Possible MSX Kickstart Project ?

Page 4/7
1 | 2 | 3 | | 5 | 6 | 7

Par tvalenca

Paladin (728)

Portrait de tvalenca

22-02-2016, 20:21

erpirao wrote:

Wy not z180 @30mhz? ?
Z180 is full z80 compatible?

I don't think there any full compatible Z80 processor made by Zilog. Z80 developers used a lot the undocumented instructions and features. And even if they (Zilog) made a 100% Z80 compatible processor, We wouldn't be able to use them on MSX because of the internal add-ons that uses the same I/O ports used on MSX.

Par Dirty Harry

Resident (45)

Portrait de Dirty Harry

23-02-2016, 11:10

Overcloking a Z84C0020VEC is one possible option...I believe these can be Over-Clocked to 28MHz+ with no ill effects... then use a Z180 as a second CPU. This would allow all existing software to run and future software to take advantage of the Z180's extra features and speed.

Using an FPGA is trendy at the moments... but if your going to go down that route why not just buy an ALTERA DE board ? I think most MSX users want something that is basically a Faster and Better MSX2+ , but still using Retro (old School) components, Z80 CPU, V9958, SRAM, EPROM etc with perhaps Z180 second CPU, a second VDP, better sound PSG etc ?

Par Lord_Zett

Paladin (807)

Portrait de Lord_Zett

23-02-2016, 11:46

Learn from the victor hc95. It got a z80 and hc64b180 (z180ich)

Par tvalenca

Paladin (728)

Portrait de tvalenca

23-02-2016, 12:16

Dirty Harry wrote:

(...) I think most MSX users want something that is basically a Faster and Better MSX2+ , but still using Retro (old School) components, Z80 CPU, V9958, SRAM, EPROM etc with perhaps Z180 second CPU, a second VDP, better sound PSG etc ?

You thought wrong. Most MSX users doesn't care about a new processor, they already have the R800 since 1990 and not a single one of them cared to use its features (but its faster speed). Maybe a lot of little tests and proof of concepts, but I can't think of any R800 specific code. And if we didn't cared about R800, I don't think any of us want to learn to code in a another cpu, even if it's similar the z80. Sad but true.

Par maxis

Champion (512)

Portrait de maxis

23-02-2016, 15:00

tvalenca wrote:

I don't think there any full compatible Z80 processor made by Zilog. Z80 developers used a lot the undocumented instructions and features. And even if they (Zilog) made a 100% Z80 compatible processor, We wouldn't be able to use them on MSX because of the internal add-ons that uses the same I/O ports used on MSX.

Back in 1996 I've made a Z80S180 accelerator for MSX2. To my surprise all the Konami and other titles on cartridges worked on it, for exception of some demos. The built-in I/O map was placed into the lower addresses.

I wonder how many SW development companies were used non-documented instructions back in 80s?
IMHO - none.
Now we have wonderful simulators to prove or disprove whether the "New Z80 like candidate" is compatible or not.

I agree with you Tvalenca on a point where people actually don't care much about the CPU type (discrete or integrated) as long as it is Z80 compatible. They simply need a faster processor.

Par Lord_Zett

Paladin (807)

Portrait de Lord_Zett

23-02-2016, 15:44

make dual cpu system one z80 one other z80 like

Par maxis

Champion (512)

Portrait de maxis

23-02-2016, 16:00

Why not? It is possible even all in one FPGA.

Par RetroTechie

Paragon (1563)

Portrait de RetroTechie

23-02-2016, 17:00

Lord_Zett wrote:

make dual cpu system one z80 one other z80 like

Oh why not say, a 16-core Z80 system? (probably easiest in a big FPGA, but also doable with discrete Z80's). Because: such a beast would be very difficult to program effectively. So close-to-0 software would be written for it. Read: it would be much fun / interesting to design and build. Very nice as proof of concept. And very, very cool. But with near-0 practical use.

Besides: why go multi-Z80 route when an FPGA or other Z80-like cpu can do 100 MHz+ equivalent Z80 speed? Question Elsewhere, cpu's went multi-core because clock speeds couldn't (effectively) be boosted further. For our humble Z80 that's a non-issue.

Par Grauw

Ascended (8610)

Portrait de Grauw

23-02-2016, 18:20

Without FPGA, how else are you going to implement the MSX-Engine? MSX-Engine incorporated the Z80, PSG, PPI, etc., all of which have good FPGA implementations. Implementing this in FPGA is IMO totally in the MSX spirit, will save money and keep the board compact. Note that the MSX-Engine was created for the same reasons.

p.s. I love the R800 Smile.

Par tvalenca

Paladin (728)

Portrait de tvalenca

23-02-2016, 18:52

Grauw wrote:

p.s. I love the R800 Smile.

Have you ever used R800 specific instructions for anything serious?

Page 4/7
1 | 2 | 3 | | 5 | 6 | 7