Another 8-bit machine in the making

Paladin (858)

12-09-2019, 23:27

In this video the 8-Bit Guy talks about his project of building a new 8-bit machine. Although starting from Commodore roots, it's heading more towards the MSX architecture i.e. separate VRAM (including the addition of VPOKE to Basic), memory mapping and eventually maybe even a Yamaha sound-chip (currently still two PSG chips).

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Par alexito

Paladin (761)

12-09-2019, 23:52

I watched the video is really amazing that vira vdp can make 2 background layers/planes with scroll and sprites.
I wonder if that VDP board can be used in a MSX Computer.

Par keith56

Master (162)

13-09-2019, 01:12

If anyone's interested, I'll be covering this system in my 6502 assembly tutorials,

I did an early test of the 256 color mode here...
https://www.youtube.com/watch?v=iDDg5VYjWXY

Par erpirao

Paragon (1315)

13-09-2019, 06:59

65816 is not the cpu of snes?
They are 16bit, right?
in 8bits we already had the kiwi which is very interesting

Par PingPong

Enlighted (4140)

13-09-2019, 09:12

the v9990 did it before 2000. this was an amazing chip

Par hamlet

Scribe (4106)

13-09-2019, 11:58

I've become a bit tired of the self-constructed calculators. I don't want to question the engineering performance, but the technical limits seem arbitrary.
So I see no difference to program a game retrodesigned on a modern PC or on such a homebrew computer.
Nice to see and marvel at, but I don't want to delve deeper into this matter.
As you mentioned, with the Kiwi there is already a powerful model, to get lost in details now has no attraction for me.

Par erpirao

Paragon (1315)

13-09-2019, 12:05

"old" new 8 bits system: V6z80P
blog v6z80p
v6z80p demo

Par keith56

Master (162)

13-09-2019, 15:03

the 65816 is sort of 16 bit... and YES, it's used by the SNES (also the Apple II GS)

I believe it still has an 8 bit address bus, but it's registers are full 16 bit width - so call it 16 bit if you want!... it can run in 6502 mode - I've never switched it into 16 bit mode for my SNES tutorials yet - they're all pure 6502 code

I'm hoping to go more into the 65816 next year in my tutorials, but to be honest it's a pain, as you have to tell the assembler when the CPU switches mode between 6502 compatibility and full 65816 (and even certain registers), as the ASM compiles to different instructions

Par Manuel

Ascended (19469)

13-09-2019, 23:24

They say the AY-3-8910 can't go higher than about 2MHz... Strange, I thought it runs at the usual 3.58 MHz on MSX... or am I mistaken here?
Can the YM2149 perhaps be driven by higher clocks? Hmm, datasheet says 1-4MHz....

Par Grauw

Ascended (10772)

13-09-2019, 23:50

It’s clock divided /2. The YM2149 has a built-in /2 clock divider which can be activated with a pin.

Par Manuel

Ascended (19469)

13-09-2019, 23:57

What would be a good sound chip alternative for 8-bit guy's computer?