Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD Data Sheet
Product codes
ATSAM4S-WPIR-RD
1005
SAM4S Series [DATASHEET]
Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14
40.5
Typical Connection
Figure 40-2.
Board Schematic to Interface Device Peripheral
40.5.1 USB Device Transceiver
The USB device transceiver is embedded in the product. However, discrete components are required for each of
the following actions:
to monitor VBUS voltage
for line termination
to disconnect the host for reduced power consumption
40.5.2 VBUS Monitoring
VBUS monitoring is required to detect host connection. VBUS monitoring is done using a standard PIO with
internal pull-up disabled. When the host is switched off, it should be considered as a disconnect, the pull-up 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
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 enable the integrated pull-down by disabling the transceiver (TXVDIS = 1) and
then remove the pull-up (PUON = 0).
A termination serial resistor must be connected to DDP and DDM. The resistor value is defined in the electrical
A termination serial resistor must be connected to DDP and DDM. 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
Type B
Connector
1
2
3
4
5V Bus Monitoring