Surviving 1 second without battery power

[Acetronics2]

Hi, Peu

You're out ...

'@ device pic12f683,INTRC_OSC_NOCLKOUT , wdt_on, mclr_off, protect_off, bod_on

 @    __config _INTRC_OSC_NOCLKOUT & _PWRTE_ON & _WDT_ON &_BOD_ON & _MCLRE_OFF & _CP_OFF
 
 
OSCCON = %01100110
CMCON0 = %00000111     ' Disable comparator
VRCON  = %00000000     ' disable
ADCON0 = %11100000
ANSEL  = %10000000

'       I/Os
gpio   = %00000000
TRISIO = %00000000      ' no inputs 

BOD var GPIO.0
POR var GPIO.1

   
IF PCON.1 = 0 and PCON.0 = 0 THEN BOD = 1	'BROWN OUT RESET BIT
IF PCON.1 = 0 				 THEN POR = 1	'POWER ON RESET BIT

PAUSE 1000

GPIO = 0

if PCON.1 = 1 AND PCON.0 = 0 then		'PCON.0 = BOD ;PCON.1 = POR
          
    GPIO.2 = 1         'GPIO.1 red led PIN6 shows a BOD state
    PAUSE 5000
    PCON.0 = 1
    gpio = %00000000
    
endif

PCON.1 = 1
PCON.0 = 1

While 1
Wend

END

This works really fine, but with a 10 µ (MICRO) F ...and a 12F683

so , some current draw improvements are still to add ...

NOTE: All Outputs are Mosfet Buffered ( BS 170 ) ...

Alain

PS: You didn't use your brain too much, here ....

[falingtrea]

Change your test circuit as follows:

Put a diode between the cap and the battery disconnect point like the sample schematic at the beginning of this thread has. This will isolate the PIC power from the rest of the circuit so that the cap will power the PIC when the battery is disconnected.

Connect the LED cathodes to the I/O pins. Then connect the LED anodes to the battery disconnect point between the battery and the diode that was added above. By doing this, the LEDs won't draw power once the battery is disconnected.

[peu]

[edit] Maybe I need to check for POR=1 and BOD=0 to know for sure that a BOD reset happened

I wasn't that far with this late edit

This works really fine, but with a 10 µ (MICRO) F ...and a 12F683

so , some current draw improvements are still to add ...

NOTE: All Outputs are Mosfet Buffered ( BS 170 ) ...

Alain

PS: You didn't use your brain too much, here ....

What brain?

Well I implemented your program and it worked, but the cap value was way too high, so I started lowering till I found a ridiculously low value...

Then I examined your code, removed some chunks and commented it:

@ device pic12f683,INTRC_OSC_NOCLKOUT , wdt_on, mclr_off, protect_off, bod_on

' I use picbasic to compile!!

 '@    __config _INTRC_OSC_NOCLKOUT & _PWRTE_ON & _WDT_ON &_BOD_ON & _MCLRE_OFF & _CP_OFF
 
 
OSCCON = %01100110
CMCON0 = %00000111     ' Disable comparator
VRCON  = %00000000     ' disable
ADCON0 = %11100000
ANSEL  = %10000000

'       I/Os
gpio   = %00000000
TRISIO = %00000000      ' no inputs 

' SECTION? what is this section used for?
' BOD var GPIO.0
' POR var GPIO.1

   
' IF PCON.1 = 0 and PCON.0 = 0 THEN BOD = 1	'BROWN OUT RESET BIT
' IF PCON.1 = 0 THEN POR = 1	'POWER ON RESET BIT

' PAUSE 1000  this pause cannot be used in a flashlight environment
'  SECTION?  what is this section used for?

GPIO = 0

if PCON.1 = 1 AND PCON.0 = 0 then		'PCON.0 = BOD ;PCON.1 = POR
          
    GPIO.2 = 1          'GPIO.2 green led PIN6 shows a BOD state
    PAUSE 1000          'I don't have patience :-)
    'PCON.0 = 1         ' not needed since you set this again below
    gpio = %00000000
    
endif

'PCON.1 = 1      replaced with one line :-)
'PCON.0 = 1
PCON=%00000011

GPIO.1 = 1 'normal state red led
While 1
Wend

END

and if a picture is a 1000 words, we could say that a video is like 1000 pictures, so 1000x1000=1000000 words... WOW... I just wrote a book take a look at this video: http://www.veoh.com/videos/v6415763hQHpjMDy

As you see, the cap is reaaally small, the green led shows BOD condition, and red led is normal operation. The diode you see there is not used. Also I left all the unused pins floating

When I used large value capacitors, everytime I did a power interruption no matter if it was 1 second or 10 the BOD led turned on.

I wonder why you had to use 10uF

Also assembled a proto PCB using the 1st schematic to start testing a real world application.

[Acetronics2]

I wasn't that far with this late edit

What brain?


.

" Whose brain ??? " could have been good level humour ...

Well I implemented your program and it worked, but the cap value was way too high, so I started lowering till I found a ridiculously low value...

Then I examined your code, removed some chunks and commented it:


<< ' I use picbasic to compile!! >>

Me too !!! ... did you notice a little difference between MPLAB and Microcode studio ???


<< I wonder why you had to use 10uF >>

I don't know ... gives me a ~ .3 s power interrupt delay ... and it won't be my headache !!!
The Pic itself draws .77 mA ...

Regards
Alain

[peu]

Alain, I just sent you a Private Message.

[edit] Sorry for the missunderstanding, and thanks for your reply