kushagra brahmbhatt / IoT_Security

IoT Home Alarm System

Dependents:   IoTBurglar_and_Fire_AlarmSystem

SPISlave.h@0:2f388b030837, 2016-04-29 (annotated)

Committer:
kbrahmbhatt6
Date:
Fri Apr 29 06:59:59 2016 +0000
Revision:
0:2f388b030837
1

Who changed what in which revision?

UserRevisionLine numberNew contents of line
kbrahmbhatt6 0:2f388b030837 1 /* mbed Microcontroller Library
kbrahmbhatt6 0:2f388b030837 2 * Copyright (c) 2006-2013 ARM Limited
kbrahmbhatt6 0:2f388b030837 3 *
kbrahmbhatt6 0:2f388b030837 4 * Licensed under the Apache License, Version 2.0 (the "License");
kbrahmbhatt6 0:2f388b030837 5 * you may not use this file except in compliance with the License.
kbrahmbhatt6 0:2f388b030837 6 * You may obtain a copy of the License at
kbrahmbhatt6 0:2f388b030837 7 *
kbrahmbhatt6 0:2f388b030837 8 * http://www.apache.org/licenses/LICENSE-2.0
kbrahmbhatt6 0:2f388b030837 9 *
kbrahmbhatt6 0:2f388b030837 10 * Unless required by applicable law or agreed to in writing, software
kbrahmbhatt6 0:2f388b030837 11 * distributed under the License is distributed on an "AS IS" BASIS,
kbrahmbhatt6 0:2f388b030837 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
kbrahmbhatt6 0:2f388b030837 13 * See the License for the specific language governing permissions and
kbrahmbhatt6 0:2f388b030837 14 * limitations under the License.
kbrahmbhatt6 0:2f388b030837 15 */
kbrahmbhatt6 0:2f388b030837 16 #ifndef MBED_SPISLAVE_H
kbrahmbhatt6 0:2f388b030837 17 #define MBED_SPISLAVE_H
kbrahmbhatt6 0:2f388b030837 18
kbrahmbhatt6 0:2f388b030837 19 #include "platform.h"
kbrahmbhatt6 0:2f388b030837 20
kbrahmbhatt6 0:2f388b030837 21 #if DEVICE_SPISLAVE
kbrahmbhatt6 0:2f388b030837 22
kbrahmbhatt6 0:2f388b030837 23 #include "spi_api.h"
kbrahmbhatt6 0:2f388b030837 24
kbrahmbhatt6 0:2f388b030837 25 namespace mbed {
kbrahmbhatt6 0:2f388b030837 26
kbrahmbhatt6 0:2f388b030837 27 /** A SPI slave, used for communicating with a SPI Master device
kbrahmbhatt6 0:2f388b030837 28 *
kbrahmbhatt6 0:2f388b030837 29 * The default format is set to 8-bits, mode 0, and a clock frequency of 1MHz
kbrahmbhatt6 0:2f388b030837 30 *
kbrahmbhatt6 0:2f388b030837 31 * Example:
kbrahmbhatt6 0:2f388b030837 32 * @code
kbrahmbhatt6 0:2f388b030837 33 * // Reply to a SPI master as slave
kbrahmbhatt6 0:2f388b030837 34 *
kbrahmbhatt6 0:2f388b030837 35 * #include "mbed.h"
kbrahmbhatt6 0:2f388b030837 36 *
kbrahmbhatt6 0:2f388b030837 37 * SPISlave device(p5, p6, p7, p8); // mosi, miso, sclk, ssel
kbrahmbhatt6 0:2f388b030837 38 *
kbrahmbhatt6 0:2f388b030837 39 * int main() {
kbrahmbhatt6 0:2f388b030837 40 * device.reply(0x00); // Prime SPI with first reply
kbrahmbhatt6 0:2f388b030837 41 * while(1) {
kbrahmbhatt6 0:2f388b030837 42 * if(device.receive()) {
kbrahmbhatt6 0:2f388b030837 43 * int v = device.read(); // Read byte from master
kbrahmbhatt6 0:2f388b030837 44 * v = (v + 1) % 0x100; // Add one to it, modulo 256
kbrahmbhatt6 0:2f388b030837 45 * device.reply(v); // Make this the next reply
kbrahmbhatt6 0:2f388b030837 46 * }
kbrahmbhatt6 0:2f388b030837 47 * }
kbrahmbhatt6 0:2f388b030837 48 * }
kbrahmbhatt6 0:2f388b030837 49 * @endcode
kbrahmbhatt6 0:2f388b030837 50 */
kbrahmbhatt6 0:2f388b030837 51 class SPISlave {
kbrahmbhatt6 0:2f388b030837 52
kbrahmbhatt6 0:2f388b030837 53 public:
kbrahmbhatt6 0:2f388b030837 54
kbrahmbhatt6 0:2f388b030837 55 /** Create a SPI slave connected to the specified pins
kbrahmbhatt6 0:2f388b030837 56 *
kbrahmbhatt6 0:2f388b030837 57 * Pin Options:
kbrahmbhatt6 0:2f388b030837 58 * (5, 6, 7i, 8) or (11, 12, 13, 14)
kbrahmbhatt6 0:2f388b030837 59 *
kbrahmbhatt6 0:2f388b030837 60 * mosi or miso can be specfied as NC if not used
kbrahmbhatt6 0:2f388b030837 61 *
kbrahmbhatt6 0:2f388b030837 62 * @param mosi SPI Master Out, Slave In pin
kbrahmbhatt6 0:2f388b030837 63 * @param miso SPI Master In, Slave Out pin
kbrahmbhatt6 0:2f388b030837 64 * @param sclk SPI Clock pin
kbrahmbhatt6 0:2f388b030837 65 * @param ssel SPI chip select pin
kbrahmbhatt6 0:2f388b030837 66 * @param name (optional) A string to identify the object
kbrahmbhatt6 0:2f388b030837 67 */
kbrahmbhatt6 0:2f388b030837 68 SPISlave(PinName mosi, PinName miso, PinName sclk, PinName ssel);
kbrahmbhatt6 0:2f388b030837 69
kbrahmbhatt6 0:2f388b030837 70 /** Configure the data transmission format
kbrahmbhatt6 0:2f388b030837 71 *
kbrahmbhatt6 0:2f388b030837 72 * @param bits Number of bits per SPI frame (4 - 16)
kbrahmbhatt6 0:2f388b030837 73 * @param mode Clock polarity and phase mode (0 - 3)
kbrahmbhatt6 0:2f388b030837 74 *
kbrahmbhatt6 0:2f388b030837 75 * @code
kbrahmbhatt6 0:2f388b030837 76 * mode | POL PHA
kbrahmbhatt6 0:2f388b030837 77 * -----+--------
kbrahmbhatt6 0:2f388b030837 78 * 0 | 0 0
kbrahmbhatt6 0:2f388b030837 79 * 1 | 0 1
kbrahmbhatt6 0:2f388b030837 80 * 2 | 1 0
kbrahmbhatt6 0:2f388b030837 81 * 3 | 1 1
kbrahmbhatt6 0:2f388b030837 82 * @endcode
kbrahmbhatt6 0:2f388b030837 83 */
kbrahmbhatt6 0:2f388b030837 84 void format(int bits, int mode = 0);
kbrahmbhatt6 0:2f388b030837 85
kbrahmbhatt6 0:2f388b030837 86 /** Set the spi bus clock frequency
kbrahmbhatt6 0:2f388b030837 87 *
kbrahmbhatt6 0:2f388b030837 88 * @param hz SCLK frequency in hz (default = 1MHz)
kbrahmbhatt6 0:2f388b030837 89 */
kbrahmbhatt6 0:2f388b030837 90 void frequency(int hz = 1000000);
kbrahmbhatt6 0:2f388b030837 91
kbrahmbhatt6 0:2f388b030837 92 /** Polls the SPI to see if data has been received
kbrahmbhatt6 0:2f388b030837 93 *
kbrahmbhatt6 0:2f388b030837 94 * @returns
kbrahmbhatt6 0:2f388b030837 95 * 0 if no data,
kbrahmbhatt6 0:2f388b030837 96 * 1 otherwise
kbrahmbhatt6 0:2f388b030837 97 */
kbrahmbhatt6 0:2f388b030837 98 int receive(void);
kbrahmbhatt6 0:2f388b030837 99
kbrahmbhatt6 0:2f388b030837 100 /** Retrieve data from receive buffer as slave
kbrahmbhatt6 0:2f388b030837 101 *
kbrahmbhatt6 0:2f388b030837 102 * @returns
kbrahmbhatt6 0:2f388b030837 103 * the data in the receive buffer
kbrahmbhatt6 0:2f388b030837 104 */
kbrahmbhatt6 0:2f388b030837 105 int read(void);
kbrahmbhatt6 0:2f388b030837 106
kbrahmbhatt6 0:2f388b030837 107 /** Fill the transmission buffer with the value to be written out
kbrahmbhatt6 0:2f388b030837 108 * as slave on the next received message from the master.
kbrahmbhatt6 0:2f388b030837 109 *
kbrahmbhatt6 0:2f388b030837 110 * @param value the data to be transmitted next
kbrahmbhatt6 0:2f388b030837 111 */
kbrahmbhatt6 0:2f388b030837 112 void reply(int value);
kbrahmbhatt6 0:2f388b030837 113
kbrahmbhatt6 0:2f388b030837 114 protected:
kbrahmbhatt6 0:2f388b030837 115 spi_t _spi;
kbrahmbhatt6 0:2f388b030837 116
kbrahmbhatt6 0:2f388b030837 117 int _bits;
kbrahmbhatt6 0:2f388b030837 118 int _mode;
kbrahmbhatt6 0:2f388b030837 119 int _hz;
kbrahmbhatt6 0:2f388b030837 120 };
kbrahmbhatt6 0:2f388b030837 121
kbrahmbhatt6 0:2f388b030837 122 } // namespace mbed
kbrahmbhatt6 0:2f388b030837 123
kbrahmbhatt6 0:2f388b030837 124 #endif
kbrahmbhatt6 0:2f388b030837 125
kbrahmbhatt6 0:2f388b030837 126 #endif