Mini2440 bare metal test IIS - music player

IIS

Signal frequency setting

IIS (Inter-IC Sound) was developed by Philips and is a commonly used audio device interface, mainly used for CD, MD, MP3 and other devices.

S3C2440 has a total of 5 pins for IIS: IISDO, IISDI, IISSCLK, IISLRCK and CDCLK. The first two pins are used for the output and input of digital audio signals, and the other three pins are related to the frequency of the audio signal. It can be seen that to use IIS well, the signal frequency must be set correctly.

IISSCLK is a serial clock, and each clock signal transmits one bit of audio signal. Therefore, the frequency of IISSCLK = number of channels × sampling frequency × number of sampling bits. For example, if the sampling frequency fs is 44.1kHz, the number of sampling bits is 16 bits, and the number of channels is 2 (left and right channels), then the frequency of IISSCLK = 32fs = 1411.2kHz.

1. Fs 2. Number of sampling bits 3. Number of channels

View using wav data extractor

Sampling frequency

Right click the music file --> Properties --> Details

PCLK (50,000,000) is processed by two prescalers to obtain IISSCLK, IISLRCK and CDCLK respectively. Register IISPSR is the IIS prescaler register, bits 5 to 9 are prescaler A, bits 0 to 4 are prescaler B. Generally speaking, the values ​​N of these two prescalers are equal, that is, as long as one is known, the other is also known. Here we calculate the value N of prescaler B through CDCLK, that is, CDCLK = PCLK / (N + 1).

I set the main clock frequency to 384fs. From the table below, since fs=44.1kHZ, CDCLK=16.9344, we know that N=2.

//The prescaler is 2, so CDCLK=PCLK/(2+1)=16.66666kHz (the closer to 16.9344 in the table, the better)

    rIISPSR = 2<<5|2;

IIS Configuration

//Configure IIS interface

    rGPEUP = rGPEUP & ~(0x1f) | 0x1f; //Pull-up is invalid, GPE[4:0] 1 1111

    rGPECON = rGPECON & ~(0x3ff) | 0x2aa;

    //Configure IIS registers for s3c2440

    //The prescaler is 2, so CDCLK=PCLK/(2+1)=16.66666kHz

    rIISPSR = 2<<5|2;

    //Invalid DMA, input idle, prescaler valid, turn on IIS

    rIISCON = (0<<5)|(0<<4)|(0<<3)|(1<<2)|(1<<1);   

    //PCLK is the clock source, output mode, IIS mode, 16 bits per channel, CODECLK=384fs, SCLK=32fs

    rIISMOD = (0<<9)|(0<<8)|(2<<6)|(0<<5)|(0<<4)|(1<<3)|(1<<2)|(1<<0);     

    rIISFCON = (0<<15)|(1<<13); //Output FIFO normal mode, output FIFO enable

UDA1341

In my opinion, IIS is to send audio (WAV) data of a certain size to FIFO or DMA at a certain frequency, and UDA1341 is to convert these audio data into electrical signals and send them out through the audio interface. The configuration of uda1341 is for reference.

//Simulate L3 bus to write data through io port  

//mode: 1 is address mode, 0 is data mode  

//Please refer to the data sheet for address mode, data mode and transmission timing  

static void write_UA1341(U8 data, U8 address)  

{  

    int i,j;  

    if(address == 1) {  

        rGPBDAT = rGPBDAT&(~(L3D | L3M | L3C)) | L3C; //Address mode, according to the manual, L3M is LOW, L3C is high  

    } else {  

       rGPBDAT = rGPBDAT & (~(L3D |L3M |L3C)) |(L3M|L3C); //Data mode L3M is high  

    }  

    Delay(1);  

    //transfer data  

   for(i=0;i<8;i++)    

       {

              if(data & 0x1) // H

              {

                     rGPBDAT &= ~L3C; //L3C=L

                     rGPBDAT |= L3D; //L3D=H            

                     for(j=0;j<5;j++)

; //Wait for a while

                     rGPBDAT |= L3C; //L3C=H

                     rGPBDAT |= L3D; //L3D=H

                     for(j=0;j<5;j++)

; //Wait for a while

               }

              else // L

              {

                     rGPBDAT &= ~L3C; //L3C=L

                     rGPBDAT &= ~L3D; //L3D=L

                     for(j=0;j<5;j++)

; //Wait for a while

                     rGPBDAT |= L3C; //L3C=H

                     rGPBDAT &= ~L3D; //L3D=L

                     for(j=0;j<5;j++)

; //Wait for a while          

              }

              data >>= 1;

        }

    rGPBDAT = rGPBDAT & ~(L3D | L3M | L3C) | (L3C | L3M); //L3M=H,L3C=H  

UDA1341 initialization

// UDA1341 initialization

    //Configure L3 interface bus, GPB2:L3MODE, GPB3:L3DATA, GPB4:L3CLOCK

    rGPBCON = 0x015550; //output

    rGPBUP = 0x7ff; //Pull-up is invalid

    rGPBDAT = 0x1e4;

    rGPBDAT = rGPBDAT & (~(L3M |L3C |L3D)) |(L3M|L3C); //Set L3CLOCK and L3MODE high to prepare for transmission  

    ////According to the operation sequence in page 14 of the UDA1341TS data sheet, first in address mode,  

    //Select operation address 000101xx +10(STATUS)=0X16  

    write_UA1341(0x16,1);    

    write_UA1341(0x60,0); // 0, 1, 10, 000, 0 reset  

    write_UA1341(0x16,1);  

    write_UA1341(0x10,0); //0,0,01, 000,0 : status 0, 384fs, IIS, no DC-filtering  

    write_UA1341(0x16,1);  

    write_UA1341(0xc1,0); //1,0,0,0, 0,0,01: status 1,                                    

                                //Gain of DAC 6 dB,Gain of ADC 0dB,ADC non-inverting,  

                                //DAC non-inverting, Single speed playback, ADC-Off DAC-On 

Interface material

Production of WAV audio files

1. Download lossless music from the Internet (I downloaded WAV and APE formats)

2. Open Format Factory → Audio → WAV → Add File → Capture a clip (lossless music is too large, so you need to capture a small part, 20 seconds per song will be enough) → OK → Output Configuration (as shown below) → OK → Click Start.

3. Open the captured WAV folder

4. Use DataToHex to convert the WAV file into an audio data array file, and modify the array file name Array[].

5. Change the wav audio data file to a c file. Please do not change it to h, otherwise debugging will take a long time.

6. Production is complete!

Main logic blocks

buffer=music1; //Initialize buffer to point to music1 music array address

    while(1){

        if(flag==1){ rIISCON |= 0x1; //If you click play (flag==1) to turn on IIS song_num1 initial value is 1 to play the first song

         //Process the display of music pictures when clicking to play (flag1=1 when clicking to play)

        if(flag1==1 && song_num==1 ){flag1=0, Pait_Bmp( 70, 70, 100, 100, music1_bmp);}

        if(flag1==1 && song_num==2 ){flag1=0, Pait_Bmp( 70, 70, 100, 100, music2_bmp);}

        if(flag1==1 && song_num==3 ){flag1=0, Pait_Bmp( 70, 70, 100, 100, music3_bmp);}

       // When the music flag song_num1 is not zero (song_num1 is assigned a value after the song is played or song_num1 is assigned a value through a key value (previous/next song)) 

       // buffer music playback address is initialized length music length is reassigned and music picture is displayed next FIFO byte position count is initialized song_num1 is reset to zero

        if(song_num1==1) { buffer=music1; length=3704572; count=0; Pait_Bmp( 70, 70, 100, 100, music1_bmp); song_num1=0;}

        if(song_num1==2) { buffer=music2; length=3704552; count=0; Pait_Bmp( 70, 70, 100, 100, music2_bmp); song_num1=0;}

        if(song_num1==3) { buffer=music3; length=5644880; count=0; Pait_Bmp( 70, 70, 100, 100, music3_bmp); song_num1=0;}

        if((rIISCON & (1<<7))==0) //Check if the output FIFO is empty

            { //The data in FIFO is 16 bits and the depth is 32

            //When the output FIFO is empty, write 32 16-bit data to the FIFO at one time

                for(i=0;i<32;i++){

                //rIISFIFO=(buffer[i+count]);

                rIISFIFO=(buffer[2*i+count])+(buffer[2*i+1+count]<<8); // Store 16 bits of data in FIFO in one cycle  

  }                           

                count+=64;                                                

                                              // 64 is 32 loops, each loop points to the sum of two different bytes

        //After the music is finished playing, the music flag song_num1 points to the next song

        if(count>length){   

            song_num2=song_num2+1; 

            if(song_num2==4){song_num2=1;} 

            song_num1=song_num2;

            }

        }

        }

        //Close IIS when paused to display the welcome picture

        if(flag==0) { rIISCON |= 0x0; Pait_Bmp( 70, 70, 100, 100, hellomusic); } //Close IIS;        

    }

Main code

Main.c

#define GLOBAL_CLK 1

#include "def.h"

#include "option.h"

#include "2440addr.h"

#include "2440lib.h" //Function declaration

#include "2440slib.h"

#include "mmu.h"

#include "profile.h"

// Function declaration 

extern void music_player(void);

void Main(void)

{       

    U32 mpll_val = 0,consoleNum;

    Port_Init();

    mpll_val = (92<<12)|(1<<4)|(1);

    //init FCLK=400M,

    ChangeMPllValue((mpll_val>>12)&0xff, (mpll_val>>4)&0x3f, mpll_val&3);

    ChangeClockDivider(14, 12); //the result of rCLKDIVN [0:1:0:1] 3-0 bit

    cal_cpu_bus_clk(); //HCLK=100M PCLK=50M

    consoleNum = 0; // Uart 0 select for debug.

    Uart_Init( 0,115200 );

    Uart_Select(consoleNum);

    Port_Init();

    MMU_Init(); //Address mapping initialization

Beep(2000, 100);   

    music_player();

}

music_player.c

/***********************************

 Implementing the function music player  

***************************************/

#include "2440lib.h"

#include "2440slib.h" 

#include "LCD_init.h"

#include "2440addr.h" 

#define L3C (1<<4) //gpb4:L3CLOCK  

#define L3D (1<<3) //gpb3:L3DATA  

#define L3M (1<<2) //gpb2:L3MODE 

#define rIISFIFO (*(volatile unsigned long*)0x55000010)  

extern unsigned char music_interface[];

extern unsigned char hellomusic[]; //hellomusic

extern unsigned char music1_bmp[];

extern unsigned char music2_bmp[];

extern unsigned char music3_bmp[];

extern unsigned char button1[]; //Pause

extern unsigned char button1_1[];

extern unsigned char button2[]; //Next song

extern unsigned char button2_2[];

extern unsigned char button3[]; //Previous song

extern unsigned char button3_3[];