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Memory expansion info and KEIL support

andre moutinho

Hi,

I have to improve a system memory capability
with the minimum IO usage possible. I am thinking to use I2C memory device which spends 2 I/O pins. There's also SPI devices which need 4 I/O pins. It will be very usefull if anyone could help with the following information:

1) Some I2C and SPI available vendors. Some vendors URL will be very usefull.

2) Does KEIL have I2C and/or SPI facility support ? Do I have to implement whole potocol by hand ? Does anyone have any example code using such memories ?

3) How can I connect I2C and SPI device to the AT89S8252 IO pins ? Which pins can I use ? Any pin ?

4) What is the difference between SPI and I2C memory devices ? Which one is cheaper ? What are the good and bad features of them ?

Any information on any of these topics will be very appreciated.

Thanks a lot,

Regards,

Andre

  • 0

    1) Some I2C and SPI available vendors. Some vendors URL will be very usefull.
    philips, st micro, microchip
    Use Google for URL

    3) How can I connect I2C and SPI device to the AT89S8252 IO pins ? Which pins can I use ? Any pin ? yes

    4) What is the difference between SPI and I2C memory devices ? Which one is cheaper ?
    about the same
    What are the good and bad features of them ?
    some like the mother, some like the daughter, a matter of taste.

  • 0 in reply to erik malund

    You find on my side a I²C simulation for different devices (http://www.c51.de/c51.de/Dateien/uVision2DLLs.php3?Spr=EN).
    You find also C-Code for the I²C slave protocol.

    Michael

  • 0

    Questions 1-3:

    Look on the support section of this site, or the free CD - both full of links to Vendors' sites, articles, appnotes, etc, etc,...

    Look in the code examples, too - there's loads.


    "4) What is the difference between SPI and I2C memory devices?..."

    Probably the only difference is that one has an SPI interface, while the other has an I2C interface; internally, I expect, the actual memory of the device will be identical.

    For the differences between the interfaces, go to http://www.lvr.com/ and search for "microwire" - there's an article which compares & contrasts SPI, Microwire and I2C.