how to interfac 8051 with 24c256

[jamshaid]

hello
i am new with micro controllers i have this circuit that is using 8051 mc with 24c256 interfaced with it and it operates 7 relays with different timings on and off so fast can any one help me with source code for it
regards

 

[FoxyRick]

Can you post the schematic of the circuit? It sounds like something commercial.

 

[jamshaid]

i don't have its schematic not a professional i have its pcb design file i can send you that if u send me your email address
and thankyou for your reply
regards

 

[FoxyRick]

Please don't send me PMs. You can post the design here, if it isn't a copyrighted design.

I do not see how anyone can write the code for your device though, without knowing exactly what it should do.

Where did you obtain the PCB file?

 

[jamshaid]

i made it myself reversed engineered a already designed board
i have its schematic also but it is not a professional type
i hope you can understand it becase i am no a professional

 

[FoxyRick]

That's a straightforward circuit, at first glance. As I said, it looks something commercial. The circuit is not the issue though; the code is.

I take it that you are not able to write the code yourself; are you trying to fully duplicate the circuit's function? Why?

There is no way that anyone could write code for you to do that, even if they felt motivated to do so. I certainly don't. Without the full programming specifications for the whole device, or full access to the device for testing (reverse engineering), it is pointless to even contemplate.

 

[FvM]

That's a straightforward circuit, at first glance.

I basically agree. The 100 µF capacitors in parallel to the relays look weird and are at risk to cause a power supply breakdown with processor reset or driver transistor damage on switch on. They don't seem to make sense at all.

 

[jamshaid]

i actually have a hex file for that i had made this circuit and its fully functioning with the desired machine but i need a template of how this types of code are written for micro controller to read from 24c256 so i can practice on it and make my own program alter a bit acording to my own needs i am not asking anyone to write a full code for that

thank you for the advise regarding capacitors they were used in original circuit so i kept it that way i will remove it in my new design version

 

[FoxyRick]

The FM24C256 is a FRAM, a non-volatile type of RAM. It uses an extended I2C interface standard. You can view its datasheet and study the protocol here: http://www.ramtron.com/files/datasheets/FM24C256_ds.pdf

Since the AT89C51 does not have a native I2C interface, the first thing that is needed is software I2C code (aka bit-banging). The existing code will implement that on pins P16 and P17 (P3.6 and P3.7). The pin choice is arbitrary. Once a working I2C interface is coded, then that code is used to send commands and read data from the FRAM according to the standard protocol in the datasheet.

Also, take a look at these, they might help:

http://www.atmel.com/Images/doc0507.pdf
https://www.edaboard.com/threads/43804/

 

[FvM]

The FM24C256 is a FRAM, a non-volatile type of RAM. It uses an extended I2C interface standard.

Yes. With a software I2C implementation on a standard 8051, you'll hardly achieve more than 100 kHz bus speed, so you can effectively ignore the extended stuff.

 

[jamshaid]

is there any way i can use another micro controller in the circuit that can choose b/w the 10 24c256 using keyboard interface and an LCD?