English Amiga Board - View Single Post - Should the A1200 have used a 28Mhz 68000 processor instead?

Gorf · 10 August 2018, 18:32

Here is a nice an very detailed Blog about what it takes to speed up an Atari ST from 8MHz to 16MHz (and beyond) - not just the CPU but also access to the "ST RAM" (= our ChipRAM).

Very interesting as he tries many ways and documents not only success but also failure. It is not that easy ;-)

The date is being clocked into the shifter at double speed, so the display simply runs out of data each scan line. Apart from that, the GLUE and MMU control the video syncs so they become unsuable also. The only way it could work is to re-build the video syncs, and build a new shifter than can take increased data input speeds, but still output at the correct speeds.

Same would be true of course for the Amiga Custom Chips ...

but I guess Commodore could have done that, if they would have realized early enough that the Amiga is a "computer platform" and not just a one-hit wonder...

I think a real (switchable) 14MHz mode could/should be done by the time of ECS.

10 August 2018, 18:32	#98
Gorf Registered User Join Date: May 2017 Location: Munich/Bavaria Posts: 2,294	Here is a nice an very detailed Blog about what it takes to speed up an Atari ST from 8MHz to 16MHz (and beyond) - not just the CPU but also access to the "ST RAM" (= our ChipRAM). Very interesting as he tries many ways and documents not only success but also failure. It is not that easy ;-) The date is being clocked into the shifter at double speed, so the display simply runs out of data each scan line. Apart from that, the GLUE and MMU control the video syncs so they become unsuable also. The only way it could work is to re-build the video syncs, and build a new shifter than can take increased data input speeds, but still output at the correct speeds. Same would be true of course for the Amiga Custom Chips ... but I guess Commodore could have done that, if they would have realized early enough that the Amiga is a "computer platform" and not just a one-hit wonder... I think a real (switchable) 14MHz mode could/should be done by the time of ECS.