Hi everybody!
First of all,I would like to thank you Ujjal Kar for building up this site!
After my first PIC controlled Moonflower project i want to develop a scanner with DMX support.
I didnt found any site with DMX description as clear and detailed as yours!Once more:Thank you!
Now after reading the properties of DMX-512 i have some questions to you:
1. I´d like to use PIC16F877 for control.It has an UART but in the datasheet i cant see the 250kbaud rate for 20MHz crystal only for 16MHz.
I´m quiet new at PIC16F877 and UART communication so could you please look into the datasheet and watch for the baud rates to see if i am wrong?
www.datasheetarchive.com

2. What MTBF and MTBP times are used at commercial DMX controller desks for lighting equipments?Because i would like to know if my scanner will be controllable by them.
or firmwares are written the way that no matter what timing is used the fixture will understand the controller(from another manufacturer too)?
The KEY is always more than xx microsecs at each timing and the receivers important job is to watch out for the line levels?
3. How do the controller knows how many frames needs to be sent and when to close the packet(send MTBP)?Or it goes through 512 channels?

4. What will happen if i start the addressing from Ch13? Ch1-12 will loaded with 00h?

5. How to construct the circuit to connect controller to fixture? for example: CPU#1-->SN75176#1-->cable-->SN75176#2-->CPU#2 ???
Or do i need optocouplers or something else? What to do with SN75176s output if the cables are disconnected(can float?)?

6. I have to write the program the most optimal way so code processing fits between DMX timing intervals?
If i write a long code that doesnt fit the timing then can i get wrong values or confusion?
Or it can be bypassed if i use Timer modules of PIC and interrupts?

7. Your page is about DMX512 and not about DMX512-A,am i right?Do newer fixtures use this newest version?

8. The fixtures are connected the way that cable from ones output goes to the seconds input and this input is connected with its output by wires?
(sorry but do not know about daisy-chain)

I apologize for the lots of questions and for(maybe) the stupid ones!
If you answer any of them please indicate question number too!

Thanks!