AT45 memory

[Pedro Santos]

Hello,

In my projects i use 24C512 I2c eeprom chip but now i need more memory
space capacity and look to the AT45 devices
Have anyone experience with this chips?
Are the read speed higher than the i2C chips?
Sample code available?

Thanks in advance

Regards

Pedro

[SteveB]

It depends on if were talking hardware or software, and what the clock speed of you PIC is. Generally speaking, hardware SPI would certainly be quicker than the software implemented I2C. The AT45's will operate with a very fast clock rate, so the limiting factor will likely be the PIC.

BTW, I have used the 32M version in a datalogger and was quite happy with the results.

HTH Steve

[Pedro Santos]

Hello Steve

I can use the hardware or the software SPI, have You a sample code that i can learn for that?

Thank You
Regards
Pedro

[SteveB]

...have You a sample code that i can learn for that?

Yes...and no. Yesterday my primary computer went on the fritz (I'm using a spare right now), but the data is backed up and intact. It may take a while to get to the info, and it is low on my "to-do" list. But, it wasn't too difficult as I recall. The tricky part, as I recall, was getting the right PBP SHIFTIN/SHIFTOUT mode (I used software SPI). Also, a thorough read of the datasheet is required. I especially liked the buffer feature of the Dataflash I used, otherwise I would have had to use large arrays on the PIC to hold all the data prior to writing to flash. If I wasn't already using the hardware I2C, I would probably would have used hardware SPI.

Steve

[Andre_Pretorius]

hi there
I am looking to interface a at45 data chip to my pic, the problem is the voltages, i need to run the pic at 5V to be able to run at 20mHz but the memory only run on a max of 3.3v can anybody help me with advice:confused:

[mackrackit]

Maybe two power supplies???

[SteveB]

The AT45 is 5V tolerant on it's serial comm pins. I can't remeber about the supply voltage, so you would have to check the data sheet. I have run them off a LDO small 3.3 volt Voltage regulator.
Going from memory, the serial comm pins are pulled up, so the 5v will work with the PIC as well.
It should all be in the data sheet. ;)
Steve