DocID029088 Rev 3
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UM2036
Hardware layout and configuration
79
1.
If more than 300 mA current is needed by the board, the PC may be damaged or the
current can be limited by PC. As a consequence the board is not supplied correctly.
2. 300 mA will be requested at enumeration (since JP27 must be off), so there is the risk
that the request is rejected and the enumeration does not succeed if the PC cannot
provide such current. Consequently the board is not powered (LED LD10 remains off).
Note:
In case the board is powered by a USB charger, there is no USB enumeration, so the led
LD10 remains set to off permanently and the board is not powered. In this specific case only
the jumper JP27 must be set to on, to allow the board to be powered anyway but in any
case the current will be limited to 600 mA by U17 (ST890).
The power supply is configured by setting the related jumpers
JP2, JP15 and JP20
as
described in
Table 2. Power-supply-related jumper settings
Jumper
Description
JP2
JP2 is used to measure the STM32 current consumption manually by multimeter.
Default setting: Fitted
JP15
V
bat
is connected to +3.3 V when JP15 is set, as shown to the right: (Default setting)
V
bat
is connected to the battery when JP15 is set, as shown to the right:
JP20
JP20 is used to select one of the six possible power supply resources.
STM32F779I-EVAL is supplied through the jack CN19, when JP20 is set as shown
to the right: (Default Setting)
STM32F779I-EVAL is supplied through the USB connector of the ST-LINK MCU,
when JP20 is set as shown on the right
(Default Setting)
+6
)6
)6
'9
368
67ON
069
+6
)6
)6
'9
368
67ON
069
