Description
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5.2.6
Local USB
When the local 12V power supply source is not available, a subset of EVM functionality is available using
only power from the local USB source (3P3V_USB). Install J8 (3.3VUSB) and remove J4 when this
operation is desired. Communication to the UCD90120/4 is possible but power supply sequencing and
operation is not.
5.3
Test/Debug and Status
5.3.1
GPIO Expansion
J73 and J74 provide EVM to system board expansion capability as well as an HP type logic analyzer
interface.
5.3.2
Status LEDs
Visual status information for the GPI, GPIO, and PMBus signals (control and alert) is provided. Logic high
at GPI1-4 or GPIO1-22 will illuminate the associated LED. The GPIO status LEDs can be enabled (EN) or
disabled (EN bar) through the use of S10 to prevent the LED bias from affecting the logic state of the
GPIO signal during device reset.
5.4
Digital I/O Terminations
5.4.1
General Purpose Input/Output Terminations
GPIO1-22 can be pulled up or down with a 10k
Ω
resistor using jumpers. GPIO14 and GPIO15 can also be
used as voltage margining inputs.
5.4.2
General Purpose Input Terminations
GPI1-4 can be pulled up or down with a 10k
Ω
resistor using jumpers.
5.5
Analog Monitor Inputs
The UCD90120/4 monitor inputs MON1-13 can be used to monitor onboard or off board voltages.
Jumpers are used to select the analog source.
5.5.1
MON1 and MON4–MON11
MON1 and MON4-11 can be sourced by the onboard rail (L#) or an external (E#) voltage.
5.5.2
MON2, MON3, MON12 and MON13
MON2 can be sourced by the onboard rail (L2), an external (E2) or the on board temperature sensor (T1)
voltage. MON3 can be sourced by the onboard rail (L3), an external (E3) or the on board current monitor
(C1) voltage. MON12 can be sourced by onboard rail (12L), an external source (12E) or the onboard fan
temperature potentiometer input (TEMP MON) voltage. MON13 can be sourced by the V33D or 12VBUS
voltage.
5.5.3
Monitor Scaling
For the external monitor jumper positions (E1-E4), the external supply can be scaled by a selectable factor
of 2 for monitoring external voltages up to 5V or 6 for monitoring external voltages up to 15V. For MON13,
the scale factor is 6 for the 12VB position and 2 for the V33D position. For all other MON jumper positions,
the scale factor is 2.
5.5.4
Monitor Fault Injection
Under voltage or over voltage faults can be injected on MON 5–MON12 through the use of on board
switches (S2, S4, S6, S8, S3, S5, S7, S9 respectively). The switches provide a fault bias on the nominal
voltage of approximately ±20%
16
Evaluation Module for UCD90120 and UCD90124
SLVU347 – December 2009
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