eightbitswide
Member
New Thread started from a project proposal from the Commodore 64 on an Teensy 3.6 thread.
After seeing the Commodore 64 emulator running on the Teensy 3.6, I thought it may also be interesting to port the VIC emulation code to see if a project which replaces the VIC chip in the C64 with a Teensy with VGA output would be possible.
Reading through the schematic this afternoon, it looks like address and data lines could be grabbed from the C64's expansion port. The actual VIC chip could remain in the circuit, resolving the timing issues, etc.
Could your VIC-II code accept data from the data and address lines and act as an video output device?
The R/W. BA. Dot Clock, and IRQ lines appear to be easily accessible as well. Also will your code run on the slower Teensy 3.5?
Referenced from here: https://www.c64-wiki.com/wiki/Expansion_Port
C64 schematic: http://www.zimmers.net/anonftp/pub/cbm/schematics/computers/c64/250469-rev.A-right.gif
Sadly, my experience with Teensy is beginner level, since most of my previous work has been with Propeller, and PIC. I'm not afraid to dig into this as I suspect it would be a great project.
After seeing the Commodore 64 emulator running on the Teensy 3.6, I thought it may also be interesting to port the VIC emulation code to see if a project which replaces the VIC chip in the C64 with a Teensy with VGA output would be possible.
Frank B
Hm, might be possible.. But it would -still- be an emulation. I wonder, if a FPGA wouldn't be better.
The crystal input might be a bit problematic - on the other hand, it can be ignored, maybe ? The would mean, the c64-clock would be drivenby the teensy. We should take a look at the shematic - I'm not sure.
Reading through the schematic this afternoon, it looks like address and data lines could be grabbed from the C64's expansion port. The actual VIC chip could remain in the circuit, resolving the timing issues, etc.
Could your VIC-II code accept data from the data and address lines and act as an video output device?
The R/W. BA. Dot Clock, and IRQ lines appear to be easily accessible as well. Also will your code run on the slower Teensy 3.5?
Referenced from here: https://www.c64-wiki.com/wiki/Expansion_Port
C64 schematic: http://www.zimmers.net/anonftp/pub/cbm/schematics/computers/c64/250469-rev.A-right.gif
Sadly, my experience with Teensy is beginner level, since most of my previous work has been with Propeller, and PIC. I'm not afraid to dig into this as I suspect it would be a great project.