Silicon Laboratories UDP C8051F960/Si1020 User Manual page 15

5. Using the UPMP-F960-EMIF with the UDP Motherboard
5.1. VBAT Selector Switch
When used with the UDP motherboard, the motherboard can power the UPMP-F960-EMIF MCU card. With the
VBAT selector switch in the VREG position, the motherboard powers the regulator on the card. With the VBAT
selector switch in the UDP position, the UDP motherboard powers VBAT directly. This position supports software
control of the variable voltage power supply and current measurements.
The S1 switch on the UDP motherboard selects between the fixed or programmable voltage. The variable supply is
controlled by the C8051F384 board control MCU through the U1 digital potentiometer. Use the fixed supply when
the variable supply is not under software control.
5.2. Current Measurement
The power measurement circuitry on the UDP motherboard consists of a Silicon Labs C8051F351 8051 MCU that
measures both input voltage and current consumption of the MCU card, I/O expander, and radio card. When using
the VBAT selector in the UDP position, install a shorting block on the UDP Motherboard J13 connecting the two left
pins together.
UDP motherboard
power
JP3
Downloaded from Elcodis.com electronic components distributor
I/O card IN
J15
power
R24
to I/O card
power
Figure 6. Power Measurement Diagram with Shorting Block
Radio card IN
J14
power
JP2
R15
to Radio card
power
C8051F351
Rev. 0.1
UPMP-F960-EMIF
J13
JP1 R6
to MCU card
power
MCU card IN
power
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