Hardware Development Guide of Module Product
20
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3.7
USB2.0 Interface
3.7.1
Description of PINs
ZM5202 has the high-speed USB2.0 interface, which supports both the full-speed
mode and the high-speed mode. The main processor (AP) is connected with the
module via the USB interface to transmit data.
3.7.2
Electric Feature
The USB interface complies with the USB2.0 specifications and the electric features.
USB_DP, USB_DA are wired strictly according to the differential mode, and the
length difference between the two cables should be restricted within 1mm.
Note: The differential impedance should be controlled within 90ohm.
It is recommended to connect to a high-speed common-mode echo filter on the USB
differential signal wire. If the cable is exposed to the external environment, it is
suggested to add a n ESB protection device. The power capacity of the ESD
protection device should be kept within 1.5pF.
3.7.3
Application of USB Interface
The USB bus is mainly used in data transmission, software upgrading and modular
program detection. Figure 3-4 shows a reference circuit design.
