How long?

Sniper King

From power on to program execution how long does it take?

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·- Ouch, thats not suppose to be hot!··


Michael King
Application Engineer
R&D
Digital Technology Group

Sniper King

This is what I am trying to do.· It is simple really.

I have a parallax PIR sensor.· I have it set to go high on detection.·The PIR sensor will stay high for 2 seconds.·I have this switching power on to the propeller.· That works.· The code in the propeller is small...really small for testing...·

DIRa[noparse][[/noparse]15]~~
repeat
 OUTa[noparse][[/noparse]15]:=1
 

pin 15 also drives the switch.· So in essense the PIR sensor activates, switch goes on. Propeller starts program execution and keeps the switch alive until it finishes what it needs to do and then will commits suicide by driving pin 15 low( in the finished software).

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·- Ouch, thats not suppose to be hot!··


Michael King
Application Engineer
R&D
Digital Technology Group

Paul Baker

That information is in the datasheet in section 9.6, there is no exact time provided because the boot sequence uses the internal RC clock which varies in it's speed across chips because of process variation.

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

Sniper King

if I have 2 seconds of power, is that going to be enough time for the program to execute?

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·- Ouch, thats not suppose to be hot!··


Michael King
Application Engineer
R&D
Digital Technology Group

Mike Green

The time is on the order of 1.5 seconds (see page 29 of the Datasheet). You would do much much better by keeping the Propeller powered up, but running at a slow clock rate (like using the internal RCSLOW clock) and using the WAITPEQ/WAITPNE statements to look for the PIR output to go high. The WAITPEQ/WAITPNE instructions markedly reduce the power consumption of the cog and the other, stopped, cogs take very little power. With the crystal oscillator and PLL turned off, the idle current of the Propeller is well under 100uA, probably closer to 50uA. You can go through the graphs in the Propeller Datasheet to figure out the specifics for your situation.

Sniper King

Can you give me a little code to know what direction to go?· At some point I need to go to a higher clock speed to run fullDuplexSerial than then go to a low power mode again.

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·- Ouch, thats not suppose to be hot!··


Michael King
Application Engineer
R&D
Digital Technology Group

Sniper King

{{
PIR UDA Sensor.spin, v1.1,Michael King
┌──────────────────────────────────────────┐
│ Copyright (c) 2008 Michael S. King       │               
│ See end of file for terms of use.        │      
└──────────────────────────────────────────┘

 
}}
CON
_clkmode = xtal1 + pll16x
_xinfreq = 5_000_000
VAR
 
OBJ
       
        Send : "FullDuplexSerial"
        
PUB main
DIRa[noparse][[/noparse]15]~~    
OUTa[noparse][[/noparse]15]:=1  ' Keep Power alive after PIR out goes low     
 
  
 
 dira[noparse][[/noparse]16]:=1 

 outa[noparse][[/noparse]16]:=1  'PIN High of PWR to switch XTEND module on 

 send.start(21,17,0,9600)  ' start FullDuplexSerial

 waitcnt(10_000_000+cnt)   'Wait a bit for the XTEND to be ready

 send.str(string("<*00000001*S*>")) 'Send activation of sensor Message

 waitcnt(30_000_000+cnt)  ' Wait for message to be sent

 outa[noparse][[/noparse]15]:=1     ' Kill thy self
 
 

This is my code..· I dont know how to use the RCSLOW or the WAITPEQ commands properly.· That certainly sound like the way I want to go though!· Makes this really simple to implement.· But how do I get the clock speed up for the use of the FullDuplexSerial Object and then bring everything back to RCSLOW clock again.

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·- Ouch, thats not suppose to be hot!··


Michael King
Application Engineer
R&D
Digital Technology Group