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USB wake up for A450 A460 and pulse width

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Offline zcream

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USB wake up for A450 A460 and pulse width
« on: 30 / January / 2011, 05:35:48 »
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Two qs.
1. Does the A450 A460 support USB wakeup yet ?
2. What are the input pulse widths for a.) wakeup b.) shoot_full ?
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Offline fudgey

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Re: USB wake up for A450 A460 and pulse width
« Reply #1 on: 30 / January / 2011, 10:29:45 »
Quote from: zcream on 30 / January / 2011, 05:35:48
Two qs.
1. Does the A450 A460 support USB wakeup yet ?
2. What are the input pulse widths for a.) wakeup b.) shoot_full ?

Wakeup? Yet? Afaik, only some older cameras (and possibly some newer higher end cameras?) wake up (from power off) when USB supply rises and CHDK can't change this as it's supposedly a hardware feature. The way around this is to mechanically force the power button down and toggle external power supply, but care must be taken when shutting down to prevent sd card file system corruption.

I don't know how long pulses are sufficient, but since shooting always takes a while, there shouldn't be much reason to use pulse widths narrower than, say, 100 ms for just shooting (assuming rising edge trigger).
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