ZED-F9P-Integration manual
Figure 19: SPI back-to-back read/write access
3.6.4 USB interface
A single USB port is provided for host communication purposes.
The USB interface is compatible with a USB version 2.0 FS (full speed, 12 Mb/s) interface.
The ZED-F9P receiver supports only self-powered mode operation in which the receiver is supplied
from its own power supply. The V_USB pin is used to detect the availability of the USB port, i.e.
whether the receiver is connected to a USB host.
USB suspend mode is not supported.
USB bus-powered mode is not supported.
It is important to connect V_USB to ground and leave data lines open when the USB
interface is not used in an application.
The voltage range for V_USB is specified from 3.0 V to 3.6 V, which differs slightly from the
specification for VCC.
The boot screen is retransmitted on the USB port after enumeration. However, messages
generated between boot-up of the receiver and USB enumeration are not visible on the USB
port.
There are additional hardware requirements if USB is to be used:
• Pin 38, V_USB needs to be powered by a separate LDO enabled by module VCC and supplied by
the USB host.
• A pull down resistor is required on the output of this V_USB LDO
• V_USB (pin 38) requires 1 uF capacitor mounted adjacent to the pin to ensure correct V_USB
voltage detection
• Apply USB_DM and USB_DP series resistors; typically 27 Ω
Figure 20: ZED-F9P example circuit for USB interface
UBX-18010802 - R08
3 Receiver functionality Page 41 of 110
Early production information
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