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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 35: S2 on position FX2 PON (PS_EN = FX2_PS_EN = x ).
Full power operation ((PS_EN = high): when slide switch S2 is in the right position (PON = power rails unconditionally on), signal PS_EN is set to power rail 3.3V. Thus power rails 2.5V and 1.2V are unconditionally enabled.
Figure 34: S2 on position PON.
Power-rail 3.3V is not controlled by signal PS_EN and is unconditionally enabled.
Figure 38: Power rails 3.3V could not be enabled/disabled by signal PS_EN.
Table 14 summarizes all switching options implied by slide switch S2 and firmware signal FX2_PS_EN (under the standard assembly option).
power rail | S2= PON
| S2 = FX2 PON and (Dynamic full power) | S2 = FX2 PON and (Dynamic low power) |
---|---|---|---|
1.2V | on | on | off |
2.5V | on | on | off |
VCCCIO0 (= 2.5V) | on | on | off |
VCCCIO0 (= 3.3V) | on | on | on |
(2) R131 soldered / R132 unsoldered
(3) R131 unsoldered / R132 soldered
Table 14: Slide switch S2 settings overview ( 1.2V , 2.5V, VCCIO0).
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 35: S2 on position FX2 PON (PS_EN = FX2_PS_EN = x ).
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When slide switch S2 is in the right position (PON = power rails unconditionally on), signal PS_EN is set to power rail 3.3V. Thus power rails 2.5V and 1.2V are unconditionally enabled.
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