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Powering a micro SD card from Prop pins? — Parallax Forums

Powering a micro SD card from Prop pins?

HughHugh Posts: 362
edited 2013-07-22 15:26 in Propeller 1
Would I be hopelessly naive to try to supply Gnd and 3.3V to a micro SD card socket by using prop pins set low and high?

Thanks
Hugh

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2013-07-22 08:15
    The main problem is that peak current for some SD cards can be well over the 40mA that a Propeller I/O pin is capable of. There are ways around this because the peak current is transient and the average current is well below the maximum, but the fixes would be much more complicated than just running the SD card off the Prop's power supply.
  • HughHugh Posts: 362
    edited 2013-07-22 08:33
    Mike Green wrote: »
    The main problem is that peak current for some SD cards can be well over the 40mA that a Propeller I/O pin is capable of. There are ways around this because the peak current is transient and the average current is well below the maximum, but the fixes would be much more complicated than just running the SD card off the Prop's power supply.

    That's a 'yes' to hopeless na
  • Mike GreenMike Green Posts: 23,101
    edited 2013-07-22 08:46
    There's a big difference between wishful thinking and hopeless na
  • prof_brainoprof_braino Posts: 4,313
    edited 2013-07-22 10:37
    So you really need tp use the prop pin to supply power. or just control power?

    For example, use a transistor controled by a prop pin to switch poweroff?
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-07-22 15:26
    Cluso99 recently posted a thread about using Prop pins for power. His warning about adding medium to large capacitor probably saved me from killing yet another Prop.
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