[Coco] 6 Chip 6809 Computer

[Kip Koon]

Hi Joe,
The PCB will be 2.7" x 3.09" not including the hangover of the 9-pin DB9 connector for the serial port.

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 Joe Grubbs
Sent: Thursday, February 26, 2015 6:06 PM
To: CoCoList for Color Computer Enthusiasts
Subject: Re: [Coco] 6 Chip 6809 Computer

This is great! Any idea how big the pcb will be, length x width

--- Original Message ---

From: computerdoc at sc.rr.com
Sent: February 26, 2015 6:02 PM
To: "Coco Email List" <coco at maltedmedia.com>
Subject: [Coco] 6 Chip 6809 Computer

Hi Guys,
I will not find out what the price is for the PCBs for 24 hours, so in the meantime I'll answer a few questions.  I love to put microprocessor controlled kits together myself, so I will be glad to provide this project in three forms - a bare PCB only for the experienced, a kit with some or all the parts for those that don't have the parts and don't want to search for them on the internet - just let me know how much of the parts list you would like, and finally a fully assembled PCB for those that want to get down to business right away.
NO CoCo compatible cpu chips will work like the MC68B09EP nor the HD63B09EP/HD63C09EP chips in this design!!!  It has to be an MC68B09P or the HD63B09P/HD63C09P cpu chips with at least a 2MHZ speed rating since a 7.3728MHZ crystal is used.  The "E" versions of these cpu chips requires an input frequency generated by some other part.  The footprints are different!
There is no baud rate generator in this design since the cpu divides the 7.3728MHZ frequency from the crystal by 4 to get the 1.8432MHZ required by the MC68B50P ACIA chip.
If you know your Motorola and Hitachi part numbers, then you know ceramic and cerdip versions of these chips will also work.
utsource.com and hkinventory.com are good sources for hard-to-get Motorola and Hitachi chips.  Shipping is approximately 3 weeks.
The PCB also uses a 32KB Static Ram chip that is compatible with several manufacturers' 32KB static ram chips.  The parts list shows an AS7C256 for example.  I pulled them from 486 motherboards.  They were used as the CPU's cache memory.
A standard 27C128 eprom chip is used to hold the BASIC interpreter.  the size of the binary rom image is approximately 9KB in size.
A 9-pin RS-232 serial I/O port is used for the console just like the original microcomputers of yesteryear used to require for communications with the human user.
Because this has no color nor B/W graphics, sound, joysticks, etc., all associated commands in Extended Color Basic have been removed, therefore Grant calls this Basic - 6809 Extended Basic.  This is a text only version of the CoCo's Extended Color Basic.  For full details, see http://searle.hostei.com/grant/6809/Simple6809.html.
The parts list is at
https://www.dropbox.com/s/lyvphltr2fc2xzt/Grant%27s%206-Chip%206809%20Computer%20-%20Exactly%20Like%20The%20Original%20Design%20tighter%20layout%20Partslist.txt?dl=0
in my dropbox.
This little 6 Chip 6809(6309) Computer is a great first project for beginning digital hardware builders learn from.  A complete B/W schematic will be provided with each kit and assembled PCB.
I originally designed an interface bus called the Kipper Bus as I initially had the idea to create a computer with 4" x 4" PCBs which I will gladly share the pinout to which is on an upgraded version of the this PCB.  The details is on my wiki page at the link in the signature.
If you have any further questions that are not answered on my wiki page (please read) or in my emails, just ask.
Thank you to all who have expressed an interest in this project.


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




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