PIC 101b (rs232 hardware)

[xxalexx at ix.netcom.com]

rs232 hardware
#1
This example will use a psuedo inverted rs232.
You will need a DB  9 pin serial female connector.
These are avalable at Rad. Shack. get the one with terminals
and solder lugs installed, or you can cut a old serial mouse 
or buy a rs232 cable and cut it. 3 feet should work for the
bench top.  The majority of connectors will have pin numbers
on them. Looking at top of female row there will be 5 holes
with numbers from left to right of 5 4 3 2 1
5=grd
3= recieve from PC
2=transmit to PC
Solder 22 gauge solid wires to these pins or  if using a cut 
cable locate the wires with a ohm meter and solder some short lengths
of 22 gauge solid wire.
On the end of the pin 3 wire solder a 1/4 watt 33K resistor.  

#2
Connect rs232 pin 5 wire to col. X grd on proto board.

Connect rs232 pin 3 (the other end of 33K resistor) to  B1 on proto 
board = PIC  pin 18 recieve.

Connect rs232 pin 2 wire to  B2 on proto board = PIC  pin 17 transmit 

#3
Remove PIC chip if installed
Check circuit by plugging rs232 coonector into your PC serial port, 
and turn on. Take voltmeter (a short piece of solid wire attached to 
alligator clip and probe leads is helpful) and plug grd. into col X
voltage at B1 pin18  recieve should = between -12 and -10 volts.
voltage at B2 pin17 transmit  should = around 0 volts.
 
Summary:
Your proto board should now have a 7805 5 volt regulator with
5 volts going toPIC  pin 14 (power) and PIC pin 4 (reset)
PIC Pin 5 to grd. 

A 4 MHz cyrstal at PIC pin 15 and 16 with two  corresponding 27pf 
capcitors to grd.

A rs232 9pin connector with  rs232 pin 5 to grd. 
rs232 pin 3 with a series 33K ohm resistor to PIC pin 18
rs232 pin 2 to PIC pin 17.