I have custom target board with BF518.
Initial booting is made over UART.
It's interesting for me where (what document) can I view UART boot stream format?
Is it a specific file format you're interested in, or just the general formatting of the boot stream? If it's the expected byte layout in a boot stream, take a look at the BF518 Processor Hardware Reference Manual (available at http://www.analog.com/blackfin/manuals).
Basically, the stream is organised in blocks. Every block has a 16-byte Block Header, and certain block types have an additional Payload, which is variable in size. The Block Header has 4 fields, each 4 bytes, that tell the Boot Kernel about that block:
<Block Code> (4 bytes)
<Target Address> (4 bytes)
<Byte Count> (4 bytes)
<Argument> (4 bytes)
Basically, the Block Code tells you what type of Block it is, the Target Address tells you where it should be copied to, the Byte Count tells you how many bytes should be written to by this block (either as a fixed value from a Fill Block, or from the Payload if it's a regular data block), and th Argument Field serves different purposes for different block types - for example, in a Fill Block the Argument Field holds the value that should be written 'Byte Count' times starting at 'Target Address'.
Take a look at the "System Reset and Booting" chapter of the BF518 Processor Hardware Reference Manual for more detail - specifically the 'Basic Booting Process' section.
I am sorry, It is my inattentiveness.
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