TE0320 is provided with a slide switch S2.
S2 conditionally / unconditionally enables the 1.2 V and 2.5 V power rails.
Slide switch S2 conditions the value of signal PS_EN.
Figure 33: Slide switch S2 (angle view).
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To command signal FX2_PS_EN, read the reference firmware code.
IOD = 0x03; // Enable PS_ON EN and disable PROG_B
OED = 0x03; // Configure PS_ON EN and PROG as outputs
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When slide switch S2 is in the left position (= FX2 PON
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: power rails conditionally on depending on signal FX2_PS_EN), signal PS_EN is set to signal FX2_PS_EN (PS_EN = FX2_PS_EN) driven by the EZ-USB FX2LP USB FX2 microcontroller under user
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control (IOD and OED of fw.c).
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Figure 35:
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S2
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on position FX2 PON
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(PS_EN
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= FX2_PS_EN
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= high or low ).
Figure 36: Slide switch S2 schematic.
Figure 37: 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
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Figure 35: S2 on position FX2 PON (PS_EN = FX2_PS_EN = x ).
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control.
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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 (PS_EN ≠ FX2_PS_EN = x; PS_EN = high ).
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.
According to the corresponding assembly option, power rail VCCCIO0 can depend or not on the 2.5V power rail.
Figure 37: example of VCCIO0 assembly not dependent on 2.5V power rail. The other way is also possible.
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Table 14 summarizes all switching options implied by slide switch S2 and firmware signal FX2_PS_EN (under the standard assembly option).
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