Datasheet

855
SAM9263 [DATASHEET]
Atmel-6249N-ATARM-SAM9263-Datasheet_14-Mar-16
42.4 Typical Connection
Figure 42-2. Board Schematic to Interface Device Peripheral
42.4.1 USB Device Transceiver
The USB device transceiver is embedded in the product. A few discrete components are required as follows:
 the application detects all device states as defined in chapter 9 of the USB specification;
 VBUS monitoring
 to reduce power consumption the host is disconnected
 for line termination.
42.4.2 VBUS Monitoring
VBUS monitoring is required to detect host connection. VBUS monitoring is done using a standard PIO with
internal pullup disabled. When the host is switched off, it should be considered as a disconnect, the pullup must be
disabled in order to prevent powering the host through the pull-up resistor.
When the host is disconnected and the transceiver is enabled, then DDP and DDM are floating. This may lead to
over consumption. A solution is to connect 330 KΩ pulldowns on DP and DM. These pulldowns do not alter DDP
and DDM signal integrity.
A termination serial resistor must be connected to DP and DM. The resistor value is defined in the electrical
specification of the product (R
EXT
).
R
EXT
R
EXT
DDM
DDP
PIO
27 K
47 K
330 K
Type B
Connector
12
34
5V Bus Monitoring
330 K