Programming to external EEPROM

I never worked with SPI but rather with I2C, so I don't know for sure. I think that your datasheet might tell you what you need to place on the data bus and what you need to place on the address bus in order to communicate with your device. A simple assignment into a memory mapped region will get the job done.

I never worked with SPI but rather with I2C, so I don't know for sure. I think that your datasheet might tell you what you need to place on the data bus and what you need to place on the address bus in order to communicate with your device. A simple assignment into a memory mapped region will get the job done.

Perhaps you would like to look at the application note on the Infineon web site...

Interfacing the XC16x Microcontroller to a Serial SPI EEPROM -description (ap1609510_XC16x_SPI_EEPROM.pdf)

There is a pdf with code.

www.infineon.com/.../channel.html

Hello Chris,
I have seen your program in the website of Infineon, and its compiler is Tasking and mine is Keil uVision. Do you have the same proyect but for my compiler?
Thanks

Pfff, i'm so desperated. This program is very difficult to understand... I have been so long trying to undestand it. Is there any simple program that might help me?
Thanks

Hi

I am not sure what are the difficulties but I modified some code I made previously to Keil. I then tested it on an XC164CS starterkit without issue. If you want to post your email then I will send it to you. However I am not sure if it is easier to understand though...

The program is in a few files which are to many to post here but listed below is from the main file if this is interesting to you.

const S8 txBuf[] = "Welcome to XC164CS Serial EEPROM reading/writing";
const U16 txSize = (sizeof(txBuf) - 1);
S8 rxBuf[64];

/**/
void main (void) {

  U16 address = 0; /* EEPROM address for string */

  SSC0_Init();  /* initialize the SSC peripheral */
  PSW_IEN = 1;  /* globally enable interrupts */

  /* write bytes to the EEPROM */
  EepromWriteEnable();
  while(EepromBusy());

  /* max page size if 64 bytes in a write */
  EepromWrite(address, (U8*) &txBuf[0], (U16) txSize);
  while(EepromBusy());

  /* wait for WRITE command to complete */
  while((EepromReadStatus() & RDY_) == true);

  /* read back the bytes we wrote to the EEPROM */
  EepromRead(address, &rxBuf[0], (U16) txSize);

  while(1){
    _nop_(); /* loop forever */
  }
}

Hi Chris, my email is iker@leako.com.
Send me please the program that you have and I will create a simple project in uVision with it. I only want to understand EepromWriteEnable, EepromWrite, and EepromRead functions.
Thank you very much Crhis. You are teaching me a lot. ;-)

Hi John,

The Keil project was sent to your email address.

-Chris

Thanks Chris. You are GOD!. Inmediately IÂ'm going to study the proyect and attempt to understand it. I will comment you the results. Give me some time :)

Hi Chris,
I have 3 questions about the project:

First one: I suppose the program writes and reads this array: txBuf[] = "Welcome to XC164CS Serial EEPROM reading/writing" into EEPROM. Isn't it?
How can I check if this program writes and reads correctly?

Second one: How does the "EepromStartTx" function work? It doesnÂ't have any "for" loop to send each byte of txBuf[] to SSC0_TB?

Third one:Is SSC0 interrupt system similar to ASC0?
Thanks. I go on studying.

Other question:
Is there any time to comply with this?

void SSC0_viTx(void) interrupt SSC0TINT
...
        if ((eeprom.cmd == WRITE) && (eeprom.bytesTx == START_TX_MSG))
...

eeprom.bytesTx is going to take as maximum, 2, isn't it?

There are two functions to read/write the serial EEPROM

U8 EepromRead(U16 address, S8 *des, U16 cnt);
U8 EepromWrite(U16 address, S8 *src, U16 cnt);

Each has three parameters, the address, a pointer to first element of data (to read/write) and the number of bytes elements to read or write from the serial EEPROM.

In the example the txbuf[] is a constant string which is written to the serial EEPROM. Again it is an argument so you can write what you want. In this example the SSC0 is assumed to be exclusively used for communication to the serial EEPROM. In addition it also puts the command and address into the data stream that the serial EEPROM sees. The EepromRead routine also strips out the address and command from the data receive stream so the data the application sees is strictly application data (protocol overhead of the serial EEPROM has been removed). In other words the driver is hiding some details from the application which is what I wanted.

How can I check if this program writes and reads correctly?. You read back what you wrote and if they are the same then you were successful. You could also add more checks to make sure that a write actually started by querying the serial EEPROM. Hook up a LSA and look at the SPI data streams...

How does the "EepromStartTx" function work?
It only starts the transmission and the interrupts serve to fill the rest of the data. No for is used as it is interrupt driven in the background.

Is SSC0 interrupt system similar to ASC0? They are similar in that they are both interrupts and relate to a serial protocol. The user's manual explains how they each behave.

Is there any time to comply with this?

Not sure what you mean? The transmit interrupt is working on a pointer from the serial EEPROM driver that changes depending on what count it is on and what mode (read or write).

The driver is sending the command and address which is not it the data string you are passing. The transmit interrupt routine could be made simpler if you want to include the command and address in your data. It depends on what is more important to you, abstraction of your data from the driver or not.

Hi,
I tested the program by using the uVision Debugger in evaluation mode.
I don't understand why the program enters into the receive interrupt while the message array is being written in EEPROM.
I am trying to visualize what I read from EEPROM ("Welcome to XC164CS Serial EEPROM reading/writing")
in hyperterminal through ASC0.
How could I transfer the read data from EEPROM to new array in order to send this array afterwards for ASC0?
How would you do this?
Thanks

In any case, I think that the program doesn't read properly the written data because when it gets EepromRead function, the receive interrupt is executed only once. Correct me if I am wrong.

Chris,
Have you tested this program by using keils ulink2?

I tested it with ULINK and Lauterbach. Everything works as expected.

What hardware are you using? The hardware I used was the Starter kit which uses SSC0 and P3.6 for the chip select.

-Chris