Datasheet

130
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
 Write commands: Write a byte (O), a halfword (H) or a word (W) to the target.
 Address: Address in hexadecimal.
 Value: Byte, halfword or word to write in hexadecimal.
 Output: ‘>’.
 Read commands: Read a byte (o), a halfword (h) or a word (w) from the target.
 Address: Address in hexadecimal
 Output: The byte, halfword or word read in hexadecimal following by ‘>’
 Send a file (S): Send a file to a specified address
 Address: Address in hexadecimal
 Output: ‘>’.
Note: There is a time-out on this command which is reached when the prompt ‘>’ appears before the end of the com-
mand execution.
 Receive a file (R): Receive data into a file from a specified address
 Address: Address in hexadecimal
 NbOfBytes: Number of bytes in hexadecimal to receive
 Output: ‘>’
 Go (G): Jump to a specified address and execute the code
 Address: Address to jump in hexadecimal
 Output: ‘>’
 Get Version (V): Return the SAM-BA boot version
 Output: ‘>’
21.4.1 DBGU Serial Port
Communication is performed through the DBGU serial port 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.
21.4.2 Xmodem Protocol
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
Figure 21-3 shows a transmission using this protocol.