Sergey also has schematics for an 8-bit Trident vídeo card, and 8-bit COM+Floppy controller card and an 8-bit 8088 XT/AT compatible SBC. XT-IDE/XT-CF is also an open design. So you can "easily" make an entire Turbo XT computer (with some AT/PS2 features added, like an RTC, more IRQs and PS/2 mice) with VGA, OPL2, floppy, COM ports and a HDD or CF card with self-made boards, A 486 is a much more complicated beast, with SMD chipsets with high pin count and a bunch of non off-the-shelf CIs. You'd also have to code a BIOS for it.

alexanrs wrote:

Sergey also has schematics for an 8-bit Trident vídeo card, and 8-bit COM+Floppy controller card and an 8-bit 8088 XT/AT compatible SBC. XT-IDE/XT-CF is also an open design. So you can "easily" make an entire Turbo XT computer (with some AT/PS2 features added, like an RTC, more IRQs and PS/2 mice) with VGA, OPL2, floppy, COM ports and a HDD or CF card with self-made boards, A 486 is a much more complicated beast, with SMD chipsets with high pin count and a bunch of non off-the-shelf CIs. You'd also have to code a BIOS for it.

Well I was only going to make the addin cards. And USA a off the shelf mobo and ram.

Well... I would not recommend using the 8-bit VGA card on a 486. The Trident chip he uses can also be used in 16-bit boards, so you could design an extended (16-bit) version of that. Also a 16-bit ISA IDE controller should not be hard to make. Would not be optimal (as far as 486 performance goes), but it is doable.

alexanrs wrote:

Well... I would not recommend using the 8-bit VGA card on a 486. The Trident chip he uses can also be used in 16-bit boards, so you could design an extended (16-bit) version of that. Also a 16-bit ISA IDE controller should not be hard to make. Would not be optimal (as far as 486 performance goes), but it is doable.

It's more for the fun of it. Maybe one day I'll do everything.