Datasheet

SAM9G45 [DATASHEET]
Atmel-6438O-ATARM-SAM9G45-Datasheet_08-Dec-15
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10.5.3 USB Device Port
10.5.3.1 Supported External Crystal / External Clocks
The only frequency supported by SAM-BA Monitor to allow USB communication is a 12 MHz crystal or external
clock.
10.5.3.2 USB class
The device uses the USB communication device class (CDC) drivers to take advantage of the installed PC RS-232
software to talk over the USB. The CDC class is implemented in all releases of Windows
®
, beginning with
Windows 98SE
®
. The CDC document, available at www.usb.org, describes how to implement devices such as
ISDN modems and virtual COM ports.
The Vendor ID is Atmel’s vendor ID 0x03EB. The product ID is 0x6124. These references are used by the host
operating system to mount the correct driver. On Windows systems, the INF files contain the correspondence
between vendor ID and product ID.
10.5.3.3 Enumeration Process
The USB protocol is a master/slave protocol. The host starts the enumeration, sending requests to the device
through the control endpoint. The device handles standard requests as defined in the USB Specification.
The device also handles some class requests defined in the CDC class.
Unhandled requests are STALLed.
10.5.3.4 Communication Endpoints
There are two communication endpoints and endpoint 0 is used for the enumeration process. Endpoint 1 is a 64-
byte Bulk OUT endpoint and endpoint 2 is a 64-byte Bulk IN endpoint. SAM-BA Boot commands are sent by the
host through endpoint 1. If required, the message is split by the host into several data payloads by the host driver.
If the command requires a response, the host can send IN transactions to pick up the response.
Table 10-6. Handled Standard Requests
Request Definition
GET_DESCRIPTOR Returns the current device configuration value.
SET_ADDRESS Sets the device address for all future device access.
SET_CONFIGURATION Sets the device configuration.
GET_CONFIGURATION Returns the current device configuration value.
GET_STATUS Returns status for the specified recipient.
SET_FEATURE Used to set or enable a specific feature.
CLEAR_FEATURE Used to clear or disable a specific feature.
Table 10-7. Handled Class Requests
Request Definition
SET_LINE_CODING Configures DTE rate, stop bits, parity and number of character bits.
GET_LINE_CODING Requests current DTE rate, stop bits, parity and number of character bits.
SET_CONTROL_LINE_STATE RS-232 signal used to tell the DCE device the DTE device is now present.