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serial memory interfacing with 89s52?

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siprax345

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hi...i want help in interfacing serial memory with 89s52..how to make hardware in this case and also any software intialization is required..can you help me..any web link for this????
 
Serial EEPROM memories is what I think the poster is talking about. Unfortunatly there are several different interface methods. Give us the part number of a serial EEPROM and we will be better able to help you.

In most cases it is just a matter of connecting two or more port pins to the meory chip without any additional glue logic. Then the fun begins because you get to bit-bang the data in and out. It just doesn't get any better than this! Ahhhh......
 
query regarding interfacing memory to 89S52 and 80C552

hello,
for interfacing serial mem to 89S52 do we need to follow a master salve methodology ie do we need burn the code for accessing the mem in the on chip rom and the main code in the mem , what shuld we do if donot have the on chip rom.
Is there any way that controller directly starts accesing serial mem when ea bar is grounded ?

also we req. some guidance in interfacing 27C512 Eprom to 80C552 microcontroller from philips.
The hardware we have traced many times but we doubt whether the controller is able to fetch the code from 27c512. in the system we also have a RAM (11 bit address bus) and there is no deocding logic
 
spirax345

Without looking at a schematic I can only guess at what you are working with. Serial EEPROMs are not intended to contain instructions which the processor executes directly. In order to use a serial EEPROM for non-volitile data storage you need to have some code in the 80C552's code space.

A 27C512 contains 64K bytes of memory space. This is all the code space the 8051 architecture allows. If this is an existing, working design, then I expect that the 27C512's chip select is grounded, and it's OE-bar is connected to PSEN-bar. PSEN stands for Program Store Enable. PSEN is active for ALL instruction fetchs from External Memory, AND for all data READS using the MOVC instruction. The MOVC instruction can only READ from External Memory, it cannot write.

The RAM on the other hand connects to the very same address and data lines as the 27C512. Its chip select is also permanently grounded. BUT its OE-bar is connect to RD-bar(Port 3.7) and its WE-bar is connected to WE-bar(Port 3.6). These two Port 3 signals are active for all DATA READS and DATA WRITES using the instruction MOVX. The MOVX instruction can read and write to a completely different address space than the one occupied by the instructions.

Hope this helps
 
innterface 24c04 with 8051

i want assembly code fir this.use example with simply on/off switch and a led.when push switch the led gose on & when push again led go"s off.24c04 remember that led position.plz...anser this.....thanks
 
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