SAM3SD8B Atmel Corporation, SAM3SD8B Datasheet - Page 356

• Manufacturer Part Number: SAM3SD8B
• Manufacturer: Atmel Corporation

21.5.1
21.5.2
11090A–ATARM–10-Feb-12
11090A–ATARM–10-Feb-12
UART0 Serial Port
Xmodem Protocol
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-charac-
ter 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:
Figure 21-2
Figure 21-2. Xmodem Transfer Example
• Get Version (V): Return the SAM-BA boot version
– Output: ‘>’
– Output: ‘>’
– <SOH> = 01 hex
– <blk #> = binary number, starts at 01, increments by 1, and wraps 0FFH to 00H (not
– <255-blk #> = 1’s complement of the blk#.
– <checksum> = 2 bytes CRC16
to 01)
shows a transmission using this protocol.
Host
Section 21.2 ”Hardware and Software Constraints”
SOH 01 FE Data[128] CRC CRC
SOH 02 FD Data[128] CRC CRC
SOH 03 FC Data[100] CRC CRC
ACK
ACK
ACK
ACK
EOT
C
Device
SAM3S8/SD8
SAM3S8/SD8
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