[Coco] Kip's Single Board Computer

[Kip Koon]

Hi Jim,
Thanks for looking at my Kipper SBC.  I am also at a standstill as I so far have not figured out what is keeping the CPU from running.  As to the Crystal frequency compared to the 63C09P / 68B09P cpu chips, they both divide the Crystal frequency by 4 to arrive at the E Clock frequency of 7.3728MHZ / 4 = 1.8432MHZ.  This E clock 1.8432MHZ frequency output is used by the RXCLK and TXCLK inputs of the 68B50P ACIA.  If the crystal frequency was reduced, that would throw off the E clock frequency by the same amount/4 and though the CPU still may operate, the 68B50P would not have a standard RS-232 baud rate as the frequency of the RXCLK and TXCLK inputs would also be off from the expected 1.8432MHZ frequency.  Again thank you for helping me with my project.  I appreciate it very much.  Take care my friend.

Kip Koon
computerdoc at sc.rr.com
http://www.cocopedia.com/wiki/index.php/Kip_Koon


> -----Original Message-----
> From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of RETRO Innovations
> Sent: Monday, September 07, 2015 2:19 AM
> To: CoCoList for Color Computer Enthusiasts
> Subject: [Coco] Kip's Single Board Computer
> 
> Kip, working on debugging your 8 IC SBC, and I have a question:
> 
>   * The CPU on this board is a 62C09P, which it appears will run up to
>     3MHz, but you've installed a 7.37MH Crystal on the board. Was that
>     by design?  Am I missing something (like the 6309/6809 divides the
>     clock by some value?)
> 
> Otherwise, I think this SBC is not going to work unless we put a slower crystal in the design.
> 
> Jim
> 
> --
> RETRO Innovations, Contemporary Gear for Classic Systems www.go4retro.com store.go4retro.com
> 
> 
> --
> Coco mailing list
> Coco at maltedmedia.com
> https://pairlist5.pair.net/mailman/listinfo/coco