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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; }
This is from my code-monkey rule-book (aka "Rules for [Radcial] Code Monkeys")
I rarely give out this type of valuable information, so you (and every forum reader) better appreciate it...
COMMENTS
Generally "Comments" are either Strategic or Tactical in nature. While some comments can be categorized as Orientation.
Strategic comments describe what a section of code is supposed to accomplish. Strategic comments should be placed before the code section that implements the task.
Tactical comments describes the specifics on how the code is implementing a task. Typically these tactical comments are on an end-of -line basis. Tactical comments serve to enlighten the non-obvious behavior or method implemented, and not a re-statement of what the code performs:
Orientation and Strategic are closely related, but they do differ. Orientation comments provide the reader with a wider conceptual view of the code module. Orientation comments can be information about the system's environment like the OS, CPU, Memory, IDE, Versions, etc. While Strategic and Tactical are the dominant forms, Orientation should be still be contained in all source code modules.
The over-use of tactical comments will result in source code that takes too long to read, and begins to devalue and hide the worth-while comments. Strategic comments should be the primary and dominant form of commenting source code.
Tactical comments should be as detailed as needed to inform the programmer. The common used for Tactical comments is when describing the side-effects of code implementation or when the code performs something that is not obvious to the standard or novice programmer. Always write on a level that is explanatory the reader, and never assume the reader is as competent as you think you are.
Tactical comments in "C" typically use the double-slash notation, while the Strategic comments are flower-boxed. Orientation comments are typically found at the top of the module.
--Cpt. Vince Foster 2nd Cannon Place Fort Marcy Park, VA
thanks a lot for your valuable advice captain. i dont disagree with you at all, so, i am posting my commented version right away.
/* the routine for sending a start bit for i2c initialization */ void Write_Start(void) { E2P_SDA = 1; // sda is set high initially for a Hi to Low transition E2P_SCL = 1; // scl is made high delay_i2c(); // delay of 5 micro seconds E2P_SDA = 0; // sda is driven low to complete hi to low signal delay_i2c(); // delay of 5 micro seconds E2P_SCL = 0; // scl is then made low again to complete one clock period delay_i2c(); } /* this is used to write a byte onto the eeprom at location 0x5005 */ void Write_to_E2P(void) { unsigned char DEV_SEL_CODE = 0x0A0; // device select code unsigned char ADDR_MSB = 0x50; // MSB of address unsigned char ADDR_LSB = 0x05; // LSB of address unsigned char i; // loop variable Write_Start(); // I2C START for(i=7;i>=0;i--) // transmitting from the bit 7 down to bit 0 in the loop { E2P_SDA = DEV_SEL_CODE^i; // data bit on the sda line E2P_SCL = 0; // a rising edge of the pulse to sample the sda line delay_i2c(); E2P_SCL = 1; delay_i2c(); } E2P_SDA = 1; // these lines are for the 9th clock pulse when the slave pulls the sda line low E2P_SCL = 0; delay_i2c(); E2P_SCL = 1; delay_i2c(); delay_i2c(); E2P_SCL = 0; delay_i2c(); if(E2P_SDA == 0) // if the acknowledge is recieved then we glow an LED used for debugging on board LED1=1; /* the same story follows for the rest three bytes, which are - the address MSB and LSB and the data byte to be transferred */ 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 = data_byte^i; // data_byte is a global variable 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; }
[Waffle snipped]
I preferred it when you kept you secrets to yourself.
I preferred it when you kept you<sic> secrets to yourself.
.. went by the sardines preferences there would be no discussion, since the sardine only prefer his own opinion.
anyhow, since the sardine is so impressed with his own reading of C books, I suggest he nest read a grammar book.
Erik
Some things aren't secret anymore.
(Video of one of MY babies...) [2minutes and 13 seconds] " far exceeds mine.
Exquisite.
(Video of one of MY babies...)
Does your mum know you use Google after bedtime, Vince?