suppose if i want to design a circuit which will glow in night time and will off in day time.... how to write a vhdl program for the real time clock that connects my problem

Why don't you use a simple 8-bit uC to do that?

Why, indeed. But being this a hdl oriented forum, this seems to be a simple little project, useful to learn bits and bolts.

One possible approach would be to implement the application with a toplevel state machine, and an interface block with the RTC chip. Assuming that you have an external RTC chip (as mentioned), this block would communicate with it (SPI master / I2C master), get the time of day registers, and set an internal register with the time. The top level state machine could use the time as a condition to change states.

An slightly different approach is to build the whole RTC circuit in the fpga, from the system time base.

- Jonny

hmm johny,,, thats a goood idea ,, so how to connect rtc with the program..could you pease explain me in detail

What program? There wouldn't be any program to connect with.
Do you realise that vhdl code describes hardware structures, instead of a software program, don't you?

I suggest you to read on sequencers and state machines. Control logic that execute functions like the one you described can be implemented using a state machine.
The RTC chip (are you using a RTC chip?) interfacing with your circuit will depend on the RTC chip. There are I2C, SPI and One-Wire interfaces to RTC chips.

You will have to elaborate on your question.

- Jonny

Hi all,

I am a beginner in this study area.
And I have some fundamental questions needed someone to give me some suggestions.
I want to use xilinx EDK to design an architecture using 2D_BinDCT. So I need to create a hardware platform with XPS then I should add a new 2D_BinDCT module. But the first time I tried to do the code of 2D_BinDCT .vhd ( xilinx ISE) , i can't finish it because i need the transposition matrix part . A small request , any one can help me or give me some suggestions for how to do this part or give me some decomentation or examples to refer.
Thanks in advance for your suggestions.

please give me vhdl code for modified booth & UART?

I am using rtc ds1307 and spi module. Can you explain me about the coding.

P.s - m a beginner in vhdl.

Hi, if you are a beginner, it is more simple to learn about basic combinatorial and about state machine.
Start just assign a value to pin, then learn something more...
Try this : http://www.fpga4fun.com/
or http://www.pyroelectro.com/edu/fpga/introduction/

When you got some basic skill on VHDL coding you can learn about how to integrate IP core like SPI or I2C to read write your device.
Is also possible and not so difficult to code a real time clock on VHDL, I think is an exrcise of no more than the time to wrote in. This in case you know how to manage counter and state machines.
Your question has too too many leak to be of any little help.
Best regards
Roberto