I2C-24C04 and buzzer This program problem

QWE4562009

I2C-24C04 and buzzer This program problem [Copy link]

I2C-24C04 and buzzer program problem

/* Name: I2C-24C04 and buzzer

Description: The program first writes a musical note to the 24C04 , then reads it and plays it.

*/

#include<reg51.h>

#include<intrins.h>

#define uchar unsigned char

#define uint unsigned int

#define NOP4() {_nop_();_nop_();_nop_();_nop_();}

sbit SCL=P1^0;

sbit SDA=P1^1;

sbit SPK=P3^0;

// Delay table corresponding to standard note frequency

uchar code HI_LIST[]={0,226,229,232,233,236,238,240,241,242,244,245,246,247,248};

uchar code LO_LIST[]={0,4,13,10,20,3,8,6,2,23,5,26,1,4,3};

// The note to be written into 24C04

uchar code Song_24C04[]={1,2,3,1,1,2,3,1,3,4,5,3,4,5};

uchar sidx; // Read the note index

// Delay

void DelayMS(uint ms)

{

flying i;

while(ms--) for(i=0;i<120;i++);

}

//IIC starts

void Start()

{

SDA=1;SCL=1;NOP4();SDA=0;NOP4();SCL=0;

}

//IIC stop

void Stop()

{

SDA=0;SCL=0;NOP4();SCL=1;NOP4();SDA=1;

}

// Read the response

void RACK()

{

SDA=1;NOP4();SCL=1;NOP4();SCL=0;

}

// Send a non-response signal

void NO_ACK()

{

SDA=1;SCL=1;NOP4();SCL=0;SDA=0;

}

// Write a byte of data to 24C04

void Write_A_Byte(uchar b)

{

flying i;

for(i=0;i<8;i++)

{

b<<=1;SDA=CY;_nop_();SCL=1;NOP4();SCL=0;

}

RACK();

}

// Write data to the specified address

void Write_IIC(uchar addr,uchar dat)

{

Start();

Write_A_Byte(0xa0);Write_A_Byte(addr);Write_A_Byte(dat);

Stop();

DelayMS(10);

}

// Read a byte of data from 24C04

uchar Read_A_Byte()

{

flying i,b;

for(i=0;i<8;i++)

{

SCL=1;b<<=1;b|=SDA;SCL=0;

}

return b;

}

// Read data from the current address

uchar Read_Current()

{

uchar d;

Start();

Write_A_Byte(0xa1);d=Read_A_Byte();NO_ACK();

Stop();

return d;

}

// Read data from any address

uchar Random_Read(uchar addr)

{

Start();

Write_A_Byte(0xa0);Write_A_Byte(addr);

Stop();

return Read_Current();

}

// Timer 0 interrupt

void T0_INT() interrupt 1

{

SPK=~SPK;

TH0=HI_LIST[sidx];

TL0=LO_LIST[sidx];

}

// Main program

void main()

{

uint i;

IE=0x82;

TMOD=0x00;

for(i=0;i<14;i++) // Write the note table to 24C04

{

Write_IIC(i,Song_24C04);

}

while(1) // repeatedly read and play notes

{

for(i=0;i<15;i++) // Read notes from 24C04

{

sidx=Random_Read(i); // Read from the specified address

TR0=1; // play

DelayMS(300);

}

}

}

question:

1.#define NOP4() {_nop_();_nop_();_nop_();_nop_();}//-------- I don't understand what this macro definition means

2. Write_IIC(i,Song_24C04 );//---------------- What does i,Song_24C04 mean? Why is there another [ ]

3.uchar code HI_LIST[]={0,226,229,232,233,236,238,240,241,242,244,245,246,247,248};

uchar code LO_LIST[]={0,4,13,10,20,3,8,6,2,23,5,26,1,4,3};----------------- What do the numbers in these brackets mean?

4. //IIC starts

void Start()

{

SDA=1;SCL=1;NOP4();SDA=0;NOP4();SCL=0;

}

-----------------NOP4();SDA=0;NOP4();SCL=0;How do you understand this?

5. // Write data to the specified address

void Write_IIC(uchar addr,uchar dat)

{

Start();

Write_A_Byte(0xa0);Write_A_Byte(addr);Write_A_Byte(dat);

Stop();

--------------- Why is there a hexadecimal number in the first function bracket, and what does addr and dat mean after that?

freebsder

4 no operations, no operations are assembly. [] Array, curly brackets are the static array initialization method after c99, I forgot the specific name @lcofjp . SCL, SDA correspond to two IOs, 1 is pulled high, 0 is set low, simulating the timing and data of iic. 0xa0 is fixed, just write it in.

QWE4562009

freebsder posted on 2020-7-14 14:32 4 empty operations, empty operations are assembly. [] Array, curly braces are the static array initialization method after c99, I forgot the specific name @lcofjp &nbs ...

I mean what do the values in the array mean?

freebsder

QWE4562009 posted on 2020-7-14 15:43 I mean what do the values in the array mean?

// Delay table corresponding to standard note frequency

lcofjp

freebsder posted on 2020-7-14 14:32 4 empty operations, empty operations are assembly. [] Array, curly braces are the static array initialization method after c99, I forgot the specific name @lcofjp &nbs ...

For me who writes js, doesn't C language always support initialization in curly braces?

freebsder

lcofjp posted on 2020-7-14 23:37 For me who writes js, doesn't C language always support initialization in curly braces?

I have no impression, it seems that this method was only supported later.

lcofjp

freebsder posted on 2020-7-15 13:32 I don’t remember, it seems that this method was only supported later.

I think you are confusing it with the structure.

freebsder

lcofjp posted on 2020-7-15 20:55 I suspect you are confused with the structure

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