Laird Sterling-EWB, Руководство пользователя

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SW1 is SPST-NO tact switch connected to Port PA0 on the EWB STM32F412 MCU to provide the ability to use the WKUP
function of the MCU to wake from Standby, Stop, and Sleep modes of operation.
The development board includes the Bosch Sensortec BME680 air quality sensor connected to the EWB MCU I2C2 interface
bus via pins PB10 (SCL) and PB11 (SDA). The I2C signal traces are pulled high on the development board.
The EWB development board provides the capability to connect to an external host MCU that uses 1.8V - 5.0V logic levels.
The following peripherals and pin assignments of the EWB STM32F412 MCU are available on header J4 for connection to an
external microcontroller host platform (
Table 5 ).
Table 5: External host Interface connections
J4 Pin # Name Function Type
EWB STM32F412
Port
1 GND Ground I -
2 VCC_EXT_MCU External Host I/O Voltage
[1]
I -
3 UART_CTS CTS flow control (to external host) O UART3_RTS/PB14
4 UART_TX TX Data (from external host) I UART3_RX/PC5
5 UART_RX RX Data (to external host) O UART3_TX/PD8
6 UART_RTS RTS flow control (from external host) I UART3_CTS/PB13
7 RESETn EWB MCU reset I MICRO_RST_N
8 WKUPn EWB MCU wake I MICRO_WKUP/PA0
9 BT_WAKE
Wake up Signal indicating EWB Bluetooth device
requires attention
O
BT_HOST_WAKE
10 GPIO General Purpose I/O I/O PE5
11 OEn Level Shifter enable (active low)
[2]
I -
12 GND Ground I -
Note: By default, EWB 3V3_MCU power is not provided to the level shifter interface IC on the development board.
[1]
Connect EWB module 3V3_MCU to the level shifter and set the logic level for the module interface lines by
shorting solder bridge SB3 on the development board ( Figure 7 ).
[2]
The OEn line is held low by default on the development board. J4 - pin 11 provides the option for the external
host microcontroller to control this line. To allow this capability, the shorted solder bridge SB4 needs to be cut on
the development board (
Figure 7 ).