View Single Post
Old 24 February 2009, 00:51   #41
alexh
Thalion Webshrine
alexh's Avatar
 
Join Date: Jan 2004
Location: Oxford
Posts: 11,942
Quote:
Originally Posted by BoingBall View Post
I also helped porting FPGA64 (C64)
It shouldn't have taken long, it was a nice well presented open source project (Unlike Amstrad which is written entirely in AHDL) and the MiniMig I/O wrappers are reasonably well written and documented. Getting stuff on the screen and I/O control should have only taken a few hours (most of that reading + DCM configuring).

Loading the ROMs from SD card through the PIC to SRAM is the only hard bit. MiniMig uses a special "built in" bootloader ROM written in 68000 to move the Kickstart from the SD card using the floppy disk interface to the PIC over to SRAM before rebooting.

Quote:
Originally Posted by BoingBall View Post
We have a well working VIC20 core too. Additional some other little things like MiniPong etc.
Porting cores is very very easy once you've learned the interface wrappers (VGA, Keyboard, Sound, Joysticks).

When I first got my MiniMig board several years ago I had a go at porting C64, Amstrad, Spectrum, MSX2, Vic20 and more recently Atari ST.

The bootloader was the hard bit. It required re-writing some/all of the PIC to come up with a new way to program the FPGA and SRAM on power up. I got bored by this point and put it down.... never to pick it up again

I'd be curious to know if anyone wrote a new PIC/bootloader?

Last edited by alexh; 24 February 2009 at 01:01.
alexh is offline  
AdSense AdSense  
 
Page generated in 0.05216 seconds with 9 queries