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Program to write and read a byte between P89V51RD2 and ST M24C64

Hello All,

I am finding it really hard to perform write and read operations on the EEPROM connected to the MCU by two wires using the I2C Protocol.

I've read the data sheets, written the code exactly matching the datasheet info, but it was of no avail.

Please help me out.

My code looks something like this

void Write_Start(void)
        {
                E2P_SDA = 1;
                E2P_SCL = 1;
                delay_i2c();
                E2P_SDA = 0;
                delay_i2c();
                E2P_SCL = 0;
                delay_i2c();
        }

void Write_to_E2P(void)
        {
                unsigned char DEV_SEL_CODE = 0x0A0;
                unsigned char ADDR_MSB = 0x50;
                unsigned char ADDR_LSB = 0x05;
                unsigned char i;

                Write_Start();

                for(i=7;i>=0;i--)
                        {
                                E2P_SDA = DEV_SEL_CODE^i;
                                E2P_SCL = 0;
                                delay_i2c();
                                E2P_SCL = 1;
                                delay_i2c();
                        }

                E2P_SDA = 1;
                E2P_SCL = 0;
                delay_i2c();
                E2P_SCL = 1;
                delay_i2c();
                delay_i2c();
                E2P_SCL = 0;
                delay_i2c();

                if(E2P_SDA == 0)
                        LED1=1;

                for(i=7;i>=0;i--)
                        {
                                E2P_SDA = ADDR_MSB^i;
                                E2P_SCL = 0;
                                delay_i2c();
                                E2P_SCL = 1;
                                delay_i2c();
                        }

                E2P_SDA = 1;
                E2P_SCL = 0;
                delay_i2c();
                E2P_SCL = 1;
                delay_i2c();
                delay_i2c();
                E2P_SCL = 0;
                delay_i2c();

                if(E2P_SDA == 0)
                        LED2=1;

                for(i=7;i>=0;i--)
                        {
                                E2P_SDA = ADDR_LSB^i;
                                E2P_SCL = 0;
                                delay_i2c();
                                E2P_SCL = 1;
                                delay_i2c();
                        }

                E2P_SDA = 1;
                E2P_SCL = 0;
                delay_i2c();
                E2P_SCL = 1;
                delay_i2c();
                delay_i2c();
                E2P_SCL = 0;
                delay_i2c();

                if(E2P_SDA == 0)
                        LED3=1;

                for(i=7;i>=0;i--)
                        {
                                E2P_SDA = current_channel^i;
                                E2P_SCL = 0;
                                delay_i2c();
                                E2P_SCL = 1;
                                delay_i2c();
                        }

                E2P_SDA = 1;
                E2P_SCL = 0;
                delay_i2c();
                E2P_SCL = 1;
                delay_i2c();
                delay_i2c();
                E2P_SCL = 0;
                delay_i2c();

                if(E2P_SDA == 0)
                        LED4=1;


        }

Parents
  • But many "I wouldn't start from there" do bring forward good information.

    In this case: It is normally better to use a controller with I2C than to implement it in software. And today, there is no correlation between controller price and the availability of a I2C controller.

    Another interesting thing is the answer we got:
    "i am using a DIP Package. My board is designed for that."

    Quite a number of 8051 chips are available in a DIP package. Quite a number of development boards with 40-pin DIP sockets are intended for use with quite a number of different 8051 chips, as long as care is taken with supply voltages, crystal frequency and similar.

    A much better reason for not considering alternatives would have been: "The controller is soledred on my development board, and I don't have the equipment to replace it with another, and can't afford buying another development board."

    Another good reason for staying with bit-banging would have been: "My assignment is to implement a software-only solution, to prove that I understand the protocol."

Reply
  • But many "I wouldn't start from there" do bring forward good information.

    In this case: It is normally better to use a controller with I2C than to implement it in software. And today, there is no correlation between controller price and the availability of a I2C controller.

    Another interesting thing is the answer we got:
    "i am using a DIP Package. My board is designed for that."

    Quite a number of 8051 chips are available in a DIP package. Quite a number of development boards with 40-pin DIP sockets are intended for use with quite a number of different 8051 chips, as long as care is taken with supply voltages, crystal frequency and similar.

    A much better reason for not considering alternatives would have been: "The controller is soledred on my development board, and I don't have the equipment to replace it with another, and can't afford buying another development board."

    Another good reason for staying with bit-banging would have been: "My assignment is to implement a software-only solution, to prove that I understand the protocol."

Children
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