I2C comm. from STR712 to M24C32

[alexandermueller9]

Posted on July 28, 2006 at 06:09

I2C comm. from STR712 to M24C32

[alexandermueller9]

Posted on July 19, 2006 at 08:55

Hello I am working on a byte read routine.

I want to read a single byte from the EEprom.

I found this information in the datasheet for M24C32-:

''... The bus master must not acknowledge the byte, and terminates the transfer with a Stop condition.''

One of the examples of found her in the forum ''Byte read from the external I2C EEPROM mounted on the STR710 demo board'' has a function EEPROM_byte_read:

/* Send the EEPROM address with LSB bit set */

I2C_AddressSend (I2C0, M24C08_Block0ADDRESS, I2C_Mode7, I2C_RX);

while (I2C_FlagStatus (I2C0, DIRECT, I2C_ENDAD)==RESET);

I2C_FlagClear (I2C0, I2C_ENDAD);

/*Read 'Buffer_Size' bytes from the EEPROM starting from address 0x00 of Block0

and place them in Rx_Data[] array */

/* Generate STOP condition */

I2C_STOPGenerate (I2C0, ENABLE);

/* Read byte */

I2C_Rx_byte = I2C_ByteReceive(I2C0);

I would have expected something like I2C_AcknowledgeConfig. Other examples, that read more bytes had special cases for the second last byte and the last byte to receive.

Did I get something wrong?

[alexandermueller9]

Posted on July 19, 2006 at 09:39

I have changed the receive function:

TEepromData EepromByteRead(u16 address)

{

TEepromData data;

u8 buffer[2];

I2C_Tx_Status status;

u8 dummy;

//Generate Start

I2C_FlagClear (I2C1, I2C_ENDAD);

I2C_STARTGenerate(I2C1, ENABLE);

while (I2C_FlagStatus (I2C1,DIRECT,I2C_SB)==RESET);

//Transmit the address as write mode

I2C_AddressSend (I2C1,EEPROM_ADDR,I2C_Mode7,I2C_TX);

//Test the end of address transmission

while (I2C_FlagStatus (I2C1,DIRECT,I2C_ENDAD)==RESET);

I2C_FlagClear (I2C1, I2C_ENDAD);

//Transmit the address de memory

buffer[0] = address >> 8;

buffer[1] = address & 0xFF;

status = I2C_BufferSend (I2C1, buffer,2);

//Generate Start

I2C_STARTGenerate(I2C1, ENABLE);

while (I2C_FlagStatus (I2C1,DIRECT,I2C_SB )==RESET);

//Transmit the address as read mode

I2C_AddressSend (I2C1,EEPROM_ADDR,I2C_Mode7,I2C_RX);

//Test the end of address transmission

while (I2C_FlagStatus (I2C1,DIRECT,I2C_ENDAD)==RESET);

I2C_FlagClear (I2C1, I2C_ENDAD);

//Receive the data

I2C_AcknowledgeConfig (I2C1, DISABLE);

data = I2C_ByteReceive (I2C1);

//Generate Stop

I2C_STOPGenerate (I2C1, ENABLE);

I2C_AcknowledgeConfig (I2C1, ENABLE);

return data;

}

To the the function I have used this code:

u8 i;

i=0;

while(i

EepromByteRead(i);

EepromByteRead gets stuck somewhere while looping.

Sometimes I can read several bytes before it locks up,

sometimes it locks up on the first loop.

Locking up means the code ist stuck in the ''Generate start'' while loop:

//Generate Start

I2C_FlagClear (I2C1, I2C_ENDAD);

I2C_STARTGenerate(I2C1, ENABLE);

while (I2C_FlagStatus (I2C1,DIRECT,I2C_SB)==RESET);

This has happened before (before I added the I2C_AcknowledgeConfig lines).

Maybe we have to wait for a flag after generating STOP?

Alexander Mueller

littleBLUE GmbH

[graziano]

Posted on July 28, 2006 at 06:09

I'm tryin to communicate with a TI DA5571 dac, but my application got stuck in the instruction

while (I2C_FlagStatus (I2C1,DIRECT,I2C_ENDAD)==RESET);

I can't see nor the clock neither the address address data out of the micro pins.

Any suggestions ?

thanks in advance

GM