X65

Modern 8-bit microcomputer

X65 is an effort to build an 8-bit microcomputer for the modern era. It uses best of breed components and strives to keep 8-bit feeling, while being usable for daily basis computing activities.

Dev Setup

This is only for building the RP2350 software. For writing 65816 CPU software, see rp6502-vscode.

Install the C/C++ toolchain for the Raspberry Pi Pico. For more information, read Getting started with the Raspberry Pi Pico.

sudo apt install cmake gcc-arm-none-eabi libnewlib-arm-none-eabi build-essential gdb-multiarch

sudo dnf install cmake gcc-arm-linux-gnu arm-none-eabi-newlib gcc-c++-arm-linux-gnu

All dependencies are submodules. The following will download the correct version of all SDKs. It will take an extremely long time to recurse the project, so do this instead:

git submodule update --init

The firmware builds x65_north (CPU bus, API and monitor) and x65_south (CGIA, terminal and audio transport). The SGU-1 sound core is maintained in its own repository.

To debug NORTH or SOUTH code, you need a Debug Probe or a Pi Pico as a Picoprobe.

The Pi Pico VSCode Extension will need this additional software:

sudo apt install build-essential gdb-multiarch pkg-config libftdi1-dev libhidapi-hidraw0

Create /etc/udev/rules.d/99-pico.rules with:

#Raspberry Pi Foundation
SUBSYSTEM=="usb", ATTRS{idVendor}=="2e8a", MODE="0666"

Debug terminal:

openocd -f interface/cmsis-dap.cfg -c "adapter speed 5000" -f target/rp2350.cfg -c "program build/src/x65_north.elf verify reset exit"

Console terminal:

picocom -b 115200 /dev/ttyACM0

WSL (Windows Subsystem for Linux) can forward the Picoprobe to Linux:

PS> winget install usbipd
PS> usbipd list

PS> usbipd wsl attach --busid 7-4

WSL needs udev started. Create /etc/wsl.conf with:

[boot]
command="service udev start"

VSCode Serial Monitor doesn't yet send breaks or let you slow down a paste. Minicom is still useful.

minicom -c on -b 115200 -o -D /dev/ttyACM0