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small 68020

norwestrzh

Experienced Member
Joined
Jan 11, 2021
Messages
98
Location
mount vernon, wa
Here is a small footprint version of a 68020. It is quite similar to the small 68000 shown previously in this thread (Home Brew Computing). It has 2 MB SRAM, 64k EEPROM, 68681 DUART (2 serial ports, one is the console @ 38,400 k), and a compact flash interface via an 82C55 PPI. It is currently running at 25 MHz on a gold top 68020RC16E. I have tried a number of 25 and 33 MHz CPU's but 25 MHz is the fastest that I can get out of any of them. It runs CP/M 68k with sixteen 8 MB "disk drives". In experimenting with this design, I found that the bus timing for the 68020 is very different than the 68000/010. I didn't want to tangle with dynamic bus sizing, so it is locked to 8-bit. Performance is still very good.

Roger
 

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