not sure if this what you want but if i am reading this correctly the code might be the following ,

Assumptions that is taken for the following example code are

1.digital ports have been set in config not analog
2. the OSC type is defined in config correct value , assumed to be 8Mhz in example ,
3. the port is setup for output in config eg TRISB = %00111100
4. the port used is able to be output not input only
5. correct setting of week pullups is set
6. the output pulse is expected to be a digital output not varable analog
7. other external ccts not effect current drain on output etc
8, that other code required in pic will not stop the loop

This code only creates a square wave pulse of 10Ms high and 10ms low during its continued execution ,and thats fine as long as thats all its going to do and no other program needs to be called else it will stop

to make it clearer and to get what you end up wanting it would help if you advised the chip type ,and associated ccts and what the end goal is

but given these assumptions above

Code:
  DEFINE OSC 8             ' Timing referance for pause , pauseus commands
 H9 var PORTB.0            ' Port B.0 is output pin digital TTL 

H9 = 0                           ' Set output to low on startup

Main:
H9 =1             ' Set output to high 
pause 10         ' allow it to be high for 10ms 
H9=0              ' set output to low 
pause 10        ' allow pulse low for 10ms
goto main
regards

Sheldon