hi all I am doing a project which involves storage of some values in nonvolatile ram so in case of powerdown the value remains there and it can be read back when circuit gets power.This value should be modified also. I am using atmel 89C51 and i am using atmel's 24C04 as nonvolatile ram. I have done my coding in assembly. Now my problem is I dont know how to read data from n write data to this ram.
Hi, Have you tried Ateml's website to see if they have anything you can use? Mark.
AT24Cxx Serial EEPROMs have 2-wire I2C interface. This is not good choice for AT89C51 to communicate with such way due you should write software emulated I2C protocol. I suggest you either select MCU with hardware I2C interface (like AT89C51IC2, ID2) or select another type of serial EEPROM. For example, AT25xx serie works via SPI link. This inteface is much more easy to be software emulated. There are alot of C51 MCUs which have hardware SPI, for example, AT89S53, AT89S8252, S8253 etc. Moreover, in some cases SPI may be obtained with UART in mode 0. Anyway, here is the links: How to connect AT24 to C51 - http://www.atmel.com/dyn/resources/prod_documents/doc0507.pdf How to connect AT25 to C51 - http://www.atmel.com/dyn/resources/prod_documents/doc0628.pdf By the way, AT89C51 is not produced anymore, use AT89S51 instead, see here: http://www.atmel.com/dyn/products/devices.asp?Status=Mature&family_id=604&family_name=8051%20Architecture Regards, Oleg
hi i need to save data from micro to 24c02 and read data from 24c02 to micro please guide me about way. thanks
i need to save data from micro to 24c02 which micro? (derivative - not a generi9c name) Erik
Hi, http://www.atmel.com/dyn/products/product_card.asp?family_id=647&family_name=Serial+EEPROM&part_id=2477 should take you to a page where you can see the following Interfacing AT24CXX Serial EEPROMs with AT89CX051 MCU and if you d/l the pdf and example code then that should allow you to implement 'bit bashing' routines on a micro with no native I2C support. I've implemented a master/slave I2C using the atmel code and it isnt difficult to tailor it to your specific need (ie. which port PINS to represent SDA/SCL) especially with the amount of info avalable even within just the atmel website. But if you are still having problems, if you havent already, search the 'keil discussion forum' as I2C is quite a popular subject and Im sure other people have provided links to other resources that may help you. Hope this help. Mark.