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6500 Series

I am no longer active in this hobby for the foreseeable future. 
I will no longer maintain or update the website, but I will leave it accessible to the web for as long as possible (years).


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6500 Series Processor Board

Ta-da! The very first 6501 processor from The Digital Group--sort of. The 6501 chip in this photo was given to Dr. Robert Suding by Chuck Peddle, the designer of the chip. Dr. Suding gave the chip to me in 2004. This board, although built up especially for this chip, was a bare board I picked up from Marty Giest. Thanks Marty! The 6501 chip by MOS Technology had barely been introduced when Motorola threatened a lawsuit over the fact that this chip was a direct pin for pin replacement for the 6800. Since Chuck had previously worked for Motorola, who knows what might have have happened in court--MOS decided not to find out, and agreed to quit the 6501--Hello 6502!

Dr. Suding made this board able to accept a 6501, 6502, and 6800 by just a few jumper changes. The 6502 was modestly successful for The Digital Group, but didn't hold a candle to the success of the Z80, therefore, no software support. :(

2008-05-27a_127.jpg (1714048 bytes)
Fully (almost!) Restored 6501 Processor Board


This board is not a restoration, unlike most everything else on this site. Since I received the board bare, there was not much needed except to construct what I wanted. I had recently acquired the 6501 chip from Dr. Suding, so I felt this was the way to go. All the chips used are from other Digital Group stock I have, so everything but the IC sockets came from DG. That's pretty authentic, right? After construction was completed, the board was tested with a 6800 chip, and runs fine, but I have yet to actually power it up with the 6501 chip. The 1702 ROM shown in these photos lost it's mind and is plugged in for show. I have the ROM code listings, and know folks with the correct programmer, I'm just busy--I'll get it soon. I promise. Even after I have the ROM reprogrammed, will I dare power up that ultra, super, truly rare 6501 Chip? This is arguably the rarest processor chip in the world! Hmmm.

2008-05-27a_122.jpg (1801360 bytes)
6501 Processor Board, Solder Side

6500 Series Card Information

6502_CPU_Construction.PDF - Assembly instructions for the 6500 Series and 6800 card with schematics and board layout. Kind of a terrible copy--I have a better one now, one day I'll scan and upload it here. See my Document archive for more related files.

6500-10A_MCS6500hwMan_Jan76.pdf - MOS Technology 6500 Series Hardware Manual
6500-50A_MCS6500pgmManJan76.pdf - MOS Technology 6500 Series Software Manual

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6501 Processor Board, Layout


Photos During Rebuild:

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Bare 6501-2 Processor Board

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Cleaning solder flux from completed board

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Still in the bath--front side


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Copyright 2008 Bryan's Old Computers
Last modified:
October 16, 2009