Five I/Os are used to manage the USB Type-C
®
connection: two configuration channels (CCx) connected on ADC
inputs, a VBUS_SENSE on ADC input, a Dead Battery (UCPD.DBn) and a fault (UCPD.FLT) on GPIOs.
• Configuration Channel I/O (UCPD.ADCx): These signals are connected to the associated CCx line of the
USB Type-C
®
connector through the STM USB‑port protection TCPP01-M12. These lines are used for
the configuration channel lines (CCx) to sense the cable orientation and identify Power source capability.
STM32U5A9J-DK supports only sink current mode with the default 5V power supply with up to 3 A current.
To be compatible with the 1.8 V ADC voltage range, a resistor bridge is present between CCx lines and
UCPD.ADCx inputs: it presents a total 5.1 kΩ pull-down on the USB connector and adapts the voltages
from CCx lines to the maximum 1.8 V range of MCU inputs. According to the USB Type-C
®
specification,
the following thresholds must be used in the context of MB1829 to identify the Host Source capability:
Table 10. UCPD.ADCx voltage range and threshold according to Power source capability
Source advertisement
Minimum voltage on
UCPD.ADCx
Maximum voltage on
UCPD.ADCx
Threshold between modes
Default USB Power (500 mA) 0.24 V 0.44 V 0.54 V
1.5 A @ 5 V 0.63 V 0.84 V 1 V
3 A @ 5 V 1.16 V 1.49 V -
To measure UCPD.ADCx inputs, UCPD_DBn must be set to high before (see below).
• Dead Battery I/O (UCPD_DBn, PE9): This signal is connected to the associated DBn line of the TCPP01-
M12. When UCPD.DBn is low, the STM USB port protection TCPP01-M12 manages internally the Dead
Battery resistors on CCx lines that enables 5V, and at least 500 mA default mode. When going High,
UCPD.DBn connects ADCx lines of the microcontroller to the connector and enables it to sink more current
than 500 mA (in the limit of 3 A). Thus, if UCPD.DBn is not set to the high level, STM32U5A9J-DK must not
consume or activate used cases requiring more than 500 mA.
• V
BUS
fault detection: UCPD.FLT (PE12, interrupt active low). This signal is provided by the STM USB Type-
C
®
port protection TCPP01-M12. It is used as fault reporting to MCU after a bad V
BUS
level detection. By
design, the OVP V
BUS
protection is set to 6.5 V nominal (7 V max) which is compatible with the absolute
maximum ratings of the design. OVP V
BUS
= 1.25 x (10 kΩ + 2.4 kΩ) / 2.4 kΩ.
• VBUS_SENSE ADC input (PG1) is used to detect attach and detach, and to measure accurate V
BUS
voltage at JP4 header (5V_UCPD).
During start‑up, the DBn pin of TCPP01-M12 is tied to GND, and CC lines are managed directly by TCPP01-M12:
It enables the Host source to power the 5V V
BUS
by default. A green LED (LD2) is lit when 5V is present.
TCPP01-M12 controls a FET switch and protects the Discovery kit against V
BUS
overvoltage. Moreover, in any
case, to ensure the functional behavior of the kit, the recommended voltage applied on VBUSc must be lower
than 5.5 V in continuous mode.
Note: UCPD.ADC1 and UCPD.ADC2 functions are exclusive with respectively ADC4_IN6 and ADC4_IN7 functions of
expansion connector (CN10). Solder bridges can handle it, refer to Table 33. Solder bridge configuration.
12.2.2 USB 2.0 high‑speed interface
To achieve the highest transfer data rate in USB 2.0 mode, STM32U5A9J-DK offers a high‑speed connection of
up to 480 Mbit/s. This allows limited time to transfer data into the embedded 4‑Gbyte eMMC flash memory for
example.
12.2.3
USB Type-C
®
function interface
Table 11. USB Type-C
®
function interface
PIO
Configuration
PE12 FLT (UCPD.FLT)
PE9 DBn (UCPD.DBn)
PG0 ADC1 (UCPD.ADC1) - optionally used
UM2967
USB Type-C® (High Speed, sink only)
UM2967 - Rev 1
page 30/68
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