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I trying to build a slave flash trigger for a digital camera.
with a programmed 12f629.
need a little help with the code.
digital cameras have 1 or 2 preflashes before the main flash.
using a photodiode to trigger a input to GPIO.2 I'm thinking if I can program it to ignore the first 2 flashes and give a output on GPIO.4 to fire the slave flash on the 3rd. it mite work.
what little programming I can do is with PBP and CDlite.
can anybody give me A jump start. Thanks
There are probably a gozillion various ways to do this, but since you're already using GP2, and this pin is the Timer0 clock input, maybe something like this?
Code:' // Internal RC OSC, WDT OFF, /MCLR reset function OFF
@ DEVICE INTRC_OSC_NOCLKOUT,WDT_OFF,MCLR_OFF
DEFINE OSCCAL_1K 1 ' Calibrate internal oscillator
GPIO = 0 ' All outputs to 0
TRISIO = %00000100 ' GPIO.2/T0CKI = input, rest outputs
CMCON = 7 ' Comparators OFF, all digital
' // Pull-ups on, TMR0 clock source = GP2/T0CKI input
' // Increment TMR0 on high-to-low transitions on GP2/T0CKI
' // Assign prescaler to WDT for 1:1 clocks on GP2/T0CKI
OPTION_REG = %00111000
' // Pre-load timer0 to over-flow on 3rd pulse on GP2/T0CKI
TMR0 = 253 ' 1st clk = 254, 2nd = 255, 3rd = over-flow & int
' // Enable global, peripheral & timer0 interrupts
INTCON = %11100000
On Interrupt Goto FireFlash
Main:
@ NOP
GOTO Main
DISABLE
FireFlash:
HIGH GPIO.4 ' Fire flash
PAUSEUS 500 ' Adjust for time you need to fire flash here
LOW GPIO.4
TMR0 = 253 ' Reload for 3rd pulse to trigger int
INTCON.2 = 0' Reset TMR0 int flag before leaving
RESUME ' Re-enable interrupts & return
ENABLE
END
deleted stuff... (Bruce had more useful info)
Arch
Thanks Bruce I will try it tomorrow.
I don't have to use GPIO.2 I just put that because That is what I normally use if it would be better to us another. I can and really if would be better for the whole operation If I did.
You can use whatever pins you might prefer if you're not using timer0 in counter mode as the pulse counter.
You also have timer1 that can function as a counter with the clock input on GP5 - or you could opt to count pulses in software.
I just showed "1" simple way out of many options.
I'm thinking that you'd probably want the processor to be asleep most of the time to save power.
If it was 'asleep' - could it wake up with an interrupt on the first pre-flash and be ready in time for the real flash? Don't know anything about the timing of the pre-flashes and such (or how long it takes the average PIC to wake-up from sleep) - but the 'real' flash will have to be in close sync with the cameras flash/shutter.
Arch
thank both of you
And Arch that what I had forgot Iam using the sleep and refesh to turn on the slave and to refesh the batteries. A interrupt on GPIO.2
wakes it up and turns the slave on (same time as camera).
which other pin is the best to trigger the flash using a counter overflow.
sorry I mixed thinks up. I need to show the whole project
I will post my code I wrote to do the power managment of the slave and then If yall will still help me. I can get it right.
codes at work will post later.
ok heres my code NO laughing
if I can use GPIO.4 input from the photodiode
and GPIO.1 as output to fire the flash that would work on the test board I have set up.
thanks
@ DEVICE pic12F629
@ DEVICE pic12F629, INTRC_OSC_NOCLKOUT
@ DEVICE pic12F629, WDT_ON
@ DEVICE pic12F629, MCLR_OFF
@ DEVICE pic12F629, CPD_OFF
@ DEVICE pic12F629, BOD_OFF
@ DEVICE pic12F629, PWRT_ON
@ DEVICE pic12F629, PROTECT_OFF
DEFINE OSC 4
Pause 20000 ' Allow pic to Stabilize
TRISIO = %00010100 ' make gpio 2 / 4 inputs
OPTION_REG.7 = 0 ' gpio 0 - 2 digital
WPU = 255 ' week pull ups on all pins
CMCON = 7 ' turn week pull ups on
SYMBOL SP = GPIO.0 'SLAVE POWER PIN 7
SYMBOL FLASH = GPIO.1 'FIRE FLASH PIN 6
SYMBOL GETREADY = GPIO.2 'GETREADY INPUT FROM CAMERA CONTROLLER PIN 5 SYMBOL TRIG =GPIO.4 'INPUT FROM PHOTODIODE TO TRIGGER FLASH PIN 3
SYMBOL LED = GPIO.5 'POWER OK PIN 2
SP= 0
FLASH =0
GETREADY=0
LED = 0
LED=1 'power up ok
Pause 4000
LED= 0
Pause 2000
SP =1 'turn slave on to charge cap.
Pause 8000
SP=0
MAIN
OPTION_REG=$0
ON INTERRUPT GoTo READY 'input from cam troller to get ready
INTCON=$90
REFRESH:
Sleep 14400 'give refresh charge to cap every 4hr. from interrupt
SP=1
Pause 10000
SP =0
GoTo REFRESH
Disable
READY:
SP =1
Pause 15000 'turns slave power on
SP=0
INTCON.1=0
Disable
GoTo MAIN
Enable
TTT
Hi ratsnest,
Do you have any ideas on the timing of the pre-flashes -
how long ON, and time between?
Arch
arch I'm clueless. should I use a learning mode like the store bought boards.( and no I do not know how to program that eather) I sent you a e-mail 1st. of the week did you get it.
any help on how I should handle this.
Here is the timing I used on an analog Digital flash trigger:Quote:
Originally Posted by ratsnest
http://www.pbase.com/sinoline/digital_slave_trigger