Atmel Xplained Pro Evaluation Kit ATSAM4E-XPRO ATSAM4E-XPRO Data Sheet

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SAM4E [DATASHEET]

Atmel-11157D-ATARM-SAM4E16-SAM4E8-Datasheet_12-Jun-14

Communication is performed through the UART0 initialized to 115200 Baud, 8, n, 1.

The Send and Receive File commands use the Xmodem protocol to communicate. Any terminal performing this
protocol can be used to send the application file to the target. The size of the binary file to send depends on the
SRAM size embedded in the product. In all cases, the size of the binary file must be lower than the SRAM size
because the Xmodem protocol requires some SRAM memory to work. See 

The Xmodem protocol supported is the 128-byte length block. This protocol uses a two-character CRC-16 to
guarantee detection of a maximum bit error.

Xmodem protocol with CRC is accurate provided both sender and receiver report successful transmission. Each
block of the transfer looks like:

<SOH><blk #><255-blk #><--128 data bytes--><checksum> in which:

̶

<SOH> = 01 hex

̶

<blk #> = binary number, starts at 01, increments by 1, and wraps 0FFH to 00H (not to 01)

̶

<255-blk #> = 1’s complement of the blk#.

̶

<checksum> = 2 bytes CRC16 

 shows a transmission using this protocol.

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 a way to implement devices such as ISDN
modems and virtual COM ports. 

The Vendor ID (VID) is Atmel’s 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. 

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