47 lines
2.1 KiB
Plaintext
47 lines
2.1 KiB
Plaintext
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See the top level README file for more information on documentation
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and how to run these programs.
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Derived from bootloader03, this is a very simple bootloader. Instead
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of the sd dance (see toplevel README), this makes life a bit simpler
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and greatly reduces physical wear and tear on the sd card socket. Do
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the sd card dance one more time with kernel.img. Get some sort of serial
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solution to connect a dumb termial program with xmodem capabilities
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to the uart on the raspberry pi. (see the toplevel README for more
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information).
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The difference between bootloader03 and bootloader05 is very subtle,
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first I dont like the config.txt thing and didnt want bootloader04 to
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be the biggest numbered bootloader. Second I use minicom and lrzsz
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as a dumb terminal and for xmodem transfers, there is a delay as
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lrzsz is ending and returning back to minicom so there is a delay.
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Bootloader05 has a loop that prints some numbers before it branches
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to the downloaded program.
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You take the .bin file of your test program, assumed to be built based
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on address 0x8000 and less than 0x200000-0x8000 bytes in size.
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With uart connected to a terminal
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1) power off raspberry pi
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2) power on raspberry pi
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3) use xmodem to transfer binary file
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Repeat for each new program to test
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This bootloader sits at 0x200000 so that you have 0x200000 bytes to
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develop with. And that way if you like your program you can just
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copy a .bin version to kernel.img on the sd card and use it. Fairly
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easy to change this address. bootloader05.c and vectors.s each have
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a copy of this value. bootloader04 uses a rasberry pi specific
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config file to move much deeper in memory giving you much more room
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if you want more room use that bootloader.
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bootloader01 uses .hex files, bootloader02 through bootloader05 use .bin
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files, .hex files wont work. Consider bootloader01 and 02 to be
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obsolete.
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I normally do not deliver binaries. In this case I have included all
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of the build files so that you can at least get started without having
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to build the bootloader. Backup whatever kernel.img file you are using
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and replace with the kernel.img file in this repo (on your sd card).
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