Configure VUSB library from sketch

zont · December 5, 2021, 10:02pm

Hi!

I'm trying to wrap V-USB into a Library for Arduino IDE. I've got it working, but I can't configure it from the sketch. The code is quite old and using defines to configure most of the parameters, such as pin numbers, VID, PID, various USB descriptions, additional API/callback calls.

One idea is to have vusbconfig.h file in the sketch folder that is used when the library is compiled, but apparently the working directory is different from the sketch folder itself and compiler can't locate the file. The sketch directory is not listed during the building process (-I flag) either so I can't make it working. I tried both:

#include "vusbconfig.h"

and

#include <vusbconfig.h>

It works just fine when the full path is used from the library, but this will work only for a single sketch.

#include "/Users/zont/Documents/Arduino/vusb/vusbconfig.h"

Another idea is to have dummy header-only library that includes all code in the .h file. The problem with this approach is that I can't compile ASM code this way. I tried C-include and ASM-include:

asm(
#include "usbdrv/usbdrvasm.S"
);

asm(
".include \"usbdrv/usbdrvasm.S\""
);

but neither worked (compiler can locate the file, but compilation fails).

Please advise.

in0 · December 6, 2021, 4:40pm

That is correct. There is currently no way to do this out of the box with the official Arduino platforms.

The capability has been requested several times over the years, for example:

github.com/arduino/arduino-builder

Include global UserSettings.h file

opened 08:07AM - 24 Sep 15 UTC

closed 08:05AM - 19 Sep 19 UTC

NicoHood

type: enhancement

If we could have a global UserSettings.h file which is included at the top of th…e Arduino.h file we could: - Let the user add custom settings to an .ino file for libraries and the core itself - This way we can easily overwrite things like RX_BUFFER_SIZE as well. (without a boards.txt mod) - We could also add options to disable the USB-Core and other components if not needed - We could add an option to disable the SerialEvent function. You can keep it by default for compatibility, but set a few parameters to tweak the Arduino code and save some flash - We could use this for libraries, such as PinChangeInterrupt to effectively make use of direct port access with pre defined pins. This also works for other libraries. A known pin at runtime is way faster and also saves a lot of time. - Global debug options could be enabled this way. - Many more things I can imagine of and you as well. This requires every file to see the UserSettings.h file, it needs to be included in the Arduino.h file and it needs to be placed in the .ino folder, and if not it should be created as an empty file. Also make sure if you delete it, an empty dummy will be added again. Imported from: https://github.com/arduino/Arduino/pull/3757 Also fixes (and maybe more): https://github.com/arduino/Arduino/pull/3717 https://github.com/arduino/Arduino/issues/3635

It has not been very well received by Arduino, since they are concerned that it will result in library authors providing less user friendly interfaces.

I think there is some renewed interest in the subject, for example:

github.com/arduino/tooling-rfcs

Use of defines in reproducible builds

opened 08:10AM - 12 Jul 21 UTC

RobTillaart

Often builds have command line defines As these defines are part of the build… they must be includable in the profile. e.g. ``` profiles: nanorp: fqbn: arduino:mbed_nano:nanorp2040connect platforms: - platform: arduino:mbed_nano (2.1.0) libraries: - ArduinoIoTCloud (1.0.2) defines: - SIZE: 128 other: fqbn: ... platforms: - platform: .... libraries: - .... defines: - SIZE: 64 ``` If the user defines the define on the command line, it overrules the value in the profile ``` arduino-cli compile [sketch] --DSIZE=256--profile myProject ```

Did you try putting the code itself inline?

Juraj · December 7, 2021, 6:00am

you can put build.extra_flags in boards.local.txt

zont · December 8, 2021, 6:38am

Yes, it works just fine.

asm(R"(
usbCrc16:
    mov     XL, r24
    mov     XH, r25
    ldi     r24, 0
    ldi     r25, 0
...

The problem is that usbdrvasm.S file needs preprocessing first, because it uses includes to include other ASM files and bunch of defines to make code more readable. So I can't just copy/paste.

boards.local.txt is part of the platform specification. I don't immediately see how it can help with the library that I'm building. Can you elaborate please?

Juraj · December 8, 2021, 8:27am

from readme from my WiFiEspAT library:

To set different custom sizes of buffers for different boards, you can create a file boards.local.txt next to boards.txt file in hardware package. Set build.extra_flags for individual boards. For example for Mega you can add to boards.local.txt a line with -D options to define the macros.
mega.build.extra_flags=-DWIFIESPAT_TCP_RX_BUFFER_SIZE=128 -DWIFIESPAT_TCP_TX_BUFFER_SIZE=128

zont · December 12, 2021, 1:19am

Thanks for the tip!

This is what I ended up doing. Created platform.local.txt and added this line:

build.extra_flags=-I{build.source.path}

This is adding sketch folder to the include list. Then added this to VUSB library into the src/usbconfig.h file:

#if __has_include(<vusbconfig.h>)
#include <vusbconfig.h>
#endif

Now, whenever I add vusbconfig.h to the sketch it is automatically picked up by the library.

mrburnette · December 12, 2021, 1:52am

Very interesting.
I have done lots with V-USB in the past and RancidBacon had a working methodology but it never evolved beyond Arduino 1.0.x

Going to share on Github?

Ray

Please note that any references to hackster.io are no longer valid ... sadly, they went to the darkside and required registering.

https://forum.arduino.cc/t/v-usb-and-arduino/220318/3

mrburnette · December 12, 2021, 1:55am

V-USB and the tiny85:

zont · December 15, 2021, 6:06am

Sure. Here is my initial version. Example sketch Basic builds and runs fine on Arduino Nano. Currently working on few more examples, in particular Mouse, Joystick and Keyboard. Stay tuned.