Luth Haroon / SD_modified

SD card interface

mbed-export/SPIHalfDuplex.h@0:22612ae617a0, 2012-10-08 (annotated)

Committer:
lharoon
Date:
Mon Oct 08 11:14:07 2012 +0000
Revision:
0:22612ae617a0
1st edition

Who changed what in which revision?

UserRevisionLine numberNew contents of line
lharoon 0:22612ae617a0 1 /* mbed Microcontroller Library - SPIHalfDuplex
lharoon 0:22612ae617a0 2 * Copyright (c) 2010-2011 ARM Limited. All rights reserved.
lharoon 0:22612ae617a0 3 */
lharoon 0:22612ae617a0 4
lharoon 0:22612ae617a0 5 #ifndef MBED_SPIHALFDUPLEX_H
lharoon 0:22612ae617a0 6 #define MBED_SPIHALFDUPLEX_H
lharoon 0:22612ae617a0 7
lharoon 0:22612ae617a0 8 #include "device.h"
lharoon 0:22612ae617a0 9
lharoon 0:22612ae617a0 10 #if DEVICE_SPI
lharoon 0:22612ae617a0 11
lharoon 0:22612ae617a0 12 #include "SPI.h"
lharoon 0:22612ae617a0 13
lharoon 0:22612ae617a0 14 namespace mbed {
lharoon 0:22612ae617a0 15
lharoon 0:22612ae617a0 16 /* Class: SPIHalfDuplex
lharoon 0:22612ae617a0 17 * A SPI half-duplex master, used for communicating with SPI slave devices
lharoon 0:22612ae617a0 18 * over a shared data line.
lharoon 0:22612ae617a0 19 *
lharoon 0:22612ae617a0 20 * The default format is set to 8-bits for both master and slave, and a
lharoon 0:22612ae617a0 21 * clock frequency of 1MHz
lharoon 0:22612ae617a0 22 *
lharoon 0:22612ae617a0 23 * Most SPI devies will also require Chip Select and Reset signals. These
lharoon 0:22612ae617a0 24 * can be controlled using <DigitalOut> pins.
lharoon 0:22612ae617a0 25 *
lharoon 0:22612ae617a0 26 * Although this is for a shared data line, both MISO and MOSI are defined,
lharoon 0:22612ae617a0 27 * and should be tied together externally to the mbed. This class handles
lharoon 0:22612ae617a0 28 * the tri-stating of the MOSI pin.
lharoon 0:22612ae617a0 29 *
lharoon 0:22612ae617a0 30 * Example:
lharoon 0:22612ae617a0 31 * > // Send a byte to a SPI half-duplex slave, and record the response
lharoon 0:22612ae617a0 32 * >
lharoon 0:22612ae617a0 33 * > #include "mbed.h"
lharoon 0:22612ae617a0 34 * >
lharoon 0:22612ae617a0 35 * > SPIHalfDuplex device(p5, p6, p7) // mosi, miso, sclk
lharoon 0:22612ae617a0 36 * >
lharoon 0:22612ae617a0 37 * > int main() {
lharoon 0:22612ae617a0 38 * > int respone = device.write(0xAA);
lharoon 0:22612ae617a0 39 * > }
lharoon 0:22612ae617a0 40 */
lharoon 0:22612ae617a0 41
lharoon 0:22612ae617a0 42 class SPIHalfDuplex : public SPI {
lharoon 0:22612ae617a0 43
lharoon 0:22612ae617a0 44 public:
lharoon 0:22612ae617a0 45
lharoon 0:22612ae617a0 46 /* Constructor: SPIHalfDuplex
lharoon 0:22612ae617a0 47 * Create a SPI half-duplex master connected to the specified pins
lharoon 0:22612ae617a0 48 *
lharoon 0:22612ae617a0 49 * Variables:
lharoon 0:22612ae617a0 50 * mosi - SPI Master Out, Slave In pin
lharoon 0:22612ae617a0 51 * miso - SPI Master In, Slave Out pin
lharoon 0:22612ae617a0 52 * sclk - SPI Clock pin
lharoon 0:22612ae617a0 53 * name - (optional) A string to identify the object
lharoon 0:22612ae617a0 54 *
lharoon 0:22612ae617a0 55 * Pin Options:
lharoon 0:22612ae617a0 56 * (5, 6, 7) or (11, 12, 13)
lharoon 0:22612ae617a0 57 *
lharoon 0:22612ae617a0 58 * mosi or miso can be specfied as NC if not used
lharoon 0:22612ae617a0 59 */
lharoon 0:22612ae617a0 60 SPIHalfDuplex(PinName mosi, PinName miso, PinName sclk,
lharoon 0:22612ae617a0 61 const char *name = NULL);
lharoon 0:22612ae617a0 62
lharoon 0:22612ae617a0 63 #if 0 // Inherited from SPI - documentation only
lharoon 0:22612ae617a0 64 /* Function: format
lharoon 0:22612ae617a0 65 * Configure the data transmission format
lharoon 0:22612ae617a0 66 *
lharoon 0:22612ae617a0 67 * Variables:
lharoon 0:22612ae617a0 68 * bits - Number of bits per SPI frame (4 - 16)
lharoon 0:22612ae617a0 69 * mode - Clock polarity and phase mode (0 - 3)
lharoon 0:22612ae617a0 70 *
lharoon 0:22612ae617a0 71 * > mode | POL PHA
lharoon 0:22612ae617a0 72 * > -----+--------
lharoon 0:22612ae617a0 73 * > 0 | 0 0
lharoon 0:22612ae617a0 74 * > 1 | 0 1
lharoon 0:22612ae617a0 75 * > 2 | 1 0
lharoon 0:22612ae617a0 76 * > 3 | 1 1
lharoon 0:22612ae617a0 77 */
lharoon 0:22612ae617a0 78 void format(int bits, int mode = 0);
lharoon 0:22612ae617a0 79
lharoon 0:22612ae617a0 80 /* Function: frequency
lharoon 0:22612ae617a0 81 * Set the spi bus clock frequency
lharoon 0:22612ae617a0 82 *
lharoon 0:22612ae617a0 83 * Variables:
lharoon 0:22612ae617a0 84 * hz - SCLK frequency in hz (default = 1MHz)
lharoon 0:22612ae617a0 85 */
lharoon 0:22612ae617a0 86 void frequency(int hz = 1000000);
lharoon 0:22612ae617a0 87 #endif
lharoon 0:22612ae617a0 88
lharoon 0:22612ae617a0 89 /* Function: write
lharoon 0:22612ae617a0 90 * Write to the SPI Slave and return the response
lharoon 0:22612ae617a0 91 *
lharoon 0:22612ae617a0 92 * Variables:
lharoon 0:22612ae617a0 93 * value - Data to be sent to the SPI slave
lharoon 0:22612ae617a0 94 * returns - Response from the SPI slave
lharoon 0:22612ae617a0 95 */
lharoon 0:22612ae617a0 96 virtual int write(int value);
lharoon 0:22612ae617a0 97
lharoon 0:22612ae617a0 98 /* Function: slave_format
lharoon 0:22612ae617a0 99 * Set the number of databits expected from the slave, from 4-16
lharoon 0:22612ae617a0 100 *
lharoon 0:22612ae617a0 101 * Variables:
lharoon 0:22612ae617a0 102 * sbits - Number of expected bits in the slave response
lharoon 0:22612ae617a0 103 */
lharoon 0:22612ae617a0 104 void slave_format(int sbits);
lharoon 0:22612ae617a0 105
lharoon 0:22612ae617a0 106 protected:
lharoon 0:22612ae617a0 107 PinName _mosi;
lharoon 0:22612ae617a0 108 PinName _miso;
lharoon 0:22612ae617a0 109 int _sbits;
lharoon 0:22612ae617a0 110
lharoon 0:22612ae617a0 111 }; // End of class
lharoon 0:22612ae617a0 112
lharoon 0:22612ae617a0 113 } // End of namespace mbed
lharoon 0:22612ae617a0 114
lharoon 0:22612ae617a0 115 #endif
lharoon 0:22612ae617a0 116
lharoon 0:22612ae617a0 117 #endif