View Full Version : give an address to pic on rs-485 network

- 2nd February 2014, 08:32
I'm trying to figure out how to put an address in pic by Dip Switch. What I mean is I'm trying to teach pic to determine network address 485 by changing the state of dip Switchs.

sample request:
for address 001 - dip switch will be off off off on
for address 002 - dip switch will be off off on on
and so on.

what i am missing is the true table and how to code it in picbasic.

I sure like a snip of code to understand this issue.

Does anyone have an idea?

- 2nd February 2014, 10:30
Lets say you have the four switches connected to PortB.0 thru PortB.3 and that they pull their respecitve pin high when 'on'. Then all you need to is

TRISB = %00001111 ' lower four bits as inputs, rest as outputs
Adress = PortB & 15
At this point the variable Adress will contain the the "value" of the dip switches as coded "in binary" and allows for a total of 16 adresses, 0-15.

In your example, the first line would be adress 1 but the second would be adress 3 when using the above code.


- 8th February 2014, 22:50
Normally rotary BCD selector switches are used.


This save the user having to work out which dip switches to set to get the required binary value.