Assembly pushbutton?

electric550

Hello can somebody post some assembly code to mirror a pushbutton to an LED(Pushbutton positive when pressed)? Or even better seven pushbuttons to seven leds and record the lengths of the button presses to variables? I was thinking maybe using the counters or something but I am just starting in parallax assembly and really need to learn how to use the IO more efficiently. Is there a way to address single pins in assembly? I am surprised that all I have found for pin IO requires bit masking the entire port. I have been using assembly for phillips and si labs chips, (in which case I know how to do this), but it seems complicated to me right now on the propeller. Anyways thanks for your help.

TreeLab

I would recommend that you first code it up in spin, which shouldn't take more than 1/2 hour. Then if you need the speed advantage, redo it in PASM (or C). My guess is that spin will be more than fast enough for you. Get the logic right, then move it to pasm.

You should also consider the needs of software/hardware debouncing of the signal. Usually this introduces enough of a delay that the timing becomes spin compatible anyway. Search the forum, there have been some threads recently on this.

Cheers!
Paul Rowntree

TJHJ

Short summation this is what you will need.
Asm has no individual bit adressing, so you must use masks.
To set a pin use
or REGISTER, Mask
To clear a pin use

andn REGISTER, Mask

EDIT : Hey it works. Here is the full version

Con
_clkmode = xtal1 + pll16x
_xinfreq = 5_000_000
InputPinNum = 0
LedPinNumber = 1
Var
Long AsmVar
 
 
Pub Run
Cognew(@Start, @AsmVar)
repeat 'Repeat forever
Dat
org
 
Start
  andn DIRA, InputMask ' Make sure InputPin is an input
  Or   DIRA, LedPinMask   ' Set led to output
  andn OUTA, LedPinMask   ' Make output Low
 
 
Main
  mov  State, INA     'Get the current pin state set
  shr  State, inputPin  wc ' Move it to the right to place in D[noparse][[/noparse]0] and write in C flag field. 
 
 if_c or OUTA, LedPinMask ' If input == 1 then c flag was set so make ledpin high
if_nc andn OUTA, LedPinMask' Turn off the pin if input == 0
      jmp #main             'Jump back and do it all over again
 
 
InputPin long InputPinNum 
InputMask Long  |< InputPinNum
LedPinMask Long  |< LedPinNumber
 
 
state res 1 'A long for state of input

This should get you·started on the right track.

TJ

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I owe everyone here a bunch, So thanks again for answering my dumb questions.
Projects. RG500 ECU system. PropCopter. Prop CanSat. Prop Paste Gun.
Suzuki RG500 in a RGV 250 frame.
Bimota V-Due (Running on the fuel injection system)
Aprilia RS250

Post Edited (TJHJ) : 4/9/2009 4:36:16 PM GMT

electric550

This assembly is much more roundabout than the assembly I am used to. Thanks for the help.