LZT 123 1836
58
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.
