Has anyone used the AT24C512B? Any issues?
Or, suggest another 512K EEPROM with I2C? (3.3v)
--- In m..., "Louise Chan, Jr." wrote:
>
> Hi,
>
> I have limited experience in using the TI MSP430 mcus for embedded
> development so I'm hoping that anybody here who has plenty of
> experience with this mcu particularly using it with the new line of
> ATMEL I2C EEPROMs (AT24CxxxB) would be able to help me with my problem.
>
> I've created code to access the ATMEL AT24C512 EEPROM (this is the
> older version of the 64kb Atmel I2C eeprom which is now obsolete)
> using the I2C peripheral of the MSP430F1611 mcu and had no problems
> with writing and reading data to and from the EEPROM.
>
> A few months after developing the software for the MSP430F1611, I got
> hold of the news that ATMEL has replaced the old AT24C512 eeproms with
> the newer AT24C512B eeproms from which I gather operates at a faster
> clock at lower voltages (@ 1.8V operating voltage, it can accept data
> transfer speeds of up to 400khz). The older version can only operate
> up to 100khz at 1.8V operating voltage.
>
> The I2C driver code that I've created for the older version of the
> ATMEL 64kb I2C eeprom operates with an SCL = 80khz (approximately)
> using the following settings in the I2C peripheral:
>
> SMCLK = 5.5Mhz
> I2CPSC = 2
> I2CSCLH = 9
> I2CSCLL = 9
>
> I'm not using interrupts when sending or receiving data to or from the
> EEPROM. Instead, I'm using the polling method wherein I just read the
> status of the I2CIFG interrupt flags to see if I've completed an I2C
> send or receive operation.
>
> The problem that I'm experiencing right now with the newer ATMEL
> AT24C512B eeprom is that my existing code suddenly won't work. I
> always keep on reading 0's everytime I access the EEPROM using the
> existing code. I've experienced once or twice where I can read data
> correctly but most of the time, I keep on reading zeroes from the new
> EEPROM part.
>
> I've tried changing the SCL clock to a faster rate (approx. 300khz)
> and even tried changing the pull-up resistors on the SDA and SCL lines
> just to make sure that the rise time of the SCL and SDA signals would
> improve but I still am not able to make my I2C code work with the new
> Atmel EEPROM.
>
> Has anybody here experienced the same problem with the new ATMEL I2C
> eeprom parts and have come up with a fix?
>
> Appreciate any help that I can get.
>
> Thanks.
>
> Best regards,
> Louise
>
