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This document mainly introduces Quanzhi A40i The development board has rich hardware interface resources , And some precautions in the development and design . Quanzhi A40i Development board , It is the latest representative work of chuanglong Technology , Its core board adopts “100% domestic ＋ Industrial grade ” Design , Beautiful appearance , High playability , With the momentum of domestic chips growing , Is it really the first choice for power users ？ Let's see ！

Because the content is too long , Therefore, it is divided into three articles , This chapter is the first , The content covers in detail ： The power interface 、LED、BOOT SET Activate the selector dial switch 、KEY、 A serial port 、CAN Interface 、Micro SD Interface 、SPI FLASH 、RTC Seat, etc , Welcome all embedded fans to check .

Diagram of development board hardware resources 1

Diagram of development board hardware resources

A40i The processor IO The level standard is generally 1.8V and 3.3V, The pull-up power supply generally does not exceed 3.3V, When the external signal level is equal to IO In case of level mismatch , Level conversion chip or signal isolation chip shall be added in the middle . Keys or interfaces need to be considered ESD Design ,ESD When selecting devices, pay attention to whether the junction capacitance is too large , Otherwise, signal communication may be affected .

USB Interface

CON16(USB1 HOST) and CON17(USB2 HOST) by USB2.0 HOST Interface , Single layer Type-A Type connector ;CON18(USB0 OTG) by USB2.0 OTG Interface , use Micro USB The connector .