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47 lines
1.8 KiB
Markdown
47 lines
1.8 KiB
Markdown
# CMSIS from Atmel Software Foundation (ASF)
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The include files in the directory tree are copied from ASF. See
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https://spaces.atmel.com/gf/project/asf/frs/?action=FrsReleaseBrowse&frs_package_id=4
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(dd. 2016-07-15 ASF version 3.30 was used)
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The directory tree was copied "as is" and its structure is as follows:
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cmsis
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└── samd21
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├── include
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│ ├── component
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│ ├── instance
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│ └── pio
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└── source
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├── gcc
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└── iar
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There is only one include file (per CPU variant) that should be included in
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the source code. For SAMD21 that is cmsis/samd21/include/samd21.h. But
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that will only work if the proper define is set. The define is named after
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the variant, for example `__SAMD21J18A__`. This define must be set in the
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`Makefile.include` of the board.
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Be aware that if you want to make changes to any file in this tree that the
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changes will be lost when a new ASF release is going to be used.
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## Trailing White Space
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Because of the whitespace check (dist/tools/whitespacecheck/check.sh) all
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the trailing white space had to be removed. Please take this into account
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when comparing to the original ASF distribution.
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find include/ -name '*.h' -exec sed -i 's/\s*$//' '{}' +
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## LITTLE_ENDIAN
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These include files define `LITTLE_ENDIAN`. But we think this is wrong. It
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seems more logical to let the compiler decide in which mode the ARM code is
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to be translated. In include/machine/endian.h there is already a define of
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`LITTLE_ENDIAN` (and `BIG_ENDIAN`) for a different purpose.
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So, we decided to remove the define from the ASF CMSIS files. The command
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for it (running from this directory) is:
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find include/ -name '*.h' -exec sed -i '/^#define\s\s*LITTLE_ENDIAN/d' '{}' +
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