51 single chip simple waveform generator (sine wave, sawtooth wave, triangle wave)

The following is the source code of the simple waveform generator of 51 single-chip microcomputer:

#include

#include

#define ADDR1 0x2c //MAX5820LEUA

sbit key_sin=P1^0;

sbit key_tran=P1^2;

sbit key_tooth=P1^4;

sbit SCL = P2 ^ 0;

sbit SDA = P2 ^ 1;

unsigned char code sin[256]= //sine table

        {

        0x80,0x83,0x86,0x89,0x8d,0x90,0x93,0x96,0x99,0x9c,0x9f,0xa2,0xa5,0xa8,0xab,0xae,0xb1,0xb4,0xb7,0xba,0xbc,0xbf,0xc2,0xc5,

        0xc7,0xca,0xcc,0xcf,0xd1,0xd4,0xd6,0xd8,0xda,0xdd,0xdf,0xe1,0xe3,0xe5,0xe7,0xe9,0xea,0xec,0xee,0xef,0xf1,0xf2,0xf4,0xf5,

        0xf6,0xf7,0xf8,0xf9,0xfa,0xfb,0xfc,0xfd,0xfd,0xfe,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xfe,0xfd,

        0xfd,0xfc,0xfb,0xfa,0xf9,0xf8,0xf7,0xf6,0xf5,0xf4,0xf2,0xf1,0xef,0xee,0xec,0xea,0xe9,0xe7,0xe5,0xe3,0xe1,0xde,0xdd,0xda,

        0xd8,0xd6,0xd4,0xd1,0xcf,0xcc,0xca,0xc7,0xc5,0xc2,0xbf,0xbc,0xba,0xb7,0xb4,0xb1,0xae,0xab,0xa8,0xa5,0xa2,0x9f,0x9c,0x99,

        0x96,0x93,0x90,0x8d,0x89,0x86,0x83,0x80,0x80,0x7c,0x79,0x76,0x72,0x6f,0x6c,0x69,0x66,0x63,0x60,0x5d,0x5a,0x57,0x55,0x51,

        0x4e,0x4c,0x48,0x45,0x43,0x40,0x3d,0x3a,0x38,0x35,0x33,0x30,0x2e,0x2b,0x29,0x27,0x25,0x22,0x20,0x1e,0x1c,0x1a,0x18,0x16,

        0x15,0x13,0x11,0x10,0x0e,0x0d,0x0b,0x0a,0x09,0x08,0x07,0x06,0x05,0x04,0x03,0x02,0x02,0x01,0x00,0x00,0x00,0x00,0x00,0x00,

        0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x02,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0a,0x0b,0x0d,0x0e,0x10,0x11,0x13,0x15,

        0x16,0x18,0x1a,0x1c,0x1e,0x20,0x22,0x25,0x27,0x29,0x2b,0x2e,0x30,0x33,0x35,0x38,0x3a,0x3d,0x40,0x43,0x45,0x48,0x4c,0x4e,

        0x51,0x55,0x57,0x5a,0x5d,0x60,0x63,0x66,0x69,0x6c,0x6f,0x72,0x76,0x79,0x7c,0x80

        };

bit write_addr(unsigned char,bit); //The first parameter indicates the address, the second parameter indicates read: 1 write: 0

bit write_data(unsigned char); //The first parameter indicates the data, the second parameter indicates the command word

void stop();

void Delay(unsigned int);

I2C_Delay(unsigned int I2C_VALUE)

{       

        while ( --I2C_VALUE!= 0 );

}

/*

Function: I2C_Init()

Function: Initialize the I2C bus and put the bus in an idle state

Note: This function should usually be executed once at the beginning of the main() function.

*/

void I2C_Init()

{

        SCL = 1;

        I2C_Delay(5);

        SDA = 1;

        I2C_Delay(5);

}

/*

Function: I2C_Start()

Function: Generate the start state of the I2C bus

illustrate:

When SDA has a falling edge while SCL is at a high level, the I2C bus is started

Regardless of the level of SDA and SCL, this function can always correctly generate the start state.

This function can also be used to generate repeated start states.

After this function is executed, the I2C bus is in a busy state.

*/

void I2C_Start()

{

        SDA = 1;

        I2C_Delay(5);

        SCL = 1;

        I2C_Delay(5);

        SDA = 0;

        I2C_Delay(5);

        SCL = 0;

        I2C_Delay(5);

}

/*

Function: I2C_Write()

Function: Write 1 byte of data to the I2C bus

parameter:

dat: data to be written to the bus

*/

void I2C_Write(char dat)

{

        unsigned char t = 8;

        do

        {

                SDA = (bit)(dat & 0x80);

                dat <<= 1;

                SCL = 1;

                I2C_Delay(5);

                SCL = 0;

                I2C_Delay(5);

        } while ( --t != 0 );

}

bit I2C_GetAck()

{

        bit ack;

        SDA = 1;

        I2C_Delay(5);

        SCL = 1;

        I2C_Delay(5);

        ack = SDA;

        SCL = 0;

        I2C_Delay(5);

        return ack;

}

void I2C_Stop()

{

        unsigned int t = 10;

        SDA = 0;

        I2C_Delay(5);

        SCL = 1;

        I2C_Delay(5);

        SDA = 1;

        I2C_Delay(5);

        while ( --t != 0 ); // Add a certain delay before the next Start is generated

}

void Delay(unsigned int I2C_Delay_t)

{       

        while ( --I2C_Delay_t!= 0 );

}

bit write_addr(unsigned char addr,bit mod)

{

        unsigned char address;

        address=addr<<1;

        if(mod)

                address++;

        I2C_Start();

        I2C_Write(address);

        Delay(10);

        if(I2C_GetAck())

                return 1;

        return 0;

}

bit write_data(unsigned char dat)

{

        I2C_Write(dat);

        if(I2C_GetAck())

                return 1;

        return 0;

}

void stop()

{

        I2C_Stop();

        I2C_Heat();

}

void main(void)

{

        unsigned char i;

        loop:

        I2C_Heat();

        while(1)

        {

                if(key_sin==0) //Generate a sine wave

                {

                        while(1)

                        {

                                for(i=192;i<255;i++)

                                {

                                        write_addr(ADDR1,0);

                                        write_data(0);

                                        write_data(sin[i]);

                                        stop();

                                        if(!(key_tran!=0&&key_tooth!=0))

                                                goto loop;

                                }

                                for(i=0;i<192;i++)

                                {

                                        write_addr(ADDR1,0);

                                        write_data(0);

                                        write_data(sin[i]);

                                        stop();

                                        if(!(key_tran!=0&&key_tooth!=0))

                                                goto loop;

                                }

                        }

                }

                if(key_tran==0) //Generate triangle wave

                {

                        while(1)

                        {

                                 for(i=0;i<255;i++)

                                {

                                        write_addr(ADDR1,0);

                                        write_data(0);

                                        write_data(i);

                                        stop();

                                        if(!(key_sin!=0&&key_tooth!=0))

                                                goto loop;

                                }

                                for(;i>0;i--)

                                {

                                        write_addr(ADDR1,0);

                                        write_data(0);

                                        write_data(i);

                                        stop();

                                        if(!(key_sin!=0&&key_tooth!=0))

                                                 goto loop;

                                }

                        }

                }

                if(key_tooth==0) //Generate sawtooth wave

                {

                        while(1)

                        {

                                 for(i=0;i<255;i++)

                                {

                                        write_addr(ADDR1,0);

                                        write_data(0);

                                        write_data(i);

                                        stop();

                                        if(!(key_tran!=0&&key_sin!=0))

                                                goto loop;

                                }

                        }

                }       

        }

}