kopia lustrzana https://github.com/bristol-seds/pico-tracker
148 wiersze
4.3 KiB
Markdown
148 wiersze
4.3 KiB
Markdown
## samd20-gcc-blackmagic ##
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A simple GCC setup for Atmel SAM D20 development, intended for use with the
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[blackmagic debug probe](https://github.com/gsmcmullin/blackmagic).
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## Prerequisites ##
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[GNU Make](http://www.gnu.org/software/make/) and the following
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standard utilities are required: `cat`, `echo`, `find`, `grep`,
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`mkdir`, `rm`, `sed` and `tr`. If you're running any sensible desktop
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linux then these will already be installed.
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You will also need to aquire
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[GNU Tools for ARM Embedded Processors](https://launchpad.net/gcc-arm-embedded/).
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##### On Ubuntu
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```
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sudo add-apt-repository ppa:terry.guo/gcc-arm-embedded
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sudo apt-get update && sudo apt-get install gcc-arm-none-eabi
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```
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###### Note about gcc-arm-embedded on Ubuntu 14.04 and later
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If you are using Ubuntu 14.04 and later, please be careful because
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there are packages with same name but produced by Debian and inherited
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by Ubuntu. Simply follow the above 3 steps, you may end up with
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gcc-arm-none-eabi from Ubuntu. So to install gcc-arm-none-eabi from
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ARM, steps are:
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```
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1). sudo apt-get remove binutils-arm-none-eabi gcc-arm-none-eabi
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2). sudo add-apt-repository ppa:terry.guo/gcc-arm-embedded
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3). sudo apt-get update
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4). sudo apt-get install gcc-arm-none-eabi=4-8-2014q2-0trusty10
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```
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Meanwhile we are working with Debian to consolidate and unify this toolchain.
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## Usage ##
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### Project Options ###
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[`config.mk`](config.mk) allows configuation for individual
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projects. In particular the `PROJECT_NAME` and `TARGET_CHIP` variables
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needs to be set.
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### Compiling ###
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`make`
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## Backmagic ##
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### Download ###
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Run `arm-none-eabi-gdb`. If you have set `BLACKMAGIC_PATH` in
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[`config.mk`](config.mk) then gdb will attempt to connect to the
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blackmagic debugger. Otherwise you can use the `blackmagic` command to
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connect a `/dev/ttyACM<n>` device. For example `blackmagic 0` will
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connect to a blackmagic at `/dev/ttyACM0`.
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To attach to the SAM D20 chip itself you will need to run something like
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```
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monitor swdp_scan
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attach 1
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```
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You can place these commands in a `gdbscript-custom` file so that in
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future they will be run automatically. If `monitor swdp_scan` fails to
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detect an attached SAM D20 device then you may need to upgrade the
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firmware on your blackmagic to the latest version.
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To download code run
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```
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monitor erase_mass
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load
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```
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### Debugging ###
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You can start with the gdb command
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```
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run
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```
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You might want to use the command `set confirm off` so that you're not
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prompted each time. You might also want to `set mem
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inaccessible-by-default off` so that you can look at memory locations
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outside of RAM and ROM.
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These commands can be automated by placing them in a `gdbscript-custom` file.
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### Semihosting ###
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You can build for semihosting by defining the `SEMIHOSTING` variable
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in make. Like this:
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```
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make -kB SEMIHOSTING=1
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```
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This build will be significantly larger (in terms of RAM and ROM).
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For this build, when a debugger is present at startup the
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`semihost_printf`, `semihost_puts` and `semihost_putchar` functions
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will print to stdio on the host. The Blackmagic Debug Probe supports
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this.
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## Emacs ##
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The command `make emacs` can be used to quickly launch an instance of
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emacs with all the relavent source code loaded.
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A `TAGS` file can be generated with `make all` or `make tags`, and
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this can be used to automat navigate the source code. See the
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[emacs manual](https://www.gnu.org/software/emacs/manual/html_node/emacs/Tags.html)
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for more details.
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A Directory Local Variables File [`.dir-locals.el`](.dir-locals.el)
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exists in the root of the project. This has the following effects
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on emacs:
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### Fixed default-directory ###
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The default directory is fixed as the root of the project wherever you
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are within the project. As the makefile needs to be run from the root
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of the project, this means that `M+x compile` will always run the
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top-level makefile no matter which file you are editing.
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### Custom GDB ###
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`M+x gdb` is set to use `arm-none-eabi-gdb` rather than the default GDB for your
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machine.
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## Other notes ##
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Wherever possible use
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[Function Attributes](http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html)
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and
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[Variable Attrubutes](http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html)
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rather than editing the project's linker files.
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## Sources & Licensing ##
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See [LICENSE.md](LICENSE-samd20-gcc-blackmagic.md)
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