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Accelerator board for the A500 and A2000. This board plugs into the CPU socket.
Processor: 68000@14Mhz/7Mhz (16Mhz component)
FPU: Optional 68881 (oscillator mmust also be obtained)
MMU: None
Ram: None (see below for special case with A1000 version)
A1000 includes a kickstart ROM socket for placing the ROMs on the accelerator. This allows the A1000 to boot without requiring a kickstart disk, therefore freeing up 256K of memory, normally reserved for the Kickstart to be used as Fast RAM using the provided AddMem utility.
The card can eb configured as either 14Mhz or 7Mhz using the software provided (PA), dropping to 7Mhz is to help with any backwards compatibility problems. Workbench 1.3 maths libraries are supplied to take advantage of the FPU if one is fitted.
Jumpers:
J1: Fast ROM
When the two jumper pins are shorted, the accelerator runs in "Fast ROM" mode where the Kickstart ROM is accessed with a reduced number of wait-states when the processor is running at 14Mhz. Some A500's and A2000's with Kickstart 1.3 are not able to handle this feature, and the jumper should be disabled.
J2: Forced 14 Jumper
Normally the PA program is used to switch the clock speed to 14MHz. This can be done using a project icon, or added to the startup-sequence. However, some self-booting games do not execute a startup sequence, and some users wish to run at 14mhz at all times. The jumper has 2 potitions, but pin 1 is not marked. Looking at the jumper with the (Jumper) 2 identifier upright, the right and middle pins jumpered will allow the processor to be switched between 7 and 14mhz using the software. The middle and left pins jumpered will force the processor to run at 14Mhz at all times.
Thanks to Ron Mascaro