Hi there...its not something i have to hand in....its a project i am doing for myself....but the thing is i have no basis whatsoever in electrical engineering...i am more a program...its more urgent time wise because i only have a week off from work to actually work on this. Here are the questions that have been really bothering me...i appreciate your help.
So here are my questions:
Regarding both documents:
1. Zero crossing detector section:
a.It says that the RBO pin of the pic will be changed from Vss-0.6V. Is this a set value due to the diodes or is there a way of calculating this value?
b.Input threshold will be 0.8Vdd or o.2Vdd. Why? Where do you get the values 0.8 and 0.2 from?
2.What modifications would you make on all these circuits for an Ac of 230v at 50Hz. Especially diagrams 3 of 5 and 5 of 5 from the AN236 document.
3.Please explain how diagram 4 of 5 functions.
4.Diagram 5 of 5: How would you modify it for 230V @50Hz. Please explain this circuit to me. Also power in refers to the the AC input to the the transmitter and receiver respectively. But what is the POWER OUT point?? What is it used for?
5.You would obviously require two different power supplies, right? Because both the transmitter and receiver need to be connected over the AC lines for communication.
Regarding the second document –not AN236!!!!!
1. Can you make out what type of LCD display is used here?
2. Look at figure 1 under the receiver section:
a. The Ac mains are connected directly to the voltage limiter. How?
b. There are pins on the PIC microcontroller that are connected to relays. Why???
3. SOFTWARE SECTION
a. Algorithm for transmitter: STEP 3 says to configure RB1-RB4 as input ports – this would be for the switches, right?
BUT
The Algorith for the receiver: STEP 1: sets RBO-RB4 as output-why???
Are they using two separate PICS for this project??
b. LOOK at the Flow Charts: On all the flow charts there is a circle with an R in it.
What is this????
Thanks a lot for all the help....really really appreciate it