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This post was last edited by Hot Ximixiu on 2022-1-17 08:19
Hardware Reference
Functional Block Diagram
The main components and connections of ESP32-S3-USB-OTG are shown in the figure below.
ESP32-S3-USB-OTG Functional Block Diagram (click to enlarge)
Please note that the external interface corresponding to the USB_HOST D+ D- signal in the functional block diagram is USB DEV, which means that ESP32-S3 acts as a device to receive signals from other USB hosts. The external interface corresponding to the USB_DEV D+ D- signal is USB HOST, which means that ESP32-S3 acts as a host to control other devices.
Development Board Power Supply Selection
The development board has three power supply modes:
Powered by Micro_USB port
When using method 1 for power supply, use a USB cable (standard A to Micro-B) to connect the main control board to the power supply device and turn the power switch to OFF. Please note that only the main board and the display are powered in this power supply mode.
Powered by USB_DEV port
When using method 2 to supply power, DEV_VBUS_EN should be set to high level and the power switch should be set to OFF. This power supply mode can also supply power to the USB HOST interface. If a lithium battery is installed, it will also charge the lithium battery.
Powered by external lithium battery via battery interface
When using method 3 to supply power, BOOST_EN should be set to high level, the power switch should be set to ON, and a 1S lithium battery (3.7 V ~ 4.2 V) should be soldered to the power solder joint reserved on the back of the main control board. This power supply mode can also supply power to the USB HOST interface. The battery interface is shown in the figure below:
Battery connection diagram (click to enlarge)
USB HOST interface power supply selection
The USB HOST port (Type-A female port) can supply power to the connected USB device with a supply voltage of 5 V and a maximum current of 500 mA.
There are two power supplies:
Powered by the USB_DEV interface, the 5 V power comes directly from the power supply connected to this interface
Power is supplied through the lithium battery interface, and the 3.6 V ~ 4.2 V voltage of the lithium battery is boosted to 5 V through the Boost circuit. The working state of the Boost IC can be controlled by BOOST_EN/GPIO13, and GPIO13 is high to enable Boost.
Boost circuit diagram
(click to enlarge)
Power supply selection:
Power supply switching circuit diagram
500 mA Current Limiting Circuit
The current limiting IC MIC2005A can limit the maximum output current of the USB HOST interface to 500 mA. IDEV_LIMIT_EN (GPIO17) must be set to a high level to enable the current limiting IC so that the USB HOST interface can have voltage output.
500 mA current limiting circuit diagram
USB interface selection circuit
USB interface switching circuit diagram
When the USB_SEL (GPIO18) pin is high, the USB D+/D- (GPIO19, 20) signals will be connected to USB_DEV D+ D-, and other USB devices can be connected through the USB HOST interface (Type-A female port);
When the USB_SEL (GPIO18) pin is low, the USB D+/D- (GPIO19, 20) signals will be connected to USB_HOST D+ D-, and can be connected to other USB hosts through the USB DEV interface (Type-A male port);
By default, USB_SEL is low.
LCD Interface
LCD interface circuit diagram
Please note that this interface supports connecting to an SPI interface screen. The screen model used by this development board is: dev-kits:` ST7789 <esp32-s3-usb-otg/datasheet/ST7789VW_datasheet.pdf>`, and LCD_BL (GPIO9) can be used to control the screen backlight.
SD Card Interface
SD Card Interface Circuit Diagram
Please note that the SD card interface is compatible with both 1-wire, 4-wire SDIO mode and SPI mode. After power-on, the card will be in 3.3 V signaling mode. Send the first CMD0 command to select the bus mode: SD mode or SPI mode.
Charging Circuit
Charging circuit diagram
Please note that the Type-A male port can be connected to a power adapter with an output of 5 V. When charging the battery, the red indicator light on the charging circuit is on, and the red indicator light goes out when the battery is fully charged. When using the charging circuit, please turn the power switch to OFF. The charging current is 212.7 mA.
GPIO Assignment
Function pins:
Extended function pins:
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