Quick start building notes for Linux, tested on a fresh install of Debian Bookworm, but should be very similar for any Debian derived distro. For other environments, see the pico getting started guide.
This is the bare minimum to get to the point where you can build a binary to copy to the Pico.
apt-get install git cmake gcc-arm-none-eabi libnewlib-arm-none-eabi build-essential libstdc++-arm-none-eabi-newlib
git clone https://github.com/raspberrypi/pico-sdk.git
cd pico-sdk
git submodule update --init
export PICO_SDK_PATH=`pwd`
cd ..
git clone https://github.com/CrashOverride85/zc95.git --recursive
cd zc95/source/zc95/
cmake .
make
cd ../zc624/
cmake .
make
This should result in the two pico binaries being built that can be copied to the pico.
- zc95/source/zc95/zc95.uf2 - for main board
- zc95/source/zc624/OutputZc.uf2 - for output board
For small fixes/changes/tweaks the above is fine, but requires manually copying to Pico via USB, and doesn't allow for debugging, so very quickly gets tedious for larger changes.
The pico-sdk integrates really well with Visual Studio Code & and an SWD debugger, allowing single keypress build & upload, along with setting breakpoints, stepping through code, etc., so that would be my recommendation for a development environment. For the SWD debugger, I'm using a J-Link as that's what I had, but a Picoprobe seems to be the Raspberry Pi recommend option, and well documented elsewhere.
Describing that setup is documented in the pico getting started guide, see Chapter 7 & Appendix A.
It's probably worth noting that the code is using both cores, so bare that in mind if unexpected things happen when debugging, setting break points, etc.