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When S2 is turned off (open, PON), the 1.2 V and 2.5 V power rails are always enabled (switched on).
When S2 is turned on (FX2 PON), make sure that no signals are applied to the input pins when power-rails are disabled by the USB microcontroller (at start-up). |
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S2 position | Default position | Effect on 1.2 V and 2.5 V rails |
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FX2 PON (on, closed) | Power rails 1.2 V and 2.5 V controlled by USB FX2 microcontroller (signal FX2_PS_EN) PS_EN = FX2_PS_EN = 1 or 0 | |
PON (off, open) | Power rails 1.2 V and 2.5 V always enabled (PS_EN = 1) PS_EN ≠ FX_PS_EN = 1 or 0 |
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