UM2191
System
architecture
DocID030479 Rev 2
27/55
Figure 22: STUSB1602 front end for Port 0
This circuit description uses port 0 for reference (see
Figure 22: "STUSB1602 front end for
Port 0"
), but the same applies to port 1.
The STUSB1602 device interacts with the STM32F072RBT6 microcontroller embedded in
the NUCLEO board via the following communication buses:
1.
I²C bus
: is used by the MCU to configure and control status of the device. This bus is
shared by both STUSB1602 devices, according to their I²C addresses (ADDR0).
Additionally, the STUSB1602 start-up profile can be fully customized by accessing its
integrated non-volatile memory via I²C.
2.
SPI peripheral
: is reserved for USB-PD messages. The BMC transceiver on the
STUSB1602 means that messages exchanged between the MCU and STUSB1602
are 5B coded (except the Preamble, as per the USB-PD specification).
The following MCU GPIOs are used for specific functions for each STUSB1602 device:
1.
TX_EN
is a control signal from the MCU to STUSB1602. It enables the BMC control
logic that will transfer data from the MCU serial interface, encode in BMC format and
drive the connected CC line.
2.
ALERT
signals specific events regarding CC detection, monitoring and fault condition
groups to the microcontroller. Each of these groups of events can be masked
configuring specific I²C registers.
3.
A_B_SIDE
pin provides cable orientation; this is also provided by an internal I²C
register.
4.
RESET
allows resetting of the device; this can be also accomplished via a specific I²C
register.
CC1 and CC2
configuration channel pins are for connection and attachment detection,
plug orientation and system configuration management across the USB Type-C cable.
CC1DB and CC2DB
are for dead battery mode when the STUSB1602 is configured in the
sink power role or dual power role. This mode allows systems powered by a battery to be
supplied by V
BUS
when the battery is fully discharged.
CC1
CC2
CC1DB
CC2DB
CC1
CC2
CC1
CC2
SDA
ALERT#
TX_EN
A_B_SIDE
VBUS
VBUS
RESET
ADDR0
CS
SCLK
MOSI
MISO
ISENSE
VSENSE
EN_SNK
EN_SRC
VCONN
V
I
SCL
+3V3
+3V3
+3V3
+3V3
+3V3
+3V3
+3V3
R203
10k
R204
10k
C201
1uF
R201
10k
R202
2.2k
C203
1uF
U200
STUSB1602
CC1DB
1
CC1
2
VCONN
3
CC2
4
CC2DB
5
RESET
6
SCL
7
SDA
8
ALERT#
9
GND
1
0
MOSI
1
1
NSS
1
2
ADDR0
13
MISO
14
TX_EN
15
SCLK
16
A_B_SIDE
17
VBUS_SENSE
18
VBUS_EN_SNK
19
VBUS_EN_SRC
20
VREG_1V2
21
VSYS
22
VREG_2V7
23
VDD
24
Exposed
2
5
TP200
TEST POINT N.M.
1
R205
10k
TP201
TEST POINT
1
TP203
TEST POINT N.M.
1
R209
10k
TP202
TEST POINT
1
R208
10k N.M.
C200
1uF
R200
10k
C202
1uF
R206
0
R207
0