One Shot Toggle and Repeat

Rob7

Hi all,

O.K.
I now have all the hardware I need for my next project.
I am trying to toggle 4 pins (Output) set to read an input, at 5 vdc each pin. (I haven't forgot the input resistor.)
Read pin x, if high, toggle pin output x, repeat for that pin if input is high.
4 input pins
4 output pins
All 4 input must be read in parellel.
I have run thru the tutorial, I just can't seem to get it !
I must be brain damaged...
Help!!!!!!!
Can someone please show me the correct way to start the program.·I think with this help I can add more pins later and modify them to my applications.

Rob7

Mike Green

Does this do what you want?

PRI project | temp
  temp := ina[noparse][[/noparse]4..7]      ' reads pins 4..7 at the same time
  outa[noparse][[/noparse]0..3] ^= temp  ' exclusive or's (toggles) corresponding 0..3 pins that were high

Rob7

Thanks, Mike

I changed PRI to PUB to get it to load.

I cannot seem to get an high output from the inputs ?



Rob7

Mike Green

Rob,
This was only a code fragment to illustrate something. I assumed that you've already set up the pins for input or output and that the input pins were 4 through 7 while the output pins were 0 through 3. The routine only reads the input pins once and toggles (or doesn't toggle) the output pins once. You have to call the routine each time or put it in a repeat loop. If an input pin is high, the corresponding output pin will be toggled every time the routine is called. Is that what you want? Maybe you need to give more information about what you're trying to accomplish, perhaps with a schematic drawing.
Mike

Rob7

Thanks, Mike.

Sorry for the confusion.

The outputs work , I am having trouble with creating inputs to trigger the outputs.

I have attached the outputtest. spin program.

Here are the schematics for my input and output pcb's.

Rob 7

Mike Green

The 74LS14 is a TTL device and, as such, has a high output voltage of around 3.4 with a minimum of 2.7. The Propeller has a switch point of about 1/2 Vdd so this should be enough. Your input circuitry seems like overkill. The Propeller doesn't need an inverter. Would it work just to use the phototransistor to pull down the signal line with a resistor to Vdd (3.3V)? You could put the resistor on the Propeller end of the connector where there's 3.3V available. On the output end you could do something similar with the Propeller switching the other end of the LED to Vdd and the LED cathode grounded through an appropriate resistor.

If you're going to use your existing circuitry, do check the output high and low levels with a voltmeter to be sure the voltage margins are adequate for the 3.3V CMOS inputs.

Rob7

Yes, Mike.

Overkill is right, However these boards were designed for another purpose. I can change the input resistance with the jumper resistor abd buffer all noise at the inputs.

Rob7

Mike Green

It should work. I'd check the voltage levels, then try it with the Propeller one input at a time with an LED (and resistor) on a Propeller I/O pin and use a simple program to just copy the value of the input pin to the output like:

  repeat
    outa[noparse][[/noparse]outpin] := ina[noparse][[/noparse]inpin]

Then fiddle with the isolated input to see if the Propeller sees the proper signal level.

Rob7

Cool,

I will try it tonight !

Thanks Mike for all your help !



Rob7

Phil Pilgrim (PhiPi)

The inverter you use is a Schmitt trigger, so it might not be such a bad thing to leave in there. OTOH, if you were to use an H11L1 optocoupler, it has the Schmitt trigger built in, and you could get rid of all that external circuitry. Where you might be getting into trouble is the two LEDs in series on the input circuit. Just make sure your input signal is substantially higher than the sum of their two forward voltages. Also, since the outputs of your optocouplers are connected in a Darlington arrangment, they're not going to switch very fast. If your inputs are toggling back and forth quickly, the transistor circuit won't be able to keep up, and you won't see any transitions on the output. The H11L1 will solve that problem nicely.

-Phil

Rob7

O.K.
I have two short programs and they work seperate. I am trying to combine them to creat a pulsout program but I am having problems.
At the Outa := Pulsout I want to look down and run the pulseout string, but however I try. I cannot get it to work. Can someone please head me in the right direction.
Here is the combined program.

Thanks!

Rob7

Beau Schwabe

Change your "repeat" loop to look something like...

 Repeat                                'Infinite loop
' 
   If Ina[noparse][[/noparse]0] == High                   'If pin is high
      Pulsout_uS(4,1000)               '   Pulsout
   Else
      Ina[noparse][[/noparse]4] := Low

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Beau Schwabe

IC Layout Engineer
Parallax, Inc.

Mike Green

There's a comment that you're setting pin 0 to be an input, but the statement says "Dira := In". It shouldn't make any difference since all pins are input after a reset unless changed otherwise. What is "Outa := Pulsout" supposed to mean?
If you want to call the routine from the BS2 object, you need a function call. Look at the comment in the routine for an example.
Since you've incorporated the routine into your own program, the "BS2." is not used. A statement like "PULSOUT_uS(4,500)" will
produce a 500us pulse. There is no such statement as "Low := Low". If you want pin 4 to become low, use "OUTA := Low".

It looks like you're trying to use statements from PBasic on the Propeller. The Propeller is very different, but not hard to understand. On the Stamp, in addition to statements like LOW and HIGH, you can directly access the direction register and the input and output registers as if they were 16 bit words. On the Propeller, that's all there is. You have to do it that way.

The BS2 object was written to help people make the transition from PBasic to SPIN by providing similar functionality, but they're
not exact replacements. The routines have to be called with a SPIN function call (which is a statement too) and sometimes several routines have to be called to do what one statement in PBasic will do (like SERIN or SEROUT) because these operations are not built-in.

Rob7

I see,

Thanks Mike, for clearing that up for me.



Rob7