Datasheet

Figure 17-2. Xmodem Transfer Example

Host Device

SOH 01 FE Data[128] CRC CRC

ACK

SOH 02 FD Data[128] CRC CRC

ACK

SOH 03 FC Data[100] CRC CRC

ACK

EOT

ACK

17.6.3 USB Device Port

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 a way to implement devices such as ISDN modems

and virtual COM ports.

The Vendor ID (VID) is the Atmel vendor ID 0x03EB. The product ID (PID) 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.

For more details on VID/PID for end product/systems, refer to the Vendor ID form available from the USB

Implementers Forum found at http://www.usb.org/.

WARNING

Unauthorized use of assigned or unassigned USB Vendor ID Numbers and associated Product ID

Numbers is strictly prohibited.

17.6.3.1 Enumeration Process

The USB protocol is a master/slave protocol. This is the host that starts the enumeration sending requests to the

device through the control endpoint. The device handles standard requests as defined in the USB Specification.

able 17-3. 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 Set or Enable a specific feature.

CLEAR_FEATURE Clear or Disable a specific feature.

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

SAM E70/S70/V70/V71 Family

SAM-BA Boot Program

echnology Inc.

Datasheet

DS60001527D-page 81