39.3. USB Block Diagram
39.4. Signal Description
Pin Name
Pin Description
Type
DM
Data -: Differential Data Line - Port
Input/Output
DP
Data +: Differential Data Line + Port
Input/Output
SOF 1kHZ
SOF Output
Output
Refer to
I/O Multiplexing and Considerations
for details on the pin mapping for this peripheral. One signal
can be mapped on several pins.
Related Links
I/O Multiplexing and Considerations
on page 27
39.5. Product Dependencies
In order to use this peripheral module, other parts of the system must be configured correctly, as
described below.
39.5.1. I/O Lines
The USB pins may be multiplexed with the I/O lines Controller. The user must first configure the I/O
Controller to assign the USB pins to their peripheral functions.
A 1kHz SOF clock is available on an external pin. The user must first configure the I/O Controller to
assign the 1kHz SOF clock to the peripheral function.
39.5.2. Power Management
This peripheral can continue to operate in any sleep mode where its source clock is running. The
interrupts can wake up the device from sleep modes. Events connected to the event system can trigger
other operations in the system without exiting sleep modes.
Related Links
39.5.3. Clocks
The USB bus clock (CLK_USB_AHB) can be enabled and disabled in the Power Manager, and the
default state of CLK_USB_AHB can be found in the
Peripheral Clock Masking
.
A generic clock (GCLK_USB) is required to clock the USB. This clock must be configured and enabled in
the Generic Clock Controller before using the USB. Refer to
GCLK - Generic Clock Controller
for further
details.
This generic clock is asynchronous to the bus clock (CLK_USB_AHB). Due to this asynchronicity, writes
to certain registers will require synchronization between the clock domains. Refer to
GCLK
Synchronization
for further details.
The USB module requires a GCLK_USB of 48 MHz ± 0.25% clock for low speed and full speed operation.
To follow the USB data rate at 12Mbit/s in full-speed mode, the CLK_USB_AHB clock should be at
minimum 8MHz.
Atmel SAM L22G / L22J / L22N [DATASHEET]
Atmel-42402E-SAM L22G / L22J / L22N_Datasheet_Complete-07/2016
920