Datasheet

65
SAM9X25 [DATASHEET]
11054E–ATARM–10-Mar-2014
Figure 11-11 shows a transmission using this protocol.
Figure 11-11.Xmodem Transfer Example
11.5.3 USB Device Port
11.5.3.1 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.
11.5.3.2 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
®
, from Windows 98SE
®
to
Windows XP
®
. 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.
11.5.3.3 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.
Host Device
SOH 01 FE Data[128] CRC CRC
C
ACK
SOH 02 FD Data[128] CRC CRC
ACK
SOH 03 FC Data[100] CRC CRC
ACK
EOT
ACK
Table 11-5. 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.