Hardware basics/zh-hans
我们将在该节里说明 Nano 中的一些硬件基础。
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框图
电源
振荡器
启动
Jz4720 支持 3 种不同的启动源。启动顺序由 boot_sel 引脚值 [1:0] 控制。The configuration of BOOT_SEL1 and BOOT_SEL1 [1:0] is showed as below:
| BOOT_SEL0 | BOOT_SEL1 | action |
|---|---|---|
| 0 | 0 | 从外部 ROM 启动，GPIO 初始为 CS4_ 状态 |
| 0 | 1 | 从 USB 设备启动 |
| 1 | 0 | 以 512 bytes 页大小的 NAND flash 启动， GPIO 初始为 CS1_ 状态 |
| 1 | 1 | 以 2048 bytes 页大小的 NAND flash 启动， GPIO 初始为 CS1_ 状态 |
存储器
Is necesary, for the operation of the Nanonote Board store many sections of executable programs in volatile and non-volatile memories. The volatile memories are used like Random Acces Memories (RAM) because to its low acces time and unlimit number of Read/Write cycles. Moreover, the Non-volatile memories (NAND, SD) stores for longs periods of time the required information to operation of the Embedded System.
音频
LCD
USB
Universal Serial Bus (USB) is a way of setting up communication between a computer and peripheral devices. USB is intended to replace many varieties of serial and parallel ports. USB can connect computer peripherals such as mice, keyboards, PDAs, gamepads and joysticks, scanners, digital cameras, printers, personal media players, flash drives, and external hard drives. For many of those devices, USB has become the standard connection method.
A USB system has an asymmetric design, consisting of a host, a multitude of downstream USB ports, and multiple peripheral devices connected in a tiered-star topology. Additional USB hubs may be included in the tiers, allowing branching into a tree structure with up to five tier levels. A USB host may have multiple host controllers and each host controller may provide one or more USB ports. Up to 127 devices, including the hub devices, may be connected to a single host controller.
