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TMS320F280049C: I2C fifo with CSI 24c16 EEPROM

Ashish Bhoi
Intellectual 375 points
Part Number: TMS320F280049C
Other Parts Discussed in Thread: C2000WARE

Hello TI team,

I am working on I2C driver, I have managed to get i2c fifo working and fifo Tx, fifo Rx interrupts working. I am getting interrupts properly.

My problem is that when I try to read EEPROM I am going to some random address value and not getting to proper memory location what I want

Currently for reading I am following below steps in my Read operation (* Module is disabled in step 1)

  • I am setting slave addr(0x50) and then I am making TRX to 1 for Transmitting address value and MST = 1 and load register address in my global array in my Transmit function
  • Then I am enabling module (IRS = 1), I am loading data before Enabling module as my TXFIFO level is set to 0.
  • Now Tx interrupt HITS and data(memory addr which I want to access) is loaded into I2CDXR register(fifo buffer) 
  • Then push 1 start condition by setting STT
  • I am setting TRX bit to 0 for read, MST = 1 and then I am setting Slave address(0x50)  in register
  • I am getting Rx interrupt but data in I2CDRR register is not which I wrote there using MY WRITE FUNCTION.

My write function is working as I can see values which I loaded, I can only see this values when I do multiple time read (So I know data is written in EEPROM) (it is new EEPROM so all data bits must be 1)

I suspect that write might also not accessing correct address which I am passing or wish to write.

SO PLEASE TELL ME HOW DO I ACCESS CORRECT LOCATION, WHAT AM I MISSING ?

What I want to do is write and read from specific locations.

My code is pretty generic as it should work with sensors, eeprom and other i2c supporting devices.

  • 0
    Intellectual 375 points

    P.S. Repeat mode is enabled
    If you want to look at code I can share in personal message not in public.

  • 0 in reply to Ashish Bhoi
    TI__Guru 55700 points

    Ashish,

    What is the write cycle time specified in your EEPROM? Typically, after I2C transmits a data to be programmed into a specific address, it takes finite amount of time (defined by EEPROM statemachine) to program data into EEPROM address. This is generally specified as write cycle time. If you don't wait for write cycle time you will read incorrect data.

    I2C Write function transmits START condition + EEPROM address with Write bit set + data + STOP condition

    Wait for Write cycle time specified in EEPROM datasheet

    I2C read function transmit START condition + EEPROM address with read bit set + data from slave + STOP condition

    Regards,

    Manoj

  • 0 in reply to Manoj Santha Mohan
    Intellectual 375 points

    Adding more delay is not helping sir.


    As earlier I told I am able to write data to EEPROM I know because I can see values which I uploaded with write function while reading EEPROM in random order.

    My issue is I can not read from specific address.

  • 0 in reply to Ashish Bhoi
    Intellectual 375 points

    I have shared my code in personal message, Please have a look into it.

  • 0 in reply to Ashish Bhoi
    TI__Guru 55700 points

    Ashish,

    RandomRead needs master transmitter (which transmits EEPROM address to be read) + Repeated start in master receiver mode to read EEPROM contents as shown below. Your example doesn't seem to show master transmitter + master receiver. I just see master receiver mode.

    Regards,

    Manoj

  • 0 in reply to Manoj Santha Mohan
    Intellectual 375 points

    Hii Manoj,

    Can you please tell what I should be doing ?

    Currently I am trying to do below

    I want to first send reigster address to slave from which I want to read (Master_Transmitter - transmit memory addr and slave addr & TRX=1)

    Then a start condition I am sending

    Then I am calling master_receiver function with a Repeated start condition and I am getting some data from EEPROM back.

    This step I am trying to implement but it look thats not happening Register/memory address which I want to read that address is not going I think

    Please let me know to send a Random Read Request properly with my code.

    Thanks and regards
    Ashish Bhoi

  • 0 in reply to Ashish Bhoi
    TI__Guru 55700 points

    Which EEPROM are you using?

    Please send SCL / SDA scope shot using I2C protocol analyzer.

  • 0 in reply to Manoj Santha Mohan
    Intellectual 375 points

    I am using  CSI 24C16 EEPROM device, slave address 0x50.

    I do not have I2C protocol analyzer, I can send you scope shot from Oscilloscope.

  • 0 in reply to Ashish Bhoi
    TI__Guru 55700 points

    Ashish,

    I have clearly specified in the I2C logic analyzer image on how exactly you need to perform EEPROM random read.

    Did you check with EEPROM manufacturer whether you are sending the address in right format? Does your EEPROM expect the address in the same format?

    Regards,

    Manoj

  • 0 in reply to Manoj Santha Mohan
    Intellectual 375 points

    Hello Manoj,

    Here is snapshots from Datasheet of my EEPROM, in here RandomRead is named by selective read

    As you can see it is sending 8 address bits and 8 data bits.

  • 0 in reply to Ashish Bhoi
    Intellectual 375 points

    I need to resolve this issue fast Mr. Manoj please help me, have you taken a look into my code,

    where should I make update that I want to know Sir.

    Is the way I am sending start and stop conditions are is correct.

  • 0 in reply to Ashish Bhoi
    TI__Guru 55700 points

    I did briefly review your code, I don't think you have got I2C write / read function correctly. Please use the pseudo code shown below to configure to I2C Write / Read functions. This assumes that you are using I2C FIFO.

    Here is the pseudo code for I2C_Write_byte

    1) Configure I2C in master transmitter mode with repeat mode enabled

    2) Write EEPROM slave address (0x50 for EEPROM I have) to I2CSAR register

    3) Generate START condition by setting I2CMDR.STT = 1

    4) Write EEPROM address to I2CDXR register  (Lets say you are trying to write to EEPROM address 0x20, then you need to write 0x20 in I2CDXR register)

    5) Write data to be written into EEPROM into I2CDXR register (Lets say we are trying to write to EEPROM address 0x20 = data)

    6) Wait till I2CTX FIFO is empty (I2CFFTX.TXFFST = 0?)

    7) Once TXFIFO gets empty generate STOP condition (I2CMDR.STP = 1)

    Here is the pseudo code for I2C_Read_byte (Random Read)

    This code is divided into two portions

    A) First is Master transmitter portion to transmit the EEPROM address to read from

    1) Configure I2C in master transmitter mode with repeat mode enabled

    2) Write EEPROM slave address (0x50 for EEPROM I have) to I2CSAR register

    3) Generate START condition by setting I2CMDR.STT = 1

    3) Write EEPROM address to I2CDXR register  (EEPROM address to read from)

    4) Wait till I2CTX FIFO is empty (I2CFFTX.TXFFST = 0?)

    B) Second is Master receiver portion to receive the data from EEPROM

    1) Configure I2C in master receiver mode with repeat mode enabled

    2) Generate START condition by setting I2CMDR.STT = 1 (This is your repeated start condition)

    3) Wait till I2CRXFIFO has received a byte (I2CFFTX.RXFFST = 1?)

    4) Read I2XDRR register //This data stored in EEPROM address

    5) Generate STOP condition (I2CMDR.STP  = 1)

     

    Regards,

    Manoj

  • 0 in reply to Manoj Santha Mohan
    TI__Guru 55700 points

    Ashish,

    We have released new I2C example which shows how to talk to EEPROM using both polling and interrupt method. Please check those example in below path.

    You can easily modify this to other I2C interfaces like temp sensors, NOR flash etc.

    EEPROM polling method

    <C2000Ware>\\driverlib\f28004x\examples\i2c\i2c_ex4_eeprom_polling

    EEPROM interrupt method

    <C2000Ware>\\driverlib\f28004x\examples\i2c\i2c_ex4_eeprom_interrupt

    Regards,

    Manoj