To Clock the FPU at a Higher Frequency than the CPU
4) If you wish to clock the FPU at a higher clock frequency than the MC68030, place a
black shorting block on the middle pin and the OSC pin of jumper
JP3
. You also
need to insert a crystal oscillator of the desired frequency into
U5
.
To Operate the Mega-Midget Racer without an FPU
5) To operate the
Mega-Midget Racer
without an FPU (MC68881 or MC68882), the
position of the black shorting block on the
JP3
jumper does not matter. We suggest
that you place it according to paragraph 3 above.
Setting the Sram Wait-State Jumpers:
6) If you are using 32-bit SRAM, you may need to change the jumpers to correspond to
the number of wait states appropriate for the clock frequency of the MC68030 and
the access time of the RAM. Contact CSA on the Technical Hot-Line (619) 566-
3923 for the proper jumper settings.
Setting the “ESYNC” Jumper:
7) Locate the
ESYNC
jumper,
W4
, located about two inches from the right side and
about an inch and a half from the bottom edge of the board. If you have installed your
68000 CPU in U7, then remove the black shorting block from
W4
. If
U7
does not
contain a 68000 CPU, then place a black shorting block on
W4
.
Verifying the “512K” Jumper Setting:
8) Locate the
512K
jumper,
W3
, located just above the
ESYNC
jumper. The
512K
jumper specifies the size of the ROM kernel to be supported by the SROM feature in
t h e C S A - M M R c o n f i g u r a t i o n s o ft w a r e . C u r r e n t l y, t h e A m i g a K i c k s ta r t R O M s ,
versions 1.2 and 1.3, are 256k bytes in size, although future versions may be
larger. The
512K
jumper is provided to support 512k byte versions of the ROM
kernel. For now, there should not be a black shorting block on
W3
.
Verifying the “68000” Jumper Setting:
9) Locate the
68000
jumper,
W2
, located just above and to the right of the
512K
jumper. When
W2
is shorted by a black shorting block or by a hardware switch, the
M e g a - M i d g e t R a c e r
b o o ts u p i n 6 8 0 0 0 m o d e . T h i s j u m p e r i s p r o v i d e d f o r t h e
installation of a hardware switch to select which processor boots up. As shipped,
there should not be a black shorting block on
W2
.
This completes preparation of the
Mega-Midget Racer
for installation. If
you have any questions, contact CSA on the Technical Hot-Line (619) 566-
3923 for assistance before proceeding.
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