5.11.5 USB

Pin

 

Name

 

Direction

 

Function

 

 

 

 

 

 

 

35

 

USBDP

 

In/Out

 

USB data positive

36

 

USBDN

 

In/Out

 

USB data negative

34

 

VUSB

 

Input

 

USB DC power

The USB interface is compliant with the USB2.0 standard for a full speed (12Mbps) endpoint device. Together with VUSB (the USB transceiver DC power) and GND it creates a standard USB 4-pin interface. VUSB (VBUS in the USB standard) is nominally 5.0V.

The USB interface has the following features

•Full-speed (12 Mbits/s) device operation

•16 unidirectional endpoints

•Each endpoint capable of supporting control, interrupt, isochronous and bulk transfer

•Programmable endpoint types and FIFO sizes and internal 1120-byte logical (2240-byte physical for dual-packet mode) shared FIFO storage allow a wide variety of configurations.

•Dual-packet mode of FIFOs reduces latency

•USB reset can be programmed to clear device address.

•Firmware ability to wake up and reset a suspended device

•8, 16, 32, and 64-byte FIFO sizes for non-isochronous transfers

•64, 256, 512, and 1024-byte FIFO sizes for isochronous transfers

•Firmware downloading

•Trace debug port for module diagnostics

The USB interface supports 3GPP TS 27.010 multiplexing, and may be used as the primary AT-command interface.

Internally, the USBDP line is pulled up by a 1.5K resistor, in accordance with the USB standard, to indicate that it’s a full-speed capable device to the USB controller.

To implement successful applications using the GS64 USB interface, users should familiarize themselves with the USB specification.

LZT 123 1836

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