Different GPIO Buttons

[Storm82]

Hi,
I have currently 4 buttons wired to the mt32-pi which are connected to different GPIO-Pins than in your source.

Could you tell me how I can change that to my GPIO-Pins?

I could even compile the source myself if I would know how to do it :)

Thanks

[dwhinham]

Hi,

The relevant lines are here for simple_buttons:

mt32-pi/src/control/simplebuttons.cpp

Lines 26 to 29 in 769a8f0

	constexpr u8 GPIOPinButton1 = 17;
	constexpr u8 GPIOPinButton2 = 27;
	constexpr u8 GPIOPinButton3 = 22;
	constexpr u8 GPIOPinButton4 = 23;

or here for simple_encoder:

mt32-pi/src/control/simpleencoder.cpp

Lines 26 to 31 in 769a8f0

	constexpr u8 GPIOPinButton1 = 17;
	constexpr u8 GPIOPinButton2 = 27;
	constexpr u8 GPIOPinEncoderButton = 4;
	constexpr u8 GPIOPinEncoderCLK = 22;
	constexpr u8 GPIOPinEncoderDAT = 23;

I don't have a compilation guide but the steps to build are listed in the GitHub Actions script, so you should be able to work it out from here:

mt32-pi/.github/workflows/ci.yml

Lines 33 to 49 in 769a8f0

	- name: Install toolchains if not retrieved from cache
	if: steps.cache-toolchains.outputs.cache-hit != 'true'
	run: |
	for triplet in arm-none-eabi aarch64-none-elf; do
	wget -q https://developer.arm.com/-/media/Files/downloads/gnu-a/${{ env.toolchain-version }}/binrel/gcc-arm-${{ env.toolchain-version }}-x86_64-${triplet}.tar.xz
	tar -xf gcc-arm-${{ env.toolchain-version }}-x86_64-${triplet}.tar.xz -C ~
	rm gcc-arm-${{ env.toolchain-version }}-x86_64-${triplet}.tar.xz
	done
	- name: Update PATH
	run: |
	for triplet in arm-none-eabi aarch64-none-elf; do
	echo "$HOME/gcc-arm-${{ env.toolchain-version }}-x86_64-${triplet}/bin" >> $GITHUB_PATH
	done
	- name: Build
	run: make -j BOARD=${{ matrix.board }}

I don't want to make individual GPIO pins a configurable option because I'm trying to keep the code and configuration as simple as possible, but feel free to create custom builds for your hardware.

Hope this helps!

[Storm82]

Thanks for your reply. I cannot figure out the compilation entirely :( I think it has to do with the toolchain

Could you compile a "special" version for me with GPIO-Pins 4, 10, 9 and 11? I would be very happy. Keep up the great work!

[dwhinham]

No problem, give this a try (I built Pi 3 and 4 because I wasn't sure which you had):

kernels-customgpio.zip

Yes; to build you basically need Linux (I use Ubuntu 20.04LTS) or WSL2, download and extract the correct ARM toolchain (currently 9.2.2019.12 for AArch64 but will change to GCC 10 very soon), extract to your home directory, add ~/gcc-arm-9.2-2019.12-x86_64-aarch64-none-elf/bin to your PATH and then make -j BOARD=pi3-64 or make -j BOARD=pi4-64.

I haven't spent any time documenting this properly because the project is still quite immature/in rapid development and I'm not really looking for code contributions from developers until things stabilise, but you are of course welcome to tinker 🙂