I'm keen on getting some help with the firmware. Is anyone capable/willing to take on the role of 'main firmware developer'? So I can focus on purely the hardware side.
It can be written in any language, but since code size needs to be small, and the existing firmware is written in it, I propose C. Debugging will be via gdb and a jtag connection to the eclaireXL.
The firmware currently provides the following features:
i) USB HID joystick and keyboard decoding
ii) SD card reading, fat decoding
iii) SIO drive emulation
iv) Cartridge emu setup
v) OS/BASIC rom loading
vi) Video settings
I'm in the process of changing the core to be more a 'modern system' with the 6502 and antic as additional bus masters. Previously the 'ZPU' was bolted on top of the Atari as an afterthought.
The plan is to use the VexRiscV CPU (can compile with GCC, debug via GDB) and a crossbar wishbone interconnect. All the atari custom chips, USB hardware, SD card, will be mapped into a large linear address space. Then the 6502 and antic will access this via an address translation layer. With possibly a 2nd PIA to allow the 6502 to access some of the additional hardware and settings (e.g. turbo!).
I'm busily working on the hardware changes for this, which will take some time to build. After which I'll need to port or rewrite the firmware for the new setup. I think it needs a significant rewrite to be 'good' but I don't think I have the time/motivation for that. Is anyone up for the challenge?
Edited by foft, Sun Sep 10, 2017 2:56 PM.