When slide switch S2 is in the left position (FX2 PON = power rails conditionally on depending on signal FX2_PS_EN), signal PS_EN is set to signal FX2_PS_EN driven by the EZ-USB FX2LP USB FX2 microcontroller under user control.
Figure 34: Slide switch S2 schematic.
Figure 35: When slide switch S2 = FX2 PON, signal PS_EN is set to signal FX2_PS_EN driven by the EZ-USB FX2LP USB FX2 microcontroller under user control.
Signal PS_EN enables (high) or disables (low) power rails 2.5V and 1.2V.
Figure 36: Power rails 2.5V and 1.2V
According to the corresponding assembly option, power rail VCCCIO0 can depend or not on the 2.5V power rail. Image Added Figure 37: example of VCCIO0 assembly not dependent on 2.5V power rail. The other way is also possible.
Power-rail 3.3V is not controlled by signal PS_EN and is unconditionally enabled.
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Table 14 summarizes all switching options implied by slide switch S2 under the standard assembly option.