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hosted/README: Performed a fairly thorough rewrite of the BMDA readme…
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… to fix a lot of factual errors and issues
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@dragonmux
dragonmux committed Jan 11, 2024
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# PC-Hosted BMP
# Black Magic Debug App (BMDA)

Compile with:

```sh
meson setup build
meson compile -C build
```

## Description
PC-hosted BMP run on the PC and compiles as "blackmagic". When started,
it either presents a list of available probes or starts the BMP process
if either only one probe is attached to the PC or enough information is
given on the command line to select one of several probes.

When started without any other argument beside the probe selection, a
GDB server is started on port 2000 and up. Connect to the server as you would
connect to the BMP with the CDCACM GDB serial server. GDB functionality
is the same, monitor option may vary.

More arguments allow to
### Print information on the connected target

BMDA runs on your computer and compiles as `blackmagic`.
When started, it either presents a list of available probes or starts a GDB server on
localhost port 2000 if possible (if there's already something bound, it tries the next
4 port numbers up to 2004), and if there is either only one probe is attached to the
computer or enough information is given on the command line to select one of several probes.

You can connect to the server as you would connect to the BMP over USB serial, replacing
the device path with `:2000` as in `target extended-remote :2000`. BMDA's GDB functionality
is the same, but the monitor options are a little different and can be viewed with `monitor help`.

The following lists some of the supported additional commmand line options and what they do.
It is not exhaustive, and does not show how they can all be combined.

### Display the complete program usage help on the console

```sh
blackmagic -h
```

### Run "Test Mode" and display any connected targets

For SWD:

```sh
blackmagic -t
```
### Directly flash a binary file at lowest flash address

For JTAG:

```sh
blackmagic -tj
```
blackmagic <file.bin>

### Directly flash a binary file at lowest flash address

```sh
blackmagic <file>
```

or with the -S argument at some other address

```sh
blackmagic -S 0x08002000 <file>
```
blackmagic -S 0x08002000 <file.bin>
```

NB: BMDA will treat whatever file you provide here as the raw contents to write to Flash.
It does not understand ELF, Intel Hex, or SREC formats.

### Read flash to binary file

```sh
blackmagic -r <file>
```
blackmagic -r <file>.bin
```

### Verify flash against binary file

```sh
blackmagic -V <file>
```
blackmagic -V <file>.bin
```
### Show more options
```
blackmagic -h
```

### Show available monitor commands
```

```sh
blackmagic -M help
```
### Show available monitor commands on second target
```

### Show available monitor commands for the second target found

```sh
blackmagic -n 2 -M help
```
### Monitor commands with multiple arguments, e.g.Stm32F1:
```

### Monitor commands with multiple arguments - e.g. for STM32 option bytes

```sh
blackmagic -M "option help"
```
## Used shared libraries:
### libusb
### libftdi, for FTDI support

## Other used libraries:
### hidapi-libusb, for CMSIS-DAP support
## Dependencies for non-`HOSTED_BMP_ONLY=1` builds

## Compiling on windows
BMDA uses the following external libraries to function when built in full:

You can crosscompile blackmagic for windows with mingw or on windows
with cygwin. For support of other probes beside BMP, headers for libftdi1 and
libusb-1.0 are needed. For running, libftdi1.dll and libusb-1.0.dll are needed
and the executable must be able to find them. Mingw on cygwin does not provide
a libftdi package yet.

PC-hosted BMP for windows can also be built with [MSYS2](https://www.msys2.org/),
in windows. Make sure to use the `mingw64` shell from msys2, otherwise,
you may get compilation errors. You will need to install the libusb
and libftdi libraries, and have the correct mingw compiler.
You can use these commands to install dependencies, and build PC-hosted BMP
from a mingw64 shell, from within the `blackmagic` directory:
```
pacman -S mingw-w64-x86_64-libusb --needed
pacman -S mingw-w64-x86_64-libftdi --needed
pacman -S mingw-w64-x86_64-gcc --needed
meson setup build
cd build
meson compile
```
* libusb1
* libftdi1 (except on Windows)
* hidapi (hidapi-hidraw for Linux)

For support of other probes beside BMP, libusb access is needed. To prepare
libusb access to the ftdi/stlink/jlink/cmsis-dap devices, run zadig
https://zadig.akeo.ie/. Choose WinUSB(libusb-1.0).
## Compiling on windows

To build BMDA on Windows,
[please see the guide on the website](https://black-magic.org/knowledge/compiling-windows.html)

Running cygwin/blackmagic in a cygwin console, the program does not react
on ^C. In another console, run "ps ax" to find the WINPID of the process
and then "taskkill /F ?PID (WINPID)".
It is possible to build BMDA for Windows under Linux using Clang-cl or a MinGW compiler and combining
in the Windows SDK headers and link libraries aquired using `xwin`, but this is outside the scope of
this guide.

## Supported debuggers
REMOTE_BMP is a "normal" BMP usb connected

| Debugger | Speed | Remarks
| ------------ | ----- | ------
| REMOTE_BMP | +++ | Requires recent firmware for decent speed
Probes below only when compiled with HOSTED_BMP_ONLY=0
| ST-Link V3 | ++++ | Requires recent firmware, Only STM32 devices supported!
| ST-Link V2 | +++ | Requires recent firmware, No CDCACM uart! Cortex only!
| ST-Link V2/1 | +++ | Requires recent firmware, Cortex only!
| CMSIS-DAP | +++ | Speed varies with MCU implementing CMSIS-DAP
| FTDI MPSSE | ++ | Requires a device description
| J-Link | - | Limited support for hardware prior to v8

| Debugger | Speed | Remarks
| ------------- | ----- | ------
| BMP | +++ | Requires recent firmware for decent speed
| ST-Link v3* | ++++ | Requires recent firmware, Only STM32 devices supported!
| ST-Link v2* | +++ | Requires recent firmware, No CDCACM uart! Cortex only!
| ST-Link v2.1* | +++ | Requires recent firmware, Cortex only!
| CMSIS-DAP* | +++ | Speed varies with devuce implementing CMSIS-DAP
| FTDI MPSSE* | ++ | Requires a device description
| J-Link* | - | Limited support for hardware prior to v8

The probes in this table marked with a star only apply for a full build.

## Device matching

As other USB dongles already connected to the host PC may use FTDI chips,
cable descriptions must be provided to match with the dongle.
To match the dongle, at least USB VID/PID that must match.
If a description is given, the USB device must provide that string. If a
serial number string is given on the command line, that number must match
with serial number in the USB descriptor of the device.

## FTDI connection possibilities:
## FTDI connection possibilities

| Direct Connection |
| ----------------------|
Expand All @@ -123,8 +136,9 @@ with serial number in the USB descriptor of the device.
| MPSSE_DI <-- JTAG_TDO |
| MPSSE_CS <-> JTAG_TMS |

\+ JTAG and bitbanging SWD is possible<br>
\- No level translation, no buffering, no isolation<br>
\+ JTAG and bitbanging SWD is possible\
\- No level translation, no buffering, no isolation

Example: [Flossjtag](https://randomprojects.org/wiki/Floss-JTAG).

| Resistor SWD |
Expand All @@ -137,45 +151,44 @@ BMP would allow direct MPSSE_DO ->JTAG_TMS connections as BMP tristates DO
when reading. Resistor defeats contentions anyways. R is typical chosen
in the range of 470R

\+ MPSSE SWD possible<br>
\- No Jtag, no level translation, no buffering, no isolation<br>
\+ MPSSE SWD possible\
\- No Jtag, no level translation, no buffering, no isolation\

|Direct buffered Connection|
|--------------------------|
| MPSSE_SK -B-> JTAG_TCK |
| MPSSE_DO -B-> JTAG_TDI |
| MPSSE_DI <-B- JTAG_TDO |
| MPSSE_CS -B-> JTAG_TMS |
| Direct buffered Connection |
|----------------------------|
| MPSSE_SK -B-> JTAG_TCK |
| MPSSE_DO -B-> JTAG_TDI |
| MPSSE_DI <-B- JTAG_TDO |
| MPSSE_CS -B-> JTAG_TMS |

\+ Only Jtag, buffered, possible level translation and isolation<br>
\- No SWD<br>
Example: [Turtelizer]http://www.ethernut.de/en/hardware/turtelizer/index.html)
\+ Only Jtag, buffered, possible level translation and isolation\
\- No SWD

Example: [Turtelizer](http://www.ethernut.de/en/hardware/turtelizer/index.html)
[schematics](http://www.ethernut.de/pdf/turtelizer20c-schematic.pdf)

The 'r' command line arguments allows to specify an external SWD
resistor connection added to some existing cable. Jtag is not possible
together with the 'r' argument.

### Many variants possible
As the FTDI has more pins, these pins may be used to control

As FTDI devices have more pins, these pins may be used to control
enables of buffers and multiplexer selection in many variants.

### FTDI SWD speed

SWD read needs two USB round trip, one for the acknowledge and one
round-trip after the data phase, while JTAG only needs one round-trip.
For that, SWD read speed is about half the JTAG read speed.

### Reset, Target voltage readback etc

The additional pins may also control Reset functionality, provide
information if target voltage is applied. etc.

### Cable descriptions

Please help to verify the cable description and give feedback on the
cables already listed and propose other cable. A link to the schematics
is welcome.

## Feedback
### Issues and Pull request on https://github.com/blackmagic-debug/blackmagic/
### Discussions on Discord.
You can find the Discord link here: https://1bitsquared.com/pages/chat
### Blackmagic mailing list http://sourceforge.net/mail/?group_id=407419

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