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Old 03 July 2014, 22:37   #175
FPGAmiga rulez!
FrenchShark's Avatar
Join Date: Dec 2007
Location: South of France
Age: 45
Posts: 155
Originally Posted by pandy71 View Post
AFAIR on A3000 CPU have 32 bit access to CHIP where chipset use 16 bit bus - bus conversion is performed by bunch of TTL's (mostly 74646) - later this was converted to LSI (Budgie on A1200 and Bridgette on A4000 - ).
So in theory AGA can be connected to 16 bit CPU bus but seem that even greedy Commodore abandoned such idea (IMHO it was never even prototyped). I found note about potential possibility to have MC68000 and AGA - see ",as well as 68000 based Amigas with AA chip set."

But knowledge that E clock is automatically recognized by Kickstart sounds nice - i need to check and double it - maybe 1MHz 8520 will be sufficient to work with 40% faster clock (especially after rising slightly 5V).
Interresting stuff about brigette.
In the case of an accelerator + AGA in an FPGA, the whole chip RAM bus and the CPU/Chip bridge is anyway integrated into the FPGA.
Moreover, it is easier to stay with 16-bit Chip RAM bus and to increase the bus speed than to use a 32-bit bus.

As for the faster 8520 hack, if it does not work you will end up with a Guru right away

I have one question about Kickstart 3.1 : does the A500/A2000 3.1 ROM contain AGA routines in the graphics library ?

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