I2S.h

00001 /**
00002 * @author Giles Barton-Owen
00003 *
00004 * @section LICENSE
00005 *
00006 * Copyright (c) 2012 mbed
00007 *
00008 * Permission is hereby granted, free of charge, to any person obtaining a copy
00009 * of this software and associated documentation files (the "Software"), to deal
00010 * in the Software without restriction, including without limitation the rights
00011 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00012 * copies of the Software, and to permit persons to whom the Software is
00013 * furnished to do so, subject to the following conditions:
00014 *
00015 * The above copyright notice and this permission notice shall be included in
00016 * all copies or substantial portions of the Software.
00017 *
00018 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00019 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00020 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00021 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00022 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00023 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00024 * THE SOFTWARE.
00025 *
00026 * @section DESCRIPTION
00027 *    A I2S library for the LPC1768's built-in I2S peripheral
00028 *
00029 */
00030 
00031 #include "mbed.h"
00032 #include "math.h"
00033 #include "MK64F12.h"
00034 
00035 #ifndef I2S_H
00036 #define I2S_H
00037 
00038 #define I2S_TRANSMIT     0
00039 #define I2S_RECEIVE     1
00040 
00041 #define I2S_MASTER     0
00042 #define I2S_SLAVE     1
00043 
00044 #define I2S_STEREO     0
00045 #define I2S_MONO     1
00046 
00047 #define I2S_MUTED     1
00048 #define I2S_UNMUTED 0
00049 
00050 #define I2S_4WIRE     1
00051 #define I2S_3WIRE     0
00052 
00053 /** A class to play give access to the I2S library
00054  */
00055 
00056 class I2S
00057 {
00058 
00059 public:
00060 
00061     /** Create a I2S instance
00062      *
00063      * @param rxtx     Set the I2S instance to be transmit or recieve (I2S_TRANSMIT/I2S_RECEIVE)
00064      * @param SerialData    The serial data pin
00065      * @param WordSelect    The word select pin
00066      * @param BitClk    The clock pin
00067      */
00068     I2S(bool rxtx, PinName SerialData, PinName WordSelect, PinName BitClk);
00069 
00070     /** Create a I2S instance: Only with the serial data line set. Won't really do much.
00071      *
00072      * @param rxtx     Set the I2S instance to be transmit or recieve (I2S_TRANSMIT/I2S_RECEIVE)
00073      * @param SerialData    The serial data pin
00074      */
00075     // I2S(bool rxtx, PinName SerialData);
00076 
00077 
00078     /** Create a I2S instance: Only with serial data line and word select.
00079      *
00080      * @param rxtx     Set the I2S instance to be transmit or recieve (I2S_TRANSMIT/I2S_RECEIVE)
00081      * @param SerialData    The serial data pin
00082      * @param WordSelect    The word select pin
00083      */
00084     // I2S(bool rxtx, PinName SerialData, PinName WordSelect);
00085 
00086 
00087 
00088     /** Create a I2S instance: Only with serial data line. Four wire mode means this is functional
00089      *
00090      * @param rxtx     Set the I2S instance to be transmit or recieve (I2S_TRANSMIT/I2S_RECEIVE)
00091      * @param SerialData    The serial data pin
00092      * @param fourwiremode True means the peripheral is in 4-wire mode. It borroWordSelect WS and CLK from the other half
00093      */
00094     // I2S(bool rxtx, PinName SerialData, bool fourwiremode);
00095 
00096     /** Create a I2S instance: Only with serial data line and word select line. Four wire mode means this is functional
00097      *
00098      * @param rxtx     Set the I2S instance to be transmit or recieve (I2S_TRANSMIT/I2S_RECEIVE)
00099      * @param SerialData    The serial data pin
00100      * @param WordSelect    The word select pin
00101      * @param fourwiremode True means the peripheral is in 4-wire mode. It borroWordSelect WS and CLK from the other half
00102      */
00103     // I2S(bool rxtx, PinName SerialData, PinName WordSelect, bool fourwiremode);
00104 
00105     /** Destroy the I2S instance
00106      */
00107     ~I2S();
00108 
00109     /** Write to the FIFO
00110      *
00111      * @param buf[] The buffer of values to write: are bit stuffed in fours
00112      * @param len    The number of chars to write
00113      */
00114     void write(char buf[], int len);
00115 
00116     /** Write to the FIFO
00117      *
00118      * @param buf[] The buffer of values to write: are bit stuffed automatically
00119      * @param len    The number of chars to write
00120      */
00121     void write(int buf[], int len);
00122 
00123     /** Read the FIFOs contents
00124      *
00125      * @return The buffers value.
00126      */
00127     int read();
00128 
00129     /** Read from the FIFO
00130      *
00131      * @param buf[] The buffer of values to read: raw bit shifted
00132      * @param len    The number of chars to read
00133      */
00134     void read(char buf[], int len);
00135 
00136     /** Read from the FIFO
00137      *
00138      * @param buf[] The buffer of values to read: sorted to just values
00139      * @param len    The number of chars to read
00140      */
00141     void read(int buf[], int len);
00142 
00143     /** Get the maximum number of points of data the FIFO could store
00144      *
00145      * @return The number of points
00146      */
00147     int max_fifo_points();
00148     /** Switch the peripheral on and off
00149      *
00150      * @param pwr Power status
00151      */
00152     void power(bool pwr);
00153 
00154     /** Switch the peripheral between master and slave
00155      *
00156      * @param mastermode The peripherals master/slave status (I2S_MASTER/I2S_SLAVE)
00157      */
00158     void masterslave(bool mastermode);
00159 
00160     /** Switch the peripheral between different wordsizes
00161      *
00162      * @param words The number of bits per word: 8,16,32
00163      */
00164     void wordsize(int words);
00165 
00166     /** Define the MasterClk frequency
00167      *
00168      * @param freq The frequency desired for the MasterClk
00169      */
00170     void mclk_freq(int freq);
00171 
00172     /** Define the sample rate
00173      *
00174      * @param freq The desired sample rate frequency
00175      */
00176     void frequency(int freq);
00177 
00178     /** Set the level that the fifo interrupts at
00179      *
00180      * @param level A number between 0 and 7 at which the fifo interrupts
00181      */
00182     void set_interrupt_fifo_level(int level);
00183 
00184     /** Get the current FIFO level
00185      *
00186      * @return A number between 0 and 7 the FIFO is currently at
00187      */
00188     int fifo_level();
00189 
00190     /** Get the current number of samples in the FIFO
00191      *
00192     * @return A number showing how many samples are in the FIFO
00193      */
00194     int fifo_points();
00195 
00196     /** Set whether the peripheral is in stereo or mono mode: in mono the perifpheral sends out the same data twice
00197      *
00198      * @param stereomode Whether the peripheral is in stereo or mono: I2S_STEREO/I2S_MONO
00199      */
00200     void stereomono(bool stereomode);
00201 
00202     /** Mute the peripheral
00203      *
00204      */
00205     void mute();
00206 
00207     /** Set the mute status of the peripheral
00208      *
00209      * @param mute_en Set whether the mute is enabled
00210      */
00211     void mute(bool mute_en);
00212 
00213     /** Stop the peripheral
00214      *
00215      */
00216     void stop();
00217 
00218     /** Start the peripheral
00219      *
00220      */
00221     void start();
00222 
00223     /** Check the Clock and Pin setup went according to plan
00224      *
00225      * @return Setup okay?
00226      */
00227     bool setup_ok();
00228 
00229     /** Attach a function to be called when the FIFO triggers
00230      *
00231      * @param fptr A pointer to the function to be called
00232      */
00233     void attach(void (*fptr)(void))
00234     {
00235         if (_rxtx == I2S_TRANSMIT)
00236         {
00237             I2STXISR.attach(fptr);
00238             txisr = true;
00239         }
00240         else
00241         {
00242             I2SRXISR.attach(fptr);
00243             rxisr = true;
00244         }
00245     }
00246 
00247     /** Attach a member function to be called when the FIFO triggers
00248      *
00249      * @param tptr A pointer to the instance of the class
00250      * @param mptr A pointer to the member function
00251      */
00252     template<typename T>
00253     void attach(T *tptr, void (T::*mptr)(void))
00254     {
00255         if (_rxtx == I2S_TRANSMIT)
00256         {
00257             I2STXISR.attach(tptr, mptr);
00258             txisr = true;
00259         }
00260         else
00261         {
00262             I2SRXISR.attach(tptr, mptr);
00263             rxisr = true;
00264         }
00265     }
00266 
00267 private:
00268 
00269 void _set_clock_112896(void);
00270 void _set_clock_122800(void);
00271 void _i2s_init(void);
00272 void _i2s_set_rate(int smprate);
00273 
00274     void mclk_enable(bool mclk_en);
00275 
00276     void write_registers();
00277 
00278     void pin_setup();
00279 
00280     void fraction_estimator(float in, int * num, int * den);
00281 
00282     float mod(float in);
00283 
00284     void defaulter();
00285 
00286     PinName _SerialData, _WordSelect, _BitClk, _MasterClk;
00287     bool WordSelect_d, BitClk_d, MasterClk_d;
00288     bool _rxtx;
00289     bool pwr;
00290     bool master;
00291     int wordwidth;
00292     char wordwidth_code;
00293     bool mclk_en;
00294     int mclk_frequency;
00295     int freq;
00296     bool stereo;
00297     bool muted;
00298     bool stopped;
00299     int interrupt_fifo_level;
00300     int pin_setup_err;
00301     int reg_write_err;
00302     bool deallocating;
00303     int old_freq;
00304 
00305     bool fourwire;
00306 
00307     int old_pre_num;
00308     int old_pre_den;
00309     int old_bitrate_div;
00310     static void _i2sisr(void);
00311 
00312     static FunctionPointer I2STXISR;
00313     static FunctionPointer I2SRXISR;
00314 
00315     static bool txisr;
00316     static bool rxisr;
00317 
00318     void write(int bufr[], int bufl[], int len);
00319     void read(int bufr[], int bufl[], int len);
00320 };
00321 
00322 #endif