AT91SAM9G46B-CU View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

AT91SAM9G46B-CU

SMART ARM-based Embedded MPU

Atmel Corporation 

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.

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.

The device also handles some class requests defined in the CDC class.

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.

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.

72 SAM9G46 Series [DATASHEET]

Atmel-11028G-ATARM-SAM9G46-Datasheet_08-Dec-15

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