 00086 void frequency(int hz = 1000000); 00087 00088 /** Polls the SPI to see if data has been received 00089 * 00090 * @returns 00091 * 0 if no data, 00092 * 1 otherwise 00093 */ 00094 int receive(void); 00095 00096 /** Retrieve data from receive buffer as slave 00097 * 00098 * @returns 00099 * the data in the receive buffer 00100 */ 00101 int read(void); 00102 00103 /** Fill the transmission buffer with the value to be written out 00104 * as slave on the next received message from the master. 00105 * 00106 * @param value the data to be transmitted next 00107 */ 00108 void reply(int value); 00109 00110 protected: 00111 spi_t _spi; 00112 00113 int _bits; 00114 int _mode; 00115 int _hz; 00116 }; 00117 00118 } // namespace mbed 00119 00120 #endif 00121 00122 #endif
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