Why C= never made a 65816 based machine?

[slaapliedje]

I often wonder what would have happened had Atari and Commodore merged instead of both dying off around the same time.  Atari lasted a little longer than Commodore, but not a whole lot.  Atari had basically announced the Falcon, then shortly after said "well screw computers, we're going back to Consoles, here's the Jaguar, behold it's awesomeness!" then afterward faded away into obscurity.

Commodore tried the same thing with the CD32, but much like the Jaguar, there weren't a whole lot of software titles that you couldn't already get for whatever 16/32 bit computer you had.  

Remember what Sega did with the Genesis?  They released a converter for Sega Master System games.  That's exactly what Atari and Commodore should have done for their 16/32 bit machines.  Just supply some 5.25" floppy drive that had some hardware in it for emulation.  Would have been a killer product and allowed established software categories to be utilized on newer systems.

Of course the problem with this is that it's too 'nice' to the consumers, and management figures most people wouldn't part with the cash to get the newer versions of conversions.  But honestly, would you stay with the crappy version of Double Dragon for the C64, when you could get the far better version for the Amiga?

slaapliedje

[mongo]

Remember what Sega did with the Genesis?  They released a converter for Sega Master System games.  That's exactly what Atari and Commodore should have done for their 16/32 bit machines.  Just supply some 5.25" floppy drive that had some hardware in it for emulation.  Would have been a killer product and allowed established software categories to be utilized on newer systems.

The "some hardware in it for emulation" would have had to consist of pretty much a complete C-64 and 1541.

Sega's Power Base Converter for the Genesis was just an adapter that allowed the different sized Master System cartridges to plug into a Genesis. There was no emulation involved because the Genesis contains the full hardware of the Master System.

[WolfToTheMoon]

One other area that C= sadly neglected was the mobile market. I would imagine that a cheap 65xx or 65xxx design would have sold very well(LCD was rumored to have had 15 000 orders on launch, before cancellation)  and that the 16 and 32 bit 65 versions would be great for cheap PDAs later.


I always believed it was a big mistake that C= never persued further 6502 development as they had great talent in MOS technologies - the future Athlon K7 designer worked on C65's CPU. Browsing the web, I have found indications that Tramiel pretty much killed any serious development shorty after aquiring MOS - some former engineers claim that a 32 bit version of the 6502 was being in the works at the time. This could have had major implications for C= as it was possible that it would have been chosen by, for instance, Apple for the Mac and further evolution of the II series...

[6502addict]

perhaps simply because the 65c816 has bug

I discovered with the W65C816SXB board that it was not working correctly in emulation mode

if you try this code in emulation mode

     LDA #$FF
     STA  $40
     STA  $41
     LDY  #$02
     LDA  ($40), Y

either you have an error if the machine only has 64k of memory
or if the read works you get a byte from $010001 and not from $000001

there is probably a work around by taking into account the E flag
while loading the latch (if in emulation the latch is kept a $00 it should work)

[psxphill]

I discovered with the W65C816SXB board that it was not working correctly in emulation mode

Interesting thread here too.

http://forum.6502.org/viewtopic.php?f=1&t=5803

It looks intentional


or the base is specified by sixteen bits and assumes the data bank as its bank, then, if an index plus the low-order sixteen bits of its base exceeds $FFFF, it will temporarily (just for the current instruction) increment the bank. The 65816 assumes that the array being accessed extends into the next bank.

[cgutjahr]

The 65816 was (briefly) considered for the C128 design, but a lot of people in engineering weren't exactly fans of the CPU design and software support (read: assemblers) was very immature in 1984.

Before the A2000 and A500 were greenlit, Commodore Engineering was proposing a range of different projects. One of them was a C128 follow up referred to as "BMW" and "C256", IIRC. Hayne was designing the specs, and he wanted to include a 65816, despite concerns from other engineers. That machine would not have been compatible with the 64, it would not have had CP/M and I imagine it would have been barely compatible with the 128. It got killed when new Amiga machines became the only priority.

[psxphill]

The 65816 was (briefly) considered for the C128 design

Bil Herd tells a different story. That he received a call from Bill Mensch trying to get him to use the 65816, which he immediately refused.

It wouldn't be commodore 64 compatible & it would be a chip they had to buy from an external company.