You are viewing an old version of this page. View the current version.

Compare with Current View Page History

« Previous Version 12 Next »

TE0320 is provided with a slide switch S2. S2 conditionally / unconditionally enables the 1.2 V and 2.5 V power rails.


Figure 33: Slide switch S2 (angle view).

When S2 is turned on (FX2 PON), the 1.2 V and 2.5 V power rails are controlled by the USB (EZ-USB FX2LP USB FX2) microcontroller. At start-up, the USB microcontroller switches off the 1.2 V and 2.5 V power rails and starts up the module in low-power mode. After enumeration, the USB microcontroller firmware switches the 1.2 V and 2.5 V power rails on, if enough current is available from the USB bus.

When S2 is turned off, the 1.2 V and 2.5 V power rails are always enabled.

S2 position

Effect on 1.2 V and 2.5 V rails

FX2 PON (on)(1)

1.2 V and 2.5 V rails controlled by USB FX2 microcontroller (signal FX2_PS_EN)

PON (off)

1.2 V and 2.5 V rails always enabled

 

 (1) default: FX2 PON

Table 14: Slide switch S2 settings overview (1.2 V and 2.5 V rails only).

Slide switch S2 conditions the value of signal PS_EN.

  • 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 could 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.

  • 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 under the standard assembly option.

power rail

S2= PON

S2 = FX2 PON and
PS_EN = FX2_PS_EN = 1

S2 = FX2 PON and
PS_EN = FX2_PS_EN = 0

1.2V

on

on

off

2.5V

on

on

off

VCCCIO0 (= 2.5V)
R131+R132- assembly (2)

on

on

off

VCCCIO0 (= 3.3V)
R131-R132+ assembly (3)

on

on

on

(1) R131 soldered / R132 unsoldered

(2) R131 unsoldered / R132 soldered

Table 14: Slide switch S2 settings overview ( 1.2V , 2.5V, VCCIO0).


 

  • No labels