Atmel ARM-Based Evaluation Kit AT91SAM9N12-EK AT91SAM9N12-EK データシート
製品コード
AT91SAM9N12-EK
105
SAM9N12/SAM9CN11/SAM9CN12 [DATASHEET]
11063K–ATARM–05-Nov-13
12.2.5.3 USB Device Port
Supported External Crystal / External Clocks
The frequencies supported by SAM-BA Monitor to allow USB communication are 4, 8, 12 or 16 MHz crystal or external
clock.
clock.
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
software to talk over the USB. The CDC class is implemented in all releases of Windows
®
, from Windows 98SE
®
to
Windows XP
®
. The CDC document, available at
, 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.
system to mount the correct driver. On Windows systems, the INF files contain the correspondence between vendor ID
and product ID.
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 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.
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.
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 12-6. 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 12-7. Handled Class Requests
Request
Definition
SET_LINE_CODING
Configures DTE rate, stop bits, parity and number of
character bits.
character bits.
GET_LINE_CODING
Requests current DTE rate, stop bits, parity and number
of character bits.
of character bits.
SET_CONTROL_LINE_STATE
RS-232 signal used to tell the DTE device is now present.