stlink/README.md

Open source version of the STMicroelectronics Stlink Tools
==========================================================

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## HOWTO

First, you have to know there are several boards supported by the software.
Those boards use a chip to translate from USB to JTAG commands. The chip is
called stlink and there are 2 versions:

* STLINKv1, present on STM32VL discovery kits,
* STLINKv2, present on STM32L discovery and later kits.

Two different transport layers are used:

* STLINKv1 uses SCSI passthru commands over USB
* STLINKv2 uses raw USB commands.

## Common requirements

* Debian based distros (debian, ubuntu)
  * `build-essential`

* `cmake`
* `libusb-1.0` (plus development headers for building, on debian based distros `libusb-1.0.0-dev` package)
* (optional) for `stlink-gui` we need libgtk-3-dev

## For STLINKv1

The STLINKv1's SCSI emulation is very broken, so the best thing to do
is tell your operating system to completely ignore it.

Options (do one of these before you plug it in)

* `modprobe -r usb-storage && modprobe usb-storage quirks=483:3744:i`
* or 1. `echo "options usb-storage quirks=483:3744:i" >> /etc/modprobe.conf`
*    2. `modprobe -r usb-storage && modprobe usb-storage`
* or 1. `cp stlink_v1.modprobe.conf /etc/modprobe.d`
*    2. `modprobe -r usb-storage && modprobe usb-storage`

## For STLINKv2

You're ready to go :)

## Build from sources

```
$ mkdir build && cd build
$ cmake -DCMAKE_BUILD_TYPE=Debug ..
$ make
```

### Build Debian Package
To build debian package you need debuild.

```
$ git archive --prefix=$(git describe)/ HEAD | bzip2 --stdout > ../libstlink_$(sed -En -e "s/.*\((.*)\).*/\1/" -e "1,1 p" debian/changelog).orig.tar.bz2
$ debuild -uc -us
```

## Using the gdb server

To run the gdb server: (you do not need sudo if you have set up
permissions correctly)

```
$ make && [sudo] ./st-util

There are a few options:

./st-util - usage:

  -h, --help		Print this help
  -vXX, --verbose=XX	Specify a specific verbosity level (0..99)
  -v, --verbose		Specify generally verbose logging
  -s X, --stlink_version=X
			Choose what version of stlink to use, (defaults to 2)
  -1, --stlinkv1	Force stlink version 1
  -p 4242, --listen_port=1234
			Set the gdb server listen port. (default port: 4242)
  -m, --multi
			Set gdb server to extended mode.
			st-util will continue listening for connections after disconnect.
  -n, --no-reset
			Do not reset board on connection.
```

The STLINKv2 device to use can be specified in the environment
variable STLINK_DEVICE on the format `<USB_BUS>:<USB_ADDR>`.

Then, in your project directory, someting like this...
(remember, you need to run an _ARM_ gdb, not an x86 gdb)

```
$ arm-none-eabi-gdb fancyblink.elf
...
(gdb) tar extended-remote :4242
...
(gdb) load
Loading section .text, size 0x458 lma 0x8000000
Loading section .data, size 0x8 lma 0x8000458
Start address 0x80001c1, load size 1120
Transfer rate: 1 KB/sec, 560 bytes/write.
(gdb)
...
(gdb) continue
```

Have fun!

## Resetting the chip from GDB

You may reset the chip using GDB if you want. You'll need to use `target
extended-remote' command like in this session:

```
(gdb) target extended-remote localhost:4242
Remote debugging using localhost:4242
0x080007a8 in _startup ()
(gdb) kill
Kill the program being debugged? (y or n) y
(gdb) run
Starting program: /home/whitequark/ST/apps/bally/firmware.elf
```

Remember that you can shorten the commands. `tar ext :4242' is good enough
for GDB.

## Setting up udev rules

For convenience, you may install udev rule files, located
in the `etc/udev/rules.d` directory. You will need to copy it to /etc/udev/rules.d,
and then either execute as root (or reboot your machine):

```
$ udevadm control --reload-rules
$ udevadm trigger
```

Udev will now create a /dev/stlinkv2_XX or /dev/stlinkv1_XX file, with the appropriate permissions.

## Running programs from SRAM

You can run your firmware directly from SRAM if you want to. Just link
it at 0x20000000 and do

```
(gdb) load firmware.elf
```

It will be loaded, and pc will be adjusted to point to start of the
code, if it is linked correctly (i.e. ELF has correct entry point).

## Writing to flash

The GDB stub ships with a correct memory map, including the flash area.
If you would link your executable to 0x08000000 and then do
(gdb) load firmware.elf
then it would be written to the memory.

## FAQ

Q: My breakpoints do not work at all or only work once.

A: Optimizations can cause severe instruction reordering. For example,
if you are doing something like `REG = 0x100;' in a loop, the code may
be split into two parts: loading 0x100 into some intermediate register
and moving that value to REG. When you set up a breakpoint, GDB will
hook to the first instruction, which may be called only once if there are
enough unused registers. In my experience, -O3 causes that frequently.

Q: At some point I use GDB command `next', and it hangs.

A: Sometimes when you will try to use GDB `next' command to skip a loop,
it will use a rather inefficient single-stepping way of doing that.
Set up a breakpoint manually in that case and do `continue'.

Q: Load command does not work in GDB.

A: Some people report XML/EXPAT is not enabled by default when compiling
GDB. Memory map parsing thus fail. Use --enable-expat.

## Currently known working combinations of programmer and target

STLink v1 (as found on the 32VL Discovery board)

Known working targets:

* STM32F100xx (Medium Density VL)
* STM32F103 (according to jpa- on ##stm32)

No information:

* everything else!

STLink v2 (as found on the 32L and F4 Discovery boards), known working targets:

* STM32F030F4P6 (custom board)
* STM32F0Discovery (STM32F0 Discovery board)
* STM32F100xx (Medium Density VL, as on the 32VL Discovery board)
* STM32L1xx (STM32L Discovery board)
* STM32F103VC, STM32F107RC, STM32L151RB, STM32F205RE and STM32F405RE on custom boards
  from [UweBonnes/wiki_fuer_alex](https://github.com/UweBonnes/wiki_fuer_alex/tree/master/layout)
* STM32F103VET6 (HY-STM32 board)
* STM32F105RCT6 (DecaWave EVB1000 board)
* STM32F303xx (STM32F3 Discovery board)
* STM32F407xx (STM32F4 Discovery board)
* STM32F429I-DISCO (STM32F4 Discovery board with LCD)
* STM32F439VIT6 (discovery board reseated CPU)
* STM32L052K8T6 (custom board)
* STM32L151CB (custom board)
* STM32L152RB (STM32L-Discovery board, custom board)
* STM32F051R8T6 (STM320518-EVAL board)

STLink v2-1 (as found on the Nucleo boards), known working targets:

* STM32F401xx (STM32 Nucleo-F401RE board) 
* STM32F030R8T6 (STM32 Nucleo-F030R8 board)
* STM32F072RBT6 (STM32 Nucleo-F072RB board)
* STM32F103RB (STM32 Nucleo-F103RB board)
* STM32F303RET6 (STM32 Nucleo-F303RE board)
* STM32F334R8 (STM32 Nucleo-F334R8 board)
* STM32F411RET6 (STM32 Nucleo-F411RE board)
* STM32F756NGHx (STMF7 evaluation board)
* STM32L053R8 (STM32 Nucleo-L053R8 board)
* STM32F769NI (STM32F7 discovery board)

Please report any and all known working combinations so I can update this!

## Known bugs

### Sometimes flashing only works after a mass erase

There is seen a problem sometimes where a flash loader run error occurs and is resolved after mass-erase
of the flash:

```
2015-12-09T22:01:57 INFO src/stlink-common.c: Successfully loaded flash loader in sram
2015-12-09T22:02:18 ERROR src/stlink-common.c: flash loader run error
2015-12-09T22:02:18 ERROR src/stlink-common.c: run_flash_loader(0x8000000) failed! == -1
```

Issue(s): [#356](https://github.com/texane/stlink/issues/356)

## Contributing and versioning

* The semantic versioning scheme is used. Read more at [semver.org](http://semver.org)
* When creating a pull request, please open first a issue for discussion of new features
* TODO: Enforcement of coding style (linux codestyle + checkpatch)

## License

The stlink library and tools are licensed under the [BSD license](LICENSE). With
some exceptions on external components.