ST STM32F723IE, User Manual

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UM2140 Rev 3 15/48
UM2140 Hardware layout and configuration
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5.3.2 ST-LINK/V2-1 firmware upgrade
The ST-LINK/V2-1 embeds a firmware upgrade mechanism for in-situ upgrades through the
USB port. As the firmware may evolve during the lifetime of the ST-LINK/V2-1 product (for
example a new functionality, bug fixes, support for new microcontroller families), it is
recommended to visit the
www.st.com website before starting to use the
32F723EDISCOVERY board and periodically, to stay up-to-date with the latest firmware
version.
5.4 Power supply
The 32F723EDISCOVERY board is designed to be powered from a 5 V DC power source. It
is possible to configure the 32F723EDISCOVERY board to use any of the sources
described in the following
Table 4 .
Note: The Discovery board must be powered by a power supply unit or by auxiliary equipment
complying with the standard EN-60950-1: 2006+A11/2009, and must be Safety Extra Low
Voltage (SELV) with limited power capability.
5.4.1 Supplying the board through the ST-LINK USB port (default setting)
To power the 32F723EDISCOVERY board in this way the host PC USB gets connected with
the ST-LINK USB port through a USB Type-A to Micro-B cable.
5 V DC power is provided by V
BUS
from the CN1 USB type Micro-B connector of ST-
LINK/V2-1 (USB 5 V power source on ST-LINK silkscreen, refer to Figure 8 ). If the USB
enumeration succeeds (as explained below), the ST-LINK 5 V link power is enabled by
asserting the PWR_ENn signal. This pin is connected to the U1 ST890 power switch, which
powers the board. This power switch also features a current limitation to protect the PC in
case of a short-circuit on the board (current demand exceeding 700 mA).
The 32F723EDISCOVERY board can be powered from the CN1 ST-LINK USB connector,
but only the U2 STM32F103CBT6 is powered before USB enumeration because the host
PC only provides 100 mA to the board at that time. During the USB enumeration, the
32F723EDISCOVERY board asks for the 500 mA power to the host PC. Two events can
happen:
• If the host can provide the required power, the enumeration finishes by a
SetConfiguration command and then, the power transistor ST890 is switched ON, the
Table 4. 32F723EDISCOVERY board power configuration
CN8 configuration Power connector Voltage
ST-LINK CN1 5 V
USB_STLINK CN1 5 V
E5V CN3 5 V
E5V CN12 7 V-12 V => 5 V
USB_HS CN19 5 V
USB_FS CN18 5 V