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This accelerator comes with a 26,67MHz or 40MHz 68030 processor (incl. MMU) in gold/ceramic and 128MBytes physical memory. 1MByte of this memory is reserved for Kickstart re-mapping.

The ACA1233n comes with a number of improvements over the predecessor ACA1233. Although clocked at the same speed, performance has been improved in almost every aspect.

The ACA1233 boards have much faster memory performance than any other accelerator before - especially with cache and burst enabled. That's because the burst sequence is the fastest-possible sequence that the 68030 can perform: It's a sequence of four 32-bit transfers in four CPU cycles, which has not been shown before we first introduced the ACA1230 in 2010. The result is outstanding performance, even in comparison with other 68030-based accelerators at higher clock rates.

The ACA1233 is PCMCIA-friendly: It will not disable the PCMCIA slot, so you can continue to use a networking card in that slot.


  • Memory auto-configuration
  • Dynamic clocking for power-saving
  • card enable/disable in software
  • memory available to onboard CPU if accelerator is switched off
  • faster clockport for RapidRoad gives 55% speed increase
  • new software compatibility settings
  • improved A1200 compatibility

Memory of the ACA1233n is auto-configuring. This means that all memory is available from a power-up without installing any software on the computer. The old ACAtune tool, which was required for our previous accelerators, is not required any more.

If you do not require full speed, the card can be slowed down in order to save power. The CPU governor program will monitor CPU requirement and adapt to the demands of your application, resulting in the best power/performance ratio for your use case.

Some software does not like accelerated execution. For these cases, the ACA1233n can be switched off in two steps: The first step is to switch off the 68030 CPU and give control to the CPU of the host computer. On an A1200, you can still use 9MBytes of fast memory, which are also auto-configuring. The second step is to switch off additional memory as well, getting the computer into it's stock state. If used on an ACA500 or ACA500plus, memory can NOT be used by the 68ec000 processor.

The clockport of the ACA1233n can either take an RTC module, or the RapidRoad USB host controller. Operation of RapidRoad is 55% faster than with the internal clock port of the A1200 computer. This function is available in all modes of operation on an A1200 computer, and on the ACA500plus. It is not available if the ACA1233n is operated on an ACA500.

If software is not compatible with 32-bit memory, Z3 autoconfig or newer Kickstart version, the ACA1233n allows downgrading to Z2 autoconfig, older Kickstart versions and also lets you switch off the so-called "trapdoor memory area". The MapROM function is even available on an A1200 if the 68030 CPU is switched off! This will let you use different Kickstart ROM versions without opening the computer and exchanging ROM chips.

Last not least, the ACA1233n features a new A1200 motherboard interface. Some A1200 main boards have been delivered with the wrong timing components and require modification for reliable use with accelerators (A1200 capacitors E123C and E125C may need to be removed). With the new improved interface, the ACA1233n is less likely to require these board patches. Although this has been tested extensively, timing patches may still be required.


We apologize for the delay - the ACA1233n software package is still in beta state. The latest version can be downloaded here: Media:ACA1233nLib.lha. It includes all documentation in Guide format, uses an installer script which also sets the right MMUlib configuration, ACAMparom supports loading Kickstarts from files, and the ACASwitchCPU command lets you disable all memory, reducing the A1200 to a plain 68020/2M Chipram computer.

Older versions: Media:ACA1233nLib_Beta2.lha and Media:ACA1233n_ALPHAtools01.lha (please only use if you encounter problems with the latest version and want to verify/compare against older versions!).

register reference

If you want to do low-level programming for the ACA1233n, please consult the ACA1233n_registers article. Please note that hacking hardware registers is not the recommended way of controlling your accelerator. Register reference is only given for people who do not use classic Amiga OS (for example M68k Linux or BSD). If you use the classic Amiga OS, please only use the ACA1233n library.

library reference

Functions of classic OS library are described in the the ACA1233n.library article.

use with Z-IV Zorro board

We do not recommend the use of Zorro expansions at all, as most of them don't even come close to a real Zorro implementation. However, the Z-IV board is the only one that comes very close to this goal, and you may be able to get it working properly in a well-grounded tower case with a proper DC-DC converter-based power supply. Note that the standard P8/P9 based power supplies are mostly NOT DC-DC-converter based. Further, please note that the Z4 board has been equipped with 47µF/16 electrolytic SMD capacitors that need to be replaced (ideally with ceramic capacitors) for proper operation after all these years.

The Z-IV Zorro expansion was sold under different names, such as "Winner Z4" or "Elbox Z-IV". Please note that neither Vesalia, nor Elbox are the manufacturer of this board. It was originally designed and manufactured by ACT Elektronik GmbH from Recklinghausen, Germany. The jumper position to be used in conjunction with the ACA1233n is:

  • CFG M: open
  • CFG 0: close
  • CFG 1: open

Thanks to Benedykt Dziubałtowski for this jumper information.



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